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British Submarine Development and Policy 1918 - 1939.
Henry, D
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BRITISH SUBMARINE DEVELOPMENT AND POLICY
1918 - 1959
DAVID HENRY M. A.
PH. D WAR STUDIES
KING'S COLLEGE
UNIVERSITY OF LONDON
I1^ý '4 ý" -1-
ABSTRACT
Demobilization and retrenchment inevitably followed the close of the
First World War. They threatened not only to remove the additions to
British military strength provided by the war but also reduce the armed forces below their pre-war establishments.
British submarine policy, which had been tentative and uncertain before 1914, was not only subordinated to political and financial factors but suffered from a reluctance to develop a weapon which in enemy hands could be a grave threat to Britain's maritime interests. The Royal Navy's submarine strength was severely reduced in the immediate post-war years.
Moreover, the successes of the German wartime submarine campaigns influ- enced successive British Governments to press for the abolition of the
submarine, and the initial attitude of the Admiralty was that Britain
stood to gain more from the abolition of the submarine than from its
retention. Gradual recognition of the impracticality of securing inter-
national acceptance for this policy led to proposals to limit the offensive
power of the submarine by restrictions on size and performance.
The development of the Submarine Service was limited by domestic
economic policies and international arms agreements which placed constraints
on construction and improvement. The Submarine Service had to fight
initially for its survival and later for sufficient numbers of submarines
to enable it to make a significant contribution to British naval strategy.
The weakness of the British submarine force in September 1939 lay princip-
ally in the numbers of hulls available. This reflected a
belief in the continuing value of major surface units which were regarded
as the final arbiters of naval warfare. Naval planning was based on the
view that the submarine fulfilled no more than a subsidiary role in
British naval tactics; this led to the threat and potential of submarine -2-
warfare being dovmgraded and contributed to any Admiralty reluctance to resist Government pressure to curtail submarine development and constr- uction. Internationally as well as domestically, economic policy and a persistent belief in disarmament agreements kept the Submarine Service to a level which, only belatedly, was recognised as inadequate. -5-
C0NTENTS PAGE
4 Acknowledgement ...... 5 Abbreviations ...... 7 Introduction ...... Chapter 1 The Growth, Development and Acceptance of the Submarine. 1900-1918. 10 British .... Section A- Development. 2 Submarine 56 Chapter Patrol ...... 5 92 Chapter Cruiser Submarine ...... Chapter 4 Fleet Submarine 106 ...... 5 Seaplane Carrying Submarine 140 Chapter . .... Chapter 6 Minelayer Submarine 155 ...... 181 Conclusion...... Section B-P olicy. Chapter 7 Versailles and Washington Conferences. 1918-1922. 186 ...... Chapter 8 Domestic Submarine Policy and the 1927 Tripartite Naval Conference at Geneva. 1922-1927...... 235 Chapter 9 Anglo-French Discussions and 1930 London Naval Conference. 1928-1931. of .. 272 Chapter 10 Domestic Submarine and A/S Policy. 1931-1934. 315 Chapter 11 Anglo-German Naval Agreement and Preparations for the 1935 London Naval Conference. 1954-1955...... 548 Chapter 12 1935 London Naval Conference and Rearmament. 1955-1959...... 575 Conclusion. 415 ...... Appendices. A Office Holders 433 ...... B British Submarine Building Programmes. 1920-1939. 441
C British Navy Estimates and Expenditure. 1919-1939. 444 D British Submarine Classes, 1900-1939. 'Holland' to 'U' Class...... 445 E Prelimi nary Design Proposals for Certain Submarine models Classes. 482 and ...... F Various Proposals Submarine 491 on Types. .... G Tables of Fleet Strengths, Wartime Losses and Future Construction. 493 ...... H Resolut ions, Definitions, Agreements and Treaties. 514 1 British 1938-1939. Submarine Dispositions, .. 522 J Bibliography...... 527 -4-
ACKNOWLEDGE1dEN`P
I would like to express my gratitude to Professor Brian Ranft who, as supervisor, has tendered valuable advice and. displayed immense patience over the completion of this thesis. I am also grateful to the staffs of the Public Record Office; the Ministry of Defence Library (Naval); the
National maritime Museum; the Royal Naval College, Greenwich; Submarine
Museum, H. M. S. 'Dolphin', Gosport; Churchill College, Cambridge; the
Royal United Services Institute Library; and the Department of War Studies,
King's College, University of London. -5-
ABBREVIATIONS
Alk Anti-Aircraft
A. C. N.S. Assistant Chief of the Naval Staff
A/S Anti-Submarine
ASDIC Allied (or Anti-) Submarine Detection Investigation
Committee
B. E. D. British Empire Delegation
B. H. P. Brake Horse Power
C. I. D. Committee of Imperial Defence
D. C. N. S. Deputy Chief of the Naval Staff
D. E. E. Director of Electrical Engineering
D. G. D. Director of Gunnery Division
D. N. A. D. Director of Naval Air Division
D. N. C. Director of Naval Construction
D. N. E. Director of Naval Equipment
D. N. I. Director of Naval Intelligence
D. N. O. Director of Naval Ordnance
D. O. D. Director of Operations Division
D. of P. Director of Plans Division
D. R. C. Defence Requirements Committee (Sub-Committee of C. I. D. )
D. S. D. Director of Signals Division
D. S. R. Director of Scientific Research
T. D. D. of Director of Tactical Division (amalgamated in 1928 with
Torpedo Division)
D. T. M. Director of Torpedoes & Mining
D. T. S. Director of Tactical School
D. T. S. D. Director of Training and Staff Duties Division 6
E. -in-C. Engineer in Chief
E. W. P. C. Emergency War Programme Committee
F. O. Foreign Office
H. A. High-Angle
H. of M. Head of Mining
L. A. Low-Angle,
N. P. C. C. Naval. Programme Committee of the Cabinet
P. S. O. C. Principal Supply Officers Committee _ Q. F. Quick-Firing _ R. A. (S) Rear-Admiral (Submarines)
R. N. Royal Navy
S. H. P. Shaft Horse Power
S. of M. Superintendent of },Lining
S/ýS Submarine
T. B. Torpedo Boat _ T. T. Torpedo Tube
II Boat German submarine
W/T Wireless Telegraphy,, -7-
INTRODUCTION
The early decades of the twentieth century saw the introduction of two major weapons, the submarine and the aeroplane. Both systems posed problems for the conventional naval establishment, altering the traditional concept of naval warfare. For this reason, the new weapons were unwelcome; they were indeed opposed, tacitly and instinctively rather than deliber- ately, and only gradually came to be accepted. The aeroplane was the easier to accept since it could both be seen and countered - by another aeroplane, and it offered some obvious advantages to land forces. The submarine was covert and a more difficult problem; it was made more so by
Britain's reliance upon the sea for communication, supply, and defence.
Other types of new warship had proved possible to counter merely by building similar units but the submarine possessed the ability to submerge and once below the surface could not be easily dealt with. This ability, in the early years, to escape retribution by submergence proved extremely frustrating to naval officers used to only surface engagements and this was expressed in the description of the submarine as 'unEnglish'. The torpedo was the submarine's main offensive weapon, capable of being launched either from the surface or underwater. In the latter case this added to the problems of defence against the submarine; until it was located the surface forces had no warning of an impending attack. However, the ability älso to submerge created problems for the submarine. Existing technology restricted underwater propulsive power to motors driven by battery cells.
Endurance was limited as was the air supply, and speed was low. Thus, an early realisation was that if the submarine could be kept underwater the faster but more valuable capital ships could outrun their attacker and until the incentive of war brought the invention of a means both of -8-
detecting and attacking the submarine this was the only major option open to surface naval forces.
In this environment the Submarine Service had to struggle to survive; and then at the moment of acceptance found its existence threatened again.
The First World War which was to facilitate the creation of the means of countering the submarine proved also to be the moment to demonstrate its extensive power, not against b attlefleets but rather against the merchant fleets on which Britain in particular depended for supplies and survival in wartime. The intrinsic reservations which had existed from the begin- ning about the dangers that submarines embodied to British security were reinforced rather than-reduced by these experiences. At the time when resources for development and construction were flowing freely to the
British Submarine Service the success of the U-boats rekindled, fear and opposition to the very concept of the submarine. Thus in the very different circumstances of the post-war period the Submarine Service had to accept the fact that, to a greater extent than for many years, naval policy was to be governed by political and financial priorities rather than any perceived military necessity. Even though the euphoria of the Armistice period, with its talk of 'the war to end all wars' was short-lived, the disillusionments and the difficulties of the 1920's and 1930's meant short commons for the defence forces as a whole, and a series of expedients to maintain new, and not yet proved, weapons, like the submarine. Moreover the successes of the unrestricted U-boat campaigns influenced successive
British Governments to press for the international abolition of the submarine. Gradually, recognition of the impracticality of securing international acceptance for this policy led towards more functional proposals to limit the power of the submarine by means of size, numbers
and use. There were also many important technical problems of development -9-
to overcome but those problems arising from national and international
politics were infinitely greater and more complex. They amounted., in
fact to a discrimination against the Submarine Service that for many
years made it the poor relation, so far as the rest of the Navy was
concerned.
this The aim of thesis is to analyse the Admiralty's handling of
submarine policy and development and is therefore mainly based on Admiralty
documents in the Public Record Office, the submarine Archives at H. M. S.
'Dolphin' and the Admiralty Library. The result is an appraisal of the importance the of submarine to Britain from its earliest days, of the degree of competence and foresight attached to its development in the inter-war period, and, to the extent that it is possible to recreate the
subjective environment of the period, of. the quality of departmental and
thought that branch was given to the appreciation of the significance of the submarine.
The thesis will also trace the Admiralty's attitude towards the
British Government's disarmament and construction policies which were
beyond sometimes pushed the limits that the department had identified as
for reasonable and a period in the late twenties and early thirties were not contested; the effects of external and domestic factors, such as disarmament conferences and economic stringency, on the numbers and types of submarines envisaged and constructed; and finally how the British submarine force of 1939 came to be what it was.
To understand this it is first necessary to go back beyond 1918 to the early years of the twentieth century and trace the initial develop- ment-of the submarine in the-'Royal Navy. - - 10 -
CHAPTER 1
THE GROWTH, DEVELOPMENT AND ACCEPTM1CE
OF THE BRITISH SUBMARINE 1900 - 1918
British naval policy at the opening of the twentieth century was based on the strength of the battlefleet. Under the concept of the Two-
Power Standard the number of British capital ships was required to equal the number possessed by the next two strongest Navies. Therefore, the initially negative attitude of the Admiralty towards acquiring submarines was engendered by the potential threat to the capital ship as well as from a belief that this type of vessel would have a limited military use. The
First Lord, Viscount Goschen, said in 1900:
'The submarine boat, even if practical difficulties its be to attending use can overcome would seem ... be eventually a weapon for maritime Powers on the defensive, and it is natural that those nations which anticipate holding that position should endeavour to develop it that the ... It seems certain reply to this weapon must be looked for in other d}rections than in building submarine boats ourselves. '
Nevertheless, development of such craft by France and Germany soon caused a reconsideration of this opinion. The earlier failure to encourage development of the submarine in Britain meant that the Admiralty was forced to go abroad for submarine designs.
The first design chosen was based on the work of the American inventor A. P. Holland and a total of five of these submarines were built 2 by Vickers under licence. The first was commissioned in 1902 and the size and endurance were gradually increased through development of the
1. First Lord. of the Admiralty, Viscount Goschen, 6 Apr. 1900, Ser. 4, Vol. 81, Col.: 1402.
2. See Appendix: D(1). - 11 -
possessed 'A'3, 'B'4, and 'C'5 classes. These submarines limited endur- ance; the maximum patrol capability was four days in summer and three days in winter. Moreover, they were limited to coastal operations by a lack of sea-going qualities. The need to improve speed, endurance and sea-keeping qualities became evident, but naval designers were handicapped by the lack of a suitable diesel engine. The specifications for a larger type of submarine called for twin diesel engines of 600 B. H. P. each.
Eventually Vickers and Admiralty engineers were able to produce a satis- factory model. The first of the new class, 'D. 1'6, was commissioned early in 1910 and marked the beginning of the period when submarines could be regarded as offensive weapons of war.
Participation of submarines in Fleet :;exercises from 1904 had grad- ually developed an awareness of the use of submarines in a range of roles.
There appeared to be several possible functions, including reconnaissance, minelaying and blockade work. However, all these required an ability to remain unsupported on patrol for lengthy periods. Existing British submarine designs did not lend themselves to development of the larger
buoyancy reserve of which, allied to an increase in size, was seen as necessary for improved sea worthiness and navigation. Other improvements included, 'reduced risk of explosion and increased economy of working' (obtained by the substitution of diesel for petrol engines), 'and better manoeuvring power obtained by the introduction of twin screw propulsion. '?
3. See Appendix: D(2)
4. See Appendix: D(3)
5. See Appendix: D(4)
6. See Appendix: D(5)
7. Admiralty, 1919, ADM 1/8374/93, 'Submarine Engine Development in the. Royal Navy, 1900-181. See also: Admiralty, 25 Oct. 1910, ADM 158/246, National Maritime Museum N. M. M. ), 'New Submarine. Designs, 1910-111. - 12 -
The problem of providing a higher surface buoyancy was approached by designing the 'D' class as single-hull submarines with saddle type ballast tanks on either side of the pressure hull. This enabled 'D. l' to achieve improved surface and. submerged speeds over the 'C' class submarines.
Despite these advances, there were those, led by the new Inspecting 8 Captain of Submarines, Roger Keyes, who felt that not enough was being done to exploit the results of these developments: 'I don't think anyone
the immense lay in at the Admiralty ... realised possibility which have the knowledge to their submarine warfare ... people who not gauge limitations credit them with powers they certainly do not possess. '9
Admiral Sir Arthur Wilson10 having replaced Admiral Fisher11 as First Sea
Lord was instrumental in arranging Keyes's appointment. During the early years of submarine development in Britain, Wilson had been firmly opposed to these vessels, reportedly saying they were, 'underhand., unfair and damned unEnglish. ' However, the performance of the 'D' class showed the potential of the submarine to such an extent that even from a conservative
8. Keyes, Roger John Brownlovr, first Baron Keyes (1872-1945), Admiral of the Fleet; b. 4 Oct. 1872; Inspecting Captain and. Commodore in charge of the Submarine Service, Nov. 1910- Jan. 1915; Chief of Staff, Eastern Mediterranean Squadron, Feb. 1915; Grand Fleet Captain (H. M. S. 'Centurion'), June 1916-June 1917; Rear-Admiral, 1917; Director of'Plans, Oct. - Dec. 1917; Acting Vice-Admiral Dover Patrol, Jan. 1918-Feb. 1919; C. in C. Battle Cruiser Squadron, March 1919-Oct. 1921; Vice-Admiral, May 1921; Deputy Chief of the Naval Staff, 1 Nov. 1921-15 May 1925; C. in C. Mediterranean Fleet, 8 June 1925-7 June 1928; C. inC. Portsmouth, Apr. 1929-June 1951; Admiral of the Fleet, May 1950; off the Active List, May 1935; d. 26 Dec. 1945.
9. R. Keyes, The Naval Memoirs of Admiral of the Fleet, Sir Roger Reyes. (London, 1954 1,28. ,
10. Wilson, Sir Arthur Knyvet, third baronet (1842-1921), Admiral of the Fleet; b. 4 Mar. 1842; First Sea Lord., 1910-12; 1912; d. 25 May 1921. ret. _
ll. Fisher, John Arbuthnot, first Baron Fisher of Kilverstone (1841-1920), Admiral of the Fleet; b. 25 Jan. 1841; C. in C. Mediterranean Fleet, 1899-1902; Admiral, Nov. 1901; Second Sea Lord, 1902-3; C. in C. Portsmouth, Sept. 1903-Oct. 1904; First Sea Lord, 21 Oct. 1904-Jan. 1910 and Oct. 1914-17 May 1915; d. 10 July 1920. - 15 -
viewpoint the capabilities of such vessels could no longer be ignored.
Wilson was also concerned to prevent the Submarine Service and the rest of the Royal Navy from coming to regard each other as two separate forces.
Therefore, rather than appoint another materiel specialist such as a torpedo officer as Inspecting Officer, an officer with more general qualities of leadership and initiative as well as administrative ability* was required. Keyes was thought to fulfil these requirements and also able
view to take a broad of all submarine developments. In order to compensate for lack of specialist knowledge, Keyes appointed a small staff of technical experts to advise him. The initial view of the new head of the
Submarine Service confirmed Wilson's fear that this group of highly mötiveted officers and men were, after some years of discouragement from senior levels, tending to retreat into a 'separate-Service' attitude.
However, Keyes saw the major problem as the development of the submarine itself. A preoccupation with the local defence role, allied to restric- tions placed on development, had produced what was effectively a coastal submarine force, with the exception of 'D. l'; a further eight 'D' class were however now being built. This coincided with the knowledge that the
German Navy had a larger number of overseas submarines in service and building. The Admiralty had started design work on a -larger patrol
submarine but the planned orders were for only a total of eight of the 12 new 'E' class. This situation was caused partly because the Admiralty,
the Director through of Naval Construction, had only just assumed design
with responsibility, beginning the 'D' class. Further progress towards prothicing new designs and increasing construction were handicapped by the monopoly agreement held by Vickers.
12. See Appendix: D(6). - 14 -
During 'the early years of British submarine development there had been
advantages in allowing one shipbuilder to maintain a monopolistic position.
However, by 1910-11, the importance of safeguarding military developments was taking second place to the need to make up the ground lost to the
Germans and the French. Not only was the design of the proposed ?E' class being held up but Vickers, despite belated extensions to their shipyards,
were proving unable to keep to completion dates for existing contracts.
The Admiralty considered that the logical solution was to increase the
number of shipbuilders who could tender for submarine contracts. This was naturally opposed by Vickers and under the terms of their agreement
the Admiralty was barred from ordering Admiralty designs from other ship- builders if the designs included Holland patents. However, termination
of the Agreement, without mutual consent, called for a notice of two years
to be given. This was a strong incentive for the Admiralty to reverse its
it new policy and might have succeeded but for the stubborn opposition of
Inspecting. the new Captain of Submarines. The Agreement was officially
terminated on 31 March 1911 but so strong was the pressure from Vickers
for the a reversal of decision that Keyes felt it necessary to restate, in
July, the major reasons for ending the monopoly, concluding that,
'it is submitted that the decision to terminate the Agreement should be adhered to, for it has outlived its uses, and is in fact a hindrance to development if, as has been shred, it debars from us ordering ... from other Firms. '
This jaundiced view of the Vickers manoeuvres was still evident in Keyes's memoirs: 'Vickers, who were naturally loath to lose such a valuable monopoly, used every argument to get the notice withdrawn and I was very much afraid they would succeed. '14 Vickers, however, constructed their
13. Keyes to Admiralty, 20 July 1911, Keyes MW 421, C. N. 02408/11.
14. Keyes, op. cit, 28. - 15 - case inefficiently and the approaches they used were the wrong ones to win back Admiralty favour.
'The arguments used by Vickers might have been that they knew more about designing and building than learn submarines anyone else could quickly ... and that they could and would rapidly expand their capacity. These arguments might have found a good deal of favour in the Admiralty, especially when their in hand Vickers actually put expansion ... Even so it is not difficult to see now that Keyes was in the right at least in being anxious. '15
Certainly, Keyes was later to claim that it had been clear to himself and others that Germany, in particular, had gained a lead over Britain in the development of submarines by concentrating on the overseas submarine. In addition, Keyes favoured the use of such submarines in both the reconnais- sance and blockade roles: 'Submarines of the "El' class are considered to be very suitable for blockade duties off the Elbe if it is decided to use submarines on this service. '16 The hoped for result was acceptance of the submarine as an effective unit of the Fleet and in the Commodore (S)'s view the overseas submarine, 'should be capable of accompanying a modern fleet to sea, and should possess the highest possible speed for strategic 17 requirements. '
British or Continental Designs
Initially, however, the need remained to improve the poor construction rate of all types of submarines and an obvious solution was to expand the number of firms building them. However, problems arose because this meant, in effect, moving beyond the 'E' class design, which was partly of Vickers origin:
15. J. D. Scott, Vickers: a History (London, 1962), 67.
16. Keyes to Admiralty, 20 July 1911, Keyes MSS. (See Note 13).
17. Keyes to Admiralty, 18 Aug. 1913, Keyes LLSS 4/'11, 'Minute on First Lords Memorandum on Submarines. ' - 16 -
'Vie were getting more and more behind, and if other firms were to be brought into the field of submarine production, it was necessary to go abroad for designs as soon as possible, since, at the earliest our existing designs could not be given to them before April 1913. i19
meanwhile, Sir Philip Watts (D. N. C. ) had produced three designs in line with the requirement of the previous year for submarines capable of carrying broadside torpedo tubes. The designs were unofficially designated as 'French', 'Italian', and 'Improved E'. The latter design was simply an enlarged version of the existing 'E' class while the others were based on
Laubeuf and Laurenti designs respectively. Due to the apparent belief that the 'E' design did not lend itself to further development, opinion tended to favour the 'French' and. 'Italian' designs. The design philos- ophy appeared to be to extend the principle of high buoyancy in a more ambitious manner than in the saddle tank designs. It was believed that the higher the percentage of reserve buoyancy the less tendency there would be for the submarine to plunge or dive when running on the surface.
Because of this the continental designs were aimed at higher surface speeds than the fifteen knots of the 'E' class. The argument about which design to follow was made effectively theoretical by the two year cancellation period which prevented the 'use of any Vickers based designs by other ship- builders until March 1913. However, the D. N. C. was not prepared to recommend the construction of the continental designs because they incor- porated new and untried principles. The result was an increase in the proposed 'E' class building programme of eight submarines but Vickers had
still not completed the extensions to their building facilities and were
still unable to meet completion dates for existing orders. Therefore the
increased order for 'E' class submarines did little in the short term to
solve the shortage of overseas submarines.
18. Keyes, op. cit., 28. - 17 -
This led to the resurrection of the interest in continental designs as a means of bridging the gap until 1915 and an inspection team was sent on a tour of foreign submarine builders, principally Laubeuf and Laurenti.
The net result of these investigations gave the Admiralty the choice of placing orders for two foreign designs or returning to Vickers. The
Laurenti submarine, being built by the Fiat Company, was of the high buoyancy type, with 60% reserve buoyancy, and the initial report of the inspection team was favourable. Keyes persuaded the Admiralty to order one submarine of this design from Scotts of Greenock, 'as a first step towards terminating Messrs. Vickers monopoly which so far as our type of
submarine is concerned, binds us until March 1915. '19 The 'S' class, of which three were to be built, were the first double-hulled submarines in 20 the Royal Navy. 'S. l' was not completed, however, until after the out- break of the First World War and by then it was clear that this type of
submarine was unsuitable for operations in the North Sea. It is difficult
to reconcile the ordering of this and the Laubeuf design, since the need was for submarines of the overseas type, not of coastal displacement and
endurance. Further, neither the IS' or the 'iii' class21 (Laubeuf design) were able to operate in the winter conditions of the North Sea and were
finally sold to Italy during 1915-16, where they proved more suitable for
Mediterranean conditions. The Laubeuf submarine, with 46% reserve buoyancy, was the product of the Schreider works at Toulon. Initially,
the inspection team gave this design a negative report but the Admiralty
the decided, on recommendations of the Controller and Third Sea Lord, -
19. Keyes to Third Sea Lord, 12 Sept. 1911, AD14 158/404B, C. N. 2424/11, N. M. M., 'Report from Commander Addison on a Fiat San Giorgio Submarine. '
20. See Appendix: D(7).
21. See Appendix: D(8). - 18 -
Admiral Moore, to order two of these submarines under licence from
Armstrongs because it was considered, 'desirable to get Armstrong as a
rival to Scott. '22 Keyes objected to this decision-considering them to
be, 'vessels of an unsuitable and somewhat obsolete design. '25 " However,
at the same time he admitted that he preferred to spend available financial
resources with Scotts, for a submarine based on similar design principles
to the Laubeuf boats. The 'W' class proved as unsuitable as the 'S' class
for North Sea patrols and were considered obsolete by the time they were 24 ready for service. However, as a result of a decision to-order six 'W'
class from Armstrongs, before the first two submarines-of-this type had
been completed, the Admiralty became ultimately committed to another
building monopoly. In addition, the final-cost of, the '1'V class proved to
be far in excess of both 'E' class submarines and, more damagingly, the
'S' class being built by Scotts.
Although the motives behind the termination of the Vickers contract
and the buying of foreign designs were sound, they failed to achieve the
desired objectives. The original idea had been to increase the quantity
and quality of submarine production, particularly the overseas type,
through the introduction of an element of competition. Measured in these
terms the final result can only be termed apartial failure, with the
Vickers being two monopoly merely replaced by small contract monopolies -
Scotts and Armstrongs. However, a measure of success was achieved in so
far as new firms were encouraged to undertake submarine design and
22. Admiral A. C. M. U. Moore, 14 Sept. 1912, Keyes MSS 4/1.
23. Keyes to Admiralty, 3 Nov. 1912, Keyes MSS 4/1, B86/1/12, C. P. 02534/1912.
24. ADM 1/8374/93, 'Submarine Engine Development' (See iVote 7). - 19 -
construction. In an attempt to clarify the situation the First Lord, 25 Winston Churchill, set up a Submarine Committee under the chairmanship of Commodore (S).; Roger Keyes. Their brief was to"evaluate existing submarine development and to recommend possible lines of future British submarine design and development. An initial cönclusion*was that in general Britain lagged behind France and Italy. However, the failures resulting from the purchase of continental designs led the Committee to concentrate on British designs, incorporating those'-aspects of the French and Italian designs they deemed most valuable. The Committee recommended the construction of two types of submarine; one similar to the 'C' class, but with alarger reserve of buoyancy, and the other to displace 1,000 tons with a design speed of twenty knots, to operate with the Fleet. In furth- erance of this objective the projected submarine was also to be'eap able of high submerged speed for short distances in order-to"attack the enemy battlefleet before the main engagement. The belief that-the submarine could function as an integral unit of the Fleet'was revolutionary only a decade after 'A. l' had been accepted into service. Nevertheless', while the production of the theory was relatively simple, the development of a submarine capable of fulfilling this role was--far more complex. However in 1912 the problem did not seem insurmountable-to the Submarine Committee.
Their solution was merely to increase the power'of'the largest submarine diesel engine available in order to achieve the necessary speed.
25. Churchill, Rt. Hon. Sir Winston Leonard Spencer (1874-1965); b. 30 Nov. 1874; First Lord of the Admiralty, 1911-15; Minister of Munitions, June 1917. -=Dec. 1918; Sec. of State for War & Air, Jan. 1919-Feb. 1921; Chancellor of the Exchequer, Nov. 1924-1May 1929; First Lord of Admiralty, 3 Sept. 1939; then Prime Minister and Minister of Defence; d. 24 Jan. 1965. - 20 -
26 Experience, in the form of the experimental submarines ! Nautilus? 27 (diesel) and 'Swordfish' (steam propelled), was to dispel the illusion.
Although orders continued to be placed for new coastal designs, principally 'F'28 and 'V'29-classes, there was a continuing shortfall in
in numbers of overseas patrol submarines, especially comparison with ,. _
Germany. Additional orders were placed for 'E' class submarines-but delays continued to be experienced with the design of its successor, the 30 'G' class. The first of these should have been included in the 1914-15 programme but the design was not completed until late 1914 and this delayed
entry into service until 1916.
Continuing delays in producing adequate numbers of overseas patrol
submarines partially reflected the conservatism of British. naval policy.
During the first years of the century the Admiralty, had seen the submarine
as suitable only for coast defence. This role was re-confirmed in 1911 as
part of the new dispositions against the growing threat posed by Germany.
This policy bore no relationship to the roles undertaken in peacetime
training or to the capabilities of the 'E' class submarines, then on order.
In Keyes's view this was because the belief continued to exist, within the
that the but, liable Navy, submarine was not only slow and unseaworthy, -was
to be surprised on the surface-at night or in poor light and sunk by
ramming or gunfire before it. could dive.. Keyes, supported by the Second
26. See Appendix: D(9).
27. See Appendix: D(10).
28. See Appendix: D(11).
29. See Appendix: D(12).
30. See Appendix: D(13). - 21 -
31 Sea Lord, Admiral Jellicoe, was convinced that the submarine could restore the concept of close blockade; an optimistic belief which over- looked the limitations in existing patrol submarine designs. An Admiralty study rightly rejected Keyes's view but conceded that if the enemy evaded the British Fleet then: 'It would rest with the British overseas submarines to endeavour to frustrate whatever object the enemy's main body might have in view. '32 In addition, the demise of close blockade created a need for a method of relaying information on the movements of enemy vessels to the surface forces maintaining a distant blockade. The submarine, with its ability to patrol unseen below the surface, was able to operate between the
Fleet and the enemy bases. However Keyes and other advocates of the offensive use of submarines nullified this concept by a rigid adherence to the belief that submarines should be used in groups, accompanied by a surface escort, and in co-operation with the Fleet. This theory, that the
British submarine could only gain acceptance by fulfilling a Fleet role, made no allowance for operations against enemy bases. Moreover, it ignored the fact that a surface escort destroyed the advantage of a surprise conferred on the submarine by its ability to submerge.
The defensive role assigned to the submarine was further confirmed by the fact that invasion remained one of the bogeys of British military planners. This resulted in the planned submarine dispositions being largely based on the need to counter any such threat. The Admiralty's
31. Jellicoe, John Rushworth, First Earl Jellicoe (1859-1935), Admiral of the Fleet; b. 5 Dec. 1859; D. N. O., 1907; Rear- Admiral (Atlantic Fleet), 1907-8; Controller, 1908-10; C. in C. Atlantic Fleet, 1910-11; C. in C. 2 Division of Home Fleet, 1911-12; Second Sea Lord, 1912-14; C. in C. Grand Fleet, 1914-16; First Sea Lord, 1916; C. N. S., 1917; Admiral of the Fleet, 1919; d. 20 Nov. 1935.
32. A. J. Marder, From the Dreadnought to Scapa Flow (O. u. P., 1961-70), 1,534-35. - 22 -
plan included using old destroyers with the coastal submarines but the
1913 manoeuvres confirmed the difficulties of defending a long coastline and. raised the question: 'Whether our present disposition of submarines is best suited for defence of the coast from military raiding expeditions. 'oo
The question of the offensive use of submarines was also raised:
'The success of the submarine during the manoeuvres makes it necessary to give to consideration ... what offensive plans are likely to be most effective for oversea operations by submarines. '34
This support for freeing the submarine from its defensive role was eagerly
seized by Keyes, who stressed the futility of this role:
t If the defence of the coast is to be left to they in submarines ... must be sufficient number to enable some to be at every possible landing place, when weather permits of a landing, and unless they are able to attack the transports in fairly deep water it is doubtful whether a landing will be frustrated. t55
Meanwhile, the overseas submarine was projected as having two possible
roles, in addition to its anti-warship function. However, the ability to
fulfil the roles of fleet reconnaissance and blockade were, in the Admiralty's 36 view, dependent upon further improvements in both speed and endurance.
In contrast, Admiral Fisher continued to expound his belief that the
submarine.: '"was the perfect naval weapon, capable of causing wholesale 57 destruction to an enemy fleet and restoring the strategy of close blockade.
33. C. in C. Home F1eetm to Admiral de Robeck, 6 Aug. 1913, ADM 157/1926., H. F. 0306.
54. Ibid.
35. Keyes to de Robeck, 14 May 1914, ADM 1371926, M. 0713, 'Report of Findings of Admiralty Submarine Committee. '
36. Ibid.
37. J. A. Fisher, Memoirs. (London, 1919), 181-85. - 25 -
Such extreme optimism, however, damaged the development of the case for a realistic acceptance of the submarine based on an objective evaluation of its capacity. Equally it was dangerous if such views caused the submarine force to be committed to roles it was either inexperienced or unsuitable- for: 'Such optimism is not shared by those who have worked-in and with submarines during the last three years. They are not inclined to exaggerate 58. their powers, and are quite alive. to their limitations. ' The overriding factor in all these deliberations on future roles was. the problem of insufficient numbers. Despite his previously enthusiastic advocacy for the use of the-submarine in an offensive role, Keyes recognised that the existing shortage of overseas boats restricted the ability. to fulfil such roles as reconnaissance in enemy waters:
'As a result of recent experience and much - I the consideration am strongly of opinion ... that these vessels should not be sent into the Heligoland. Bight, at any rate in the early stages of a war, until we have many more available. 'ý9
Even in the anti-warship role, the limited number of overseas submarines available meant that it was difficult to turn a potential threat into a damaging physical threat. Only with the advent of the 'Dt and 'E' class submarines had there been a gradual acceptance of the capabilities of this type. Revision of policy was not quickly reflected in construction, however, and the period 1910-1914 largely saw a continuation of the coast and part defence role as the prime duty allocated to the Submarine Service.
Plans were well advanced for a gradual replacement of the defensive mine- -ý" fields around British harbours by coastal submarines, resul, ting in 1914 in the bulk of British submarines possessing limited endurance.
38. Keyes to de Robeck, 10 Aug. 1913, ADM 137/1926.
39. Keyes to de Robeck, 21 Aug. 1913, ADM 157/1926) B. 02/4. - 24 -
Nevertheless, submarine development had progressed sufficiently for the Admiralty to draw the conclusion that if the German Navy's submarines had been developed to at least the same level as the Royal Navy's then . submarine warfare could no longer be regarded. as purely defensive Despite
this, by 1914 the Royal Navy still possessed: 'No effective means of
direct attack on the submerged submarine. '4" The acceptance that limited moves such as high speed and zig-zagging courses by the Fleet were
necessary was a tacit admission of the growing importance of the submarine
in naval warfare. However, a myopic attitude still existed that the
capital ship was inviolate: 'It is very difficult to make people think in
anything but terms of dreadnoughts. It is a perfectly hateful idea to
senior officers of the Navy that a submarine should dominate waters in 42 which dreadnoughts proudly sail. ' This attitude was clearly manifested
in Fleet manoeuvres where:
'Even in the Service the full significance of the submarine menace is not generally recognised. To the battleship or cruiser, a submarine attack is an interesting exercise, partaking rather of the nature of a set piece; perhaps two or three hours are devoted to it, but the atmosphere is unreal, there are probably destroyers about to pick up the torpedoes, or a convoy with the submarines for the purpose of warning off the ordinary traffic, ' (and), 'as often as not the direction of the attack is more or less known. ' `5
40. G. Smith, Britain's Clandestine Submarines, 1914-15 (London, 1964), 15-16.
41. Keyes to Admiralty Submarine Committee, May 1914, AD,,1 157/1926, M. 0713. See also: C. in C. Home Fleets, Admiral Callaghan, 19 July 1914, Keyes MSS, KYS 4/18, 'Remarks on Submarine Defence generally. '
42. 'The Influence of the Submarine on Naval Policy - 1', Naval Review, 1,1915,147. -
45. 'The Influence of the Submarine on Naval Policy - II', Naval Review, 2,1914,48-49. 25
Nevertheless, the supporters of the capital ship had one valid line of reasoning which could not be broken down. Submarines, in 1914, might have been considered by some to have replaced the surface vessel in winning control of the sea. However, submariners were among the first to admit that the submarine lacked the power to exercise this control and its limit- ations were insuperable to the extent that it could not replace the surface warship in every role. Moreover, the ability of the submarine to fulfil some roles was hampered by the continuing shortage of numbers and any opportunity was seized-to-expound the disadvantages of failing to rectify this:
'Until we have a great many more submarines in commission, the submarine menace to an enemy will be more moral than real, particularly on the high seas or at a distance from base. The moral effect should certainly be great, for -one can never fehl secure from attack, but the field of operations is large, casualties and breakdowns are certain to be numerous, and numbers are essential, if offensive operations are to be maintained. ''`'
The most effective place to deploy submarines was off enemy ports and naval bases but this was also where the heaviest' concentration of anti-submarine (1!,/S) forces were. If the submarine was to be allowed to undertake offensive operations then these could only be successful if such forces were available in adequate strength.
On the eve of the First World War the Royal Navy was still divided on the value of the submarine. The Submarine Service was supported largely by junior officers in its attempts to shed the belief that this type of vessel should be restricted to defensive roles. Pre-war manoeuvres had
shown the submarine's ability to be more than a harbour-defence boat, but
senior officers remained less than enthusiastic. Those who favoured the
44. Keyes, 55. - op. cit., - 26 -
continued supremacy of the capital ship were also divided into those who regarded the submarine as, at worst, a nuisance and suitable ctnly for local defence and, at best, those who tended to exaggerate the power of the submarine to decimate a surface Fleet. Commanders, such as Admiral
Jellicoe, who had used submarines to such good advantage in pre-war manoeuvres, were now to allow isolated successes to grow into a belief
that even sporadic use of the submarine by an enemy could reduce the
Home Fleet to a size where the enemy could chance challenging it with his
own surface vessels. This attitude was to dominate Fleet strategy and
tactics throughout the War to an extent out of all proportion to the true
threat.
What could not be denied, if the submarine was to be considered as a
direct alternative to the surface warship, was the submarine's disadvantage
in speed and endurance. The latest overseas patrol submarines were only
capable of 14-15 knots on the surface and 8-9 knots submerged, compared to
the battlefleet's speed of over 20 knots. Despite this it was held that:
'It 'is perfectly feasible for submarines of the "E" to fleet to class accompany a sea, and ... they 'would. be able to keep the sea for several days. They might prove invaluable to an inferior force and might well be placed in a position to do considerable damage to some of the units of a superior hostile fleet. It is more difficult to see how they could be brought in contact with the enemy, should he be endeavouring to avoid an engagement, but it is conceivable that he might be induced or forced to alter course towards the submarines. t45
Nevertheless, the desire to operate British submarines with the Fleet
depended on the ability to produce a means of propulsion which could offer 46 the extra surface speed necessary. This'problem, however, was considered
45. Keyes to Admiralty, Aug. 1914, ADM 137'1926.
46. Keyes, March 1912, Keyes MSS 4/5. - 27 -
by the Admiralty to take second place to the need to increase the-number
by-the of overseas patrol submarines. The result was a conference, called
1?irst Sea Lord, on 9 December 1913 which decided to devote the majority of
to the money available for the 1914-15 submarine programme production of- the overseas patrol model.
These included an improved version of the 'E' class, known as the
Admiralty 'E'. This had a double hull, internal sub-division, increased habitability and greater buoyancy reserve. The overall effect was to'
increase-endurance and operating efficiency, especially on long patrols.
Both this and the 'G' class design retained beam tubes, due to the Admiralty's belief in the value of'such torpedo positioning despite the knowledge that
similar sized French and German submarines attacked without beam tubes;
'At the time, our submarine officers undoubtedly placed an exaggerated
tactical value on the possession of broadside tubes and were ready to make
sacrifices in other directions in order to have them. r47
In August 1914 the bulk of the 76 submarines in service were still of
the 'B' and 'C' classes of coastal boats. Only the 'D' and 'E'- class
submarines were capable of operations other than local defence, but
insufficient numbers of these types during the early months -of , the War
necessitated the use of coastal submarines for patrols off areas such as
the Belgian coast. Moreover, construction delays meant that the Royal
Navyy - entered the filar committed initially to the original 'EI class as the
basic overseas patrol submarine.
The Admiralty, as a result of a conference on 9 November 1914,
ordereda further 57 submarines and this large number necessitated the
47. Admiralty Technical History, Vol. 3, Part 21, 'Submarine Administration, Construction and Training, ' 24. -28-
Although use of many shipbuilding firms new to submarine construction.
Vickers had dramatically improved their production facilities and. reduced
the construction time for the 'E' class from twelve to eight months,
wisdom of the, decision to end the Vickers monopoly so as to introduce new
firms was clearly if belatedly vindicated. Proposals had to be considered,
however, for increasing the speed of production among these firms and
principally to. reduce the construction time of some submarines from twenty
months to a possible eleven months. This was finally achieved through
strict co-ordination by the Admiralty of the various firms involved in
supplying components and engines to the shipbuilders. Solutions were
ordered to be drastic irrespective of existing contracts. Thus:
'if building "E" type hulls, instead of "G", will reduce time of construction by ever so this be done; short a period, will and ... no questions of design will be involved when boats firms copying existing ... The competent to build. should be sent for, given the drawings and all other necessary information and told to go straight on with the work with all possible despatch. '48
However, despite the increase in the number of shipbuilding firms, the
maximum number of submarines which could be produced was still considered
inadequate. The result was the signing of a contract with an American 49 firm - Bethlehem Steel Works -. to build twenty 'H' class submarines.
Meanwhile, further alterations to the I GI design added to the delay
in bringing this new patrol submarine into service. In this instance a
last minute decision was taken to double the torpedo armament, since war
experience showed that larger salvoes were needed to ensure a hit. This
was an implicit criticism of the pre-war attitude of the Admiralty and the
48. Fisher, 5 Nov. 1914, ADPM1/8402/419, 'Additions to 1914-15 Submarine Building Programme. '
49. See Appendix: D(14). - 29 -
Treasury which had severely restricted torpedo firing; practice. Moreover, in addition to the time delay, the design changes were calculated to result in a loss of 12 knots surface speed. Previously it had been confidently held that: 'We are in sight of an eighteen knot submarine in the near future. Slow speed on the surface constituted the former weakness of these 50 craft for such work. '
In an attempt to return to this position while retaining a patrol
capacity, the Admiralty decided to proceed with another new design. The
'E' class had shown the usefulness of overseas patrol submarines in the
reconnaissance, as well as the anti-warship, role. ' However, the hope was
that the latter duty could be expanded by the addition of greater speed
which would also contribute to the ultimate goal of a fleet role. Initial
developments concentrated on merely adding four extra cylinders to the
800 B. H. P. engines of the 'E' class and thereby producing a 1200 B. H. P.
unit. The new high-speed design, known as the 'J' class51 was to be
fitted with three of these units, while retaining the increase in torpedo
armament fitted in the 'G' class. Designs were completed by January 1915
and eight of this class were ordered. Sea trials indicated problems in
the flooding system which brought the submarine down by the head in a sea-
way and reduced its surface speed. The alterations required included the
raising of the bow and the fitting of a curved upper deck forward. This
enabled the 'J' class, 'to maintain a speed of 17 knots in the heaviest 52 seas', but this was no improvement on the 'G' class and well below the
battlefleet's speed. Tardily it was recognised that development of a
50. De Robeck to'C. in C. Home Fleet, 29 Aug. 1913, ADM 137/1926,0.154.
51. See Appendix: D(16).
52. Admiralty Technical History, 5,21,27. - 30 -
fleet submarine would only come from specialist craft divorced from the ability to undertake long range patrol duties. Confirmation of this view was given by the Submarine Development Committee, set up by the Admiralty in September 1915. The overall brief was to examine the efficiency of the existing system for deducing future submarine requirements. Although
(S) Commodore was appointed as a member of this Committee, the practicality of its conclusions was handicapped by the predominance of non-submarine 55 officers headed by the chairman, Admiral Tudor, the Third Sea Lord.
This led to the Committee initially concentrating on known submarine types, especially coastal and overseas patrol submarines. In the case of the former, apart from the 'B' and 'C' classes which were considered obsolete, the committee concluded that this type was still suitable and essential for operational duties. The attitude was largely engendered by the
fear continuing of a German invasion and: the usefulness of such submarines in this role, despite their failure to prevent naval bombardments of the
England. East coast of Nevertheless, the coastal submarine could be seen
having as some value in the short range patrol role but the most practical
have been approach would a determined policy to replace them with overseas patrol submarines. The question of cost''would have had to be considered but in although a standard problem peacetime would have been less so in war. in their However, recommendations the Committee strangely adopted an optimistic view and even considered the coastal types as being suitable for patrol duties in the Heligoland Bight.
53. Tudor, Admiral Sir Frederick Charles (1865-1946); b. 29 liar. 1863; D. N. O. T., 1912-14; Third Sea Lord and Controller, 1914-17; C. in C. China Station, 1917-19; d. 14 Apr. 1946. - 51 -
The prime role of the overseas patrol submarine remained the-destr- uction of enemy warships but reconnaissance was rapidly increasing in importance. Although the Committee recognised the importance of these two roles it decided to recommend the division of patrol areas into coastal and overseas with the equivalent type of submarine being' considered to have the prerogative on attacks in their area. This would have produced a confused situation in which an overseas submarine would have-had to refrain from attacking an enemy warship if the latter was judged. to be within the coastal area. Fortunately the Admiralty did not accept this recommendation but it does reflect the level of over-elaborate and confused thinking which characterised much of this body's work. -Thus 'D', 'U', and
'G' class submarines were considered suitable for operations off the enemy coast, while the 'J' class were to be retained in home ports. Using their higher surface speed they were then to rendezvous with the Grand Fleet.
This reflected the persistent belief that the submarine could not be - considered as a major naval weapon unless it were capable of-operating with the Fleet. However, the maximum speed of the 'J' class was still, insuff- icient to allow them to maintain station with the Fleet-and the Admiralty remained lukewarm towards this suggestion. Nevertheless, pressure for a fleet submarine was increasing and advocates included Admiral Jellicoe, now
C. in C. Grand Fleet. Opposition remain strong and influential:
'It is not yet certain that high speed will always tactical carry advantage ... Generally speaking, in submarines the power to submerge takes the place of high high-speed speed . o. A submarine will have many disadvantages. Her length makes her a great target for torpedo attack. Her visibility makes her easier to stalk by hostile submarines. It is true that high speed enables her to zig-zag and renders her more diff- icult to hig, but the balance is considered to leave her with a disadvantage. Underiater she is made unhandy to manoeuvre quickly for torpedo attack and she requires deep water to work in. She is more likely to strike mines, on the surface and submerged. She is also more costly and a much greater anxiety to the personnel. '54
54. Admiralty Technical History, 21,14-15. - 32 -
Despite this catalogue of woe the Committee remained prepared to recommend development of a fleet submarine.
Fleet Submarines 1914-18
The lack of a sufficiently powerful engine had prevented the pre-war production of a fleet submarine since the most powerful diesel engines were unable to produce the necessary speed. The possibility of using
steam propulsion was proposed by the D. N. C., -Sir Eustace Tennyson 55 d'Eyncourt, to the Third Sea Lord in November 1913 along with a design
for a fleet submarine of 1660 tons displacement and a surface speed of 56 24 knots.
Surface power was to be provided by steam driven geared turbines,
similar to the installation proposed for the experimental submarine 'Sword-
fish' but of much greater power (10,000 B. H. P. as against 3,250 B. H. P. ).
Armament was to be integrated into the hull design to the extent that the bow and stern torpedo tubes were to be slightly angled (6° forward, 10°
aft) from the centre line in order to allow better arrangement of the hull
than attainable with direct ahead or-astern fire. Sufficient space was
considered to be available to fit 21 inch beam torpedo tubes instead of
the 18 inch being fitted in existing construction. Additional proposals
included a thin belt of armour on the superstructure around funnel hatches,
engine room ventilating trunks and gun positions because of the'time requ-
ired for-, the submarine to close down its boilers and-dive..
The use of steam turbines in submarines, especially in continental
designs, had this earned form of propulsion a dubious reputation and not
55. D'Eyncourt, Sir ustace Henry William Tennyson (1868-1951); b. 1 Apr. 1868; D. N. C. and Chief Technical Adviser to the Admiralty, 1912-25; d. 1 Feb. 1951.
56. See Appendix: E(1). -. 55 -
surprisingly it was decided not to proceed further with the D. N. C. 's design at that time. Other objections centred on the large increase in displacement and size. These increases were seen as posing problems of control and manoeuvrability underwater. Keyes preferred to approach the development of such a submarine by getting experience with the experimental
'Nautilus'. However, the slow progress on this boat, which practically stopped after the outbreak of war, led to the dropping of this condition.
Meanwhile, Fisher directed the D. N. C. to produce a high speed submarine design based on diesel propulsion, despite the latter's. reiteration. that
a speed of approximately 22 knots could only be achieved by, using. steam turbines. Existing diesel engines were considered to be only capable of
15-16 knots but Fisher remained adamant that steam propulsion was not to 57 be used in the new submarine. After intensive development the first of the 'J' class achieved 19 knots, which although an outstanding achievement was clearly insufficient to qualify for fleet submarine, status. However,
the design pending of a faster boat it was decided to order a further _ 'J' eight class. Meanwhile, undeterred by the. failure to produce a
22 knots submarine, Admirals Jellicoe and Beatty58 continued to insist that the 'J' class and existing patrol submarines could. and should operate
the. with Fleet, even if this meant resorting to a rendezvous system.
1915 Throughout pressure continued to be applied to move part of the
8th Submarine Flotilla from Harwich to the Tyne, in order to carry out a 59 tactical role with the Fleet.
57. D. Everitt, The K. Boats (London,. 1963), 25.
58. Beatty, David, First Earl Beatty (1871-1936), Admiral of the Fleet; b. 17 Jan. 1871; C. in C. Grand Fleet, 1917-1919; Admiral, 1 Jan. 1919; First Sea Lord, 1 Nov. 1919-1 July 1927; d. 11 March 1956.
59. Admiralty to (and versa), Jellicoe vice July 1915 - Mar. 1916, ADM 137/1926. - 34 -
The Submarine Service continued to regard their primary-role as the destruction of enemy warships, even if co-operation with the Fleet was not considered as the sole means of achieving this, and there was no aversion to the production of a fleet submarine. The actual use of"such boats in a'surface action, however, was not viewed, with the same equanimity. Foll- owing-the 1913 Fleet exercises, Keyes had confessed to having had, 'some very bad moments watching heavy'ships, cruisers and destroyers manoeuvring 60 in all directions over the submarines. ' There was also the danger from
British warships attacking their own submarines in mistake for those of the enemy in the confusion of a battle where any periscope was likely to be treated as hostile. The belief that the Germans possessed fleet subma- rines encouraged the opinion that unless the Grand Fleet was similarly
it 'be disadvantage equipped would, at a great ... against the German battlefleet. '61 The result was'a resumption of development of the fleet submarine, and acceptance of the fact that to achieve the required surface speed, steam turbines would have to be used. Although Vickers submitted
decision designs the final was in favour of the design originally presented
the 800 by D. N. C. An B. H. P. auxiliary diesel generator was'added to enable the submarine to continue underway while changing over from steam turbines to electric motors and vice versa. This also enabled the boat to dive more rapidly. Time was saved on construction by using existing 18 inch
tube designs ('J' bow class) and 18 inch beam tube designs ('E' class).
The gun armament was to consist of two 4 inch and one 5 inch. H/A_but the
inch 4 were replaced by 5.5 inch in the last three of the class. Completed designs for the 'K' class were approved in April 1915 and preliminary orders placed in June.
60. Keyes to de Robeck, 10 Aug. 1913, ADM 157/1926.
61. Jellicoe to Admiralty, 8 Nov. 1915, Naval Staff Monographs, Home Maters, Oct. 1915 - May 1916, 31 (1926), VC, 25. - 55 -
In-July 1915 work began on an extensive review of the necessity for
future 62 existing and submarine construction programmes. A major aim gras. to prevent any breakdown in the supply of parts and machinery to the ship- builders because of the increase in orders. Submarines under consideration for future-construction were divided into three types. Sufficient coastal
overseas and models were considered to be available or building to meet
for requirements the expected duration of the'War. The former were not to be replaced as they became obsolete and the overseas models were planned to'reach a total of 82 boats by July 1916, exclusive of war losses. If losses proved tobe higher than calculated, replacement orders were to be
'G' mainly class. The only model not to be limited in numbers at that time 63 was the 'K' class, of which only four had been ordered by July 1915.
Authorisation was given for further construction, with orders being placed from August 1915. A major motive behind the procuring of the fleet model to be continued a desire not to be deficient in a weapon, which the Germans
believed'to were possess; 'There is no doubt that we are behind the Germans in this type `of Submarine the future and as of naval submarine warfare will in lie this type all-probability with of vessel, our numbers should certainly be-increäsed. '64 planners Naval were prepared to see the need for fleet
have this belief submarines and reinforced by deductions about enemy subma-
developments tactics rive and which were largely a reflection of their own tactical thinking.
62. Admiral Tudor, July 1915, ADM 1/8428/209, 'Review of Future Submarine Programmes. '
65. See Appendix: D(17).
64. ADM 1/8428/209, 'Review of Future Submarine Programmes. ' (See Note 62). -36-
The 'K' class were intended primarily to operate with the Battle
Squadrons of the Grand Fleet and total numbers were based on this require- ment which indicated the need for fourteen boats, allowing two for each
Squadron plus four in reserve. The total cost for the extra ten submarines was assessed as 93 million. Authorisation had already been given for work to start on the auxiliary generators for the additional boats, and contracts were placed with selected firms on the basis of a twelve months completion target as the need to bring these submarines into service was considered urgent.
meanwhile, Fisher had resigned as First Sea Lord on 17 May 1915. The degree of his influence on fleet submarine development stemmed largely from his single-minded pursuit of a definite course of action and his ability to pursue it relentlessly to a conclusion irrespective of alternative opinion. Equally he could obstruct a line of development as determinedly, and only extreme pressure or necessity could cause a change in either course. Possibly, in the case of the fleet submarine, Fisher may have been stung by the criticism, from Keyes and others, that he had neglected the development and construction of the overseas patrol submarine in favour of the coastal model, especially as the Germans had done exactly the opposite and were being proved right by wartime exp erience. However,
Fisher did apparently expend considerable effort to ensure a rapid wartime, increase in the numbers of overseas submarines. Similarly, the 'J' and 'K' classes, on which Fisher altered his attitude, attest to a single-minded desire to expand the offensive role of the submarine, something he had advocated since the earliest years of submarine development.
Construction of the early 'K' class did not proceed smoothly, requiring several design changes. However, the overall design had been expected to cause problems because of the size and complexity of this type of submarine. Major difficulties were encountered at an early stage of - 37 -
construction, especially over the requirement that the funnels and air intakes to the stokeholds had to be capable of being closed rapidly if the submarine was to be able to submerge within the design time of five minutes. The D. N. C. and E. in C., working in collaboration with specialist firms, managed to solve this problem principally through use of watertight doors. Then there was the problem of the effect of fumes from the boilers when diving. The solution to this difficulty was based on the construction of a passageway past the boiler room, thereby isolating this area on diving but still allowing free access to the fore and aft sections of the hull. In order to ensure as high an underwater speed as possible, the superstructure had to be streamlines as far as the overall size, armament and propulsion system allowed. Therefore, provision had to be made for the two funnels to be hinged down into the superstructure before diving.
The holes were to be covered by hinged doors fitted with india-rubber sealings to ensure that the hull was watertight.
A total of 27 'K' boats were ordered before November 1918, the first boat ('K. 3') being in completed September 1916; but with the Battle of
fought the Jutland already chance was missed to test this type of subma- rine in the role for which it had been designed. Despite this, two flot- illas formed were and attached to the Grand Fleet. During sea trials the design 24 knots speeds of surface and 9 knots submerged were achieved.
However, their length in great relation to their beam, and the type of hull, designed for high speed on the surface, made these boats very slow in diving difficult to and manoeuvre underwater. The small size of the hydroplanes, to compared the hull size, also created a danger since there was a tendency to 'nose-dive' if the submarine was not handled carefully during diving.
The last months of the War saw the 'K' class being used as patrol submarines as another fleet action became increasingly unlikely. They were - 38 -
not entirely suited to this role, for which they were an expensive product
compared to the 'E' or 'L' classes. Their relegation to this tole tended
to reinforce the feeling that the 'K' class absorbed a disproportidnate
amount of resources and skilled manpower compared to the overseas patrol
submarine. The latter was considered to have made a greater contribution
to the War, and resulted in support for fleet submarines being at a low
level by 1918. Nevertheless, on the question of design they were a
remarkable achievement and illustrated how quickly submarine design could
be developed when high level support and adequate resources were available.
The design concept of the fleet submarine had demanded that-it should
possess a surface speed of at. least 2 knots in excess of the fastest
capital ship. This was to enable it to proceed ahead of the Fleet and
attack the enemy before the main surface action began. Steam turbines
had given the 'K' class a maximum speed of"24 knots but by 1918 this was
well below the speed of the battlecruiser force and, at best, barely
equalled the speed of the battlefleet. However, the fastest diesel
('J' engined submarines class) were-only. capable of 19 knots. The surpr-
ising factor is not that the 'K' class- should have been considered, 'a
wonderfully successful experiment', but that it-should have been concluded
that, 'the employment of submarines in a fleet-action was a natural develop-
ment of submarine warfare', especially as-the same writer held that there
was, 'the danger of torpedoes hitting friendly ships in a close action. '65
moreover, to the risk of being attacked by their own surface ships was
added the problem of destroying enemy ships without being rammed, due to
the frequent changes in speed and course that all surface ships were obliged.
to pursue during a battle. An added problem in justification was caused.
65. 'The Employment of Submarines and their Future Development', Naval Review, VIII, 1920. - 59 -
not only by the post-war discovery that the Germans had never intended to build fleet submarines to accompany the battlefleet but also on the more general level of policy because from November 1918 there was no longer a
German battlefleet.
Cruiser Submarine
During 1915 proposals were also considered for a cruiser submarine.
Although such a model was considered essential by some members of the
Admiralty Submarine Development dommittee the lack of targets and roles for such a boat did not indicate an immediate requirement. Nevertheless, there was considered to be a possible future use in a blockade role and it was proposed that design work should be initiated. The D. N. C. pointed out that a reduction in design speed of 4 knots in the 'Kt class submarine would make it possible to adapt this design to the cruiser role. The speed reduction was expected to allow an increase in displacement without
altering the length of the submarine. In addition, the endurance could be increased from 5,000 miles at 10 knots to 10,000 miles at the same speed.
Battery power could be extended to 24 hours before the need to recharge
and allowed twelve hours at submerged speed.
On the question of armament, the gun was to predominate over the
torpedo. The British had previously paid little attention to gun armament
in submarines. The absence of commerce targets, and the known vulnerab-
ility of the submarine on the surface, dictated tactics based primarily
on the torpedo attack underwater. Those submarines which carried a deck
gun as part of their armament did so, with the exception of the 'K' class,
officially as a means of defence and not as an alternative to the torpedo;
as this would have necessitated arming all submarines with deck guns.
Nor, in 1915, did Admiralty policy accept that roles such as AIS patrols
were realistic proposals. Despite these conditions, initial proposals
for a cruiser submarine favoured a heavy gun armament, centring on the - 40 -
6 inch calibre. Further evidence of the intention that this type of submarine should fight on the surface, as well as underwater, was prov- ided by the inclusion of armour in determining the surface displacement.
Further discussions on the proposed design resulted in a decision to increase the gun calibre to 7.5 inches, although this meant that fewer
shells could be carried. A surface speed of 20 knots on diesel engines was hoped for but the existing limits of technology were against this.
Nevertheless, the Committee continued to adhere to the simplistic but
erroneous view that higher speed could be achieved merely by increases in
engine size rather than efficiency. Surprisingly, in view of known
evidence, the D. N. C. was even prepared to advance the idea of a 50 knot
submarine but this seems to have been largely a propaganda exercise to
retain support for the cruiser submarine concept in the face of growing (S)o opposition from Commodore The latter's doubts as to the wisdom or
necessity of building such a submarine had been reinforced by the sea
trials of 'K. 3'. The latest proposals of the D. N. C. had been to present
the cruiser submarine as a submersible warship capable of engaging enemy
surface warships up to and including the light cruiser category.
This role was seen as necessitating high speed and Commodore (S),
S. S. Hall, who considered the 'K' class, 'a very bold advance in subma- 66 rine design', was firmly of the opinion that such a design was a step
into the unknown. He doubted the efficiency of steam propulsion systems,
particularly as they affected rapid diving capability and the time to
return to full power on resurfacing. However, the main doubts concerned
the credibility of high speed in submarines:
66. Admiralty Technical History, 3,21,14. - 41 -
'High speed in the case of surface. vessels has always brought with it tactical advantage and in the case of the "K" class it is a necessity, because they are built to accompany the battle fleet. It is not yet certain, however, in the case of submarines that high speed will always carry tactical advantage with it. These advan- (1) tages are considered to be: - Enemy can be brought to action. (2) Action can be avoided. '67
However, in the latter case, the submarine had no need to use speed to avoid action since the existing range of A/S weapons enabled it to escape retribution by submerging. Moreover, Hall remained adamant that submarines were unsuitable for the surface combat role since:
'a 28 knot submarine cannot bring a light cruiser to action, she cannot on account of fire control and spotting difficulties engage in an action on the surface with her under any circumstances; on the majority of days she could not even man her 68 guns at 28 knots. '
Overall, opinion was against the concept of a high speed cruiser submarine on technological grounds and the absence of any foreseeable role for this type of vessel in British naval tactics. The result was a suspension of any further work, so that resources could then be allo- cated to the, 'consideration of designs of submarines of moderate size. '69
The Admiralty agreed that there was a greater need for submarine war prod- uction to be concentrated on the overseas patrol model. The decision against the cruiser submarine was reconfirmed early in 1918:
'it did that there not appear ... was any apparent for this the need class, of vessel ..., at present time the ... adoption of a programme for this class of vessel would be at the expense of the programme of submarine construction. '? O
67. Ibid.
68. 'Employment of Submarines', Naval Review, op cit.
69. 'Employment of Submarines', Naval Review, op cit.
70. D. of P. to operations Committee, 2 Feb. 1918, ADM 1/8564/210. - 42 -
The German submarine campaign was emphasised as being the Admiralty's main concern and all designs were to be assessed on their relevance to counter- ing this threat. The construction of a cruiser submarines was considered to:
'involve the retarding'or sacrifice of other types is known importance is whose utility and whole vital ... larger cruiser submarines vrould not be of great value in their effect upon the submarine campaign, either in direct offensive against submarines, in 'operations tending to obstruct their egress, or in escorting merchant ships, 'while the tactical advantages of such a vessel When used with the Fleet are to a great extent neutralised by the length of time which she would require to submerge and her slow speed and unhandiness when 71 submerged..
Nevertheless, the advent of German cruiser submarines in the North Atlantic
during 1918 ensured that there would be a resurrection of interest in the
early post-war years. An additional factor arose from the survival of the
desire to take the new but proven concept of the submarine and extend it
to other categories of warships; to produce in fact submersible versions
of surface vessels. The necessity of success in wartime had provided the
groundwork of this development and the impetus carried over into peacetime.
Although both the cruiser and fleet submarines were to prosper for some
time, other designs were to founder in the harsh environment of peace,
and the monitor submarine proved to be such a case.
Monitor Submarine
The monitor submarine was the last of the six models examined by the
Admiralty Submarine Development Committee and stemmed from the apparent
inadequacy of British torpedoes in the early stages of the First World War.
Allied to this was the belief that a gun armament might be more accurate
over long distances. Prior to the War, torpedo practice had been based
on firings at extremely short ranges and at targets steaming slowly in a
71. Ibid. -43-
straight line. The advent of war conditions, with targets zig-zagging at high speed and protected by surface vessels, forced submarines to fire from extreme range. This led to demands for an increase in the accuracy of torpedoes over longer ranges and for more torpedo tubes to be fitted in submarines. The result was a standard six bow torpedo armament in all new patrol submarines. On the question of accuracy it was reported that:
'submarines find an increasing difficulty in bringing (1) off successful torpedo attack due to: - High speed and zigging course of enemy. (2) Comparatively low speed of torpedo and resulting errors due to wrong estimation of enemy's speed and course. No case is known of a ship-of-war being torpedoed when under way at a range outside 1,000 yards. The result is that opportunities of inflicting damage on the enemy have very often been missed, even though the submarine has been brought unobserved within a mile of them. ' 72
Although a high speed warship was considered to have a good chance of
avoiding a torpedo at long range, it was suggested that if a submarine fired a large calibre gun then there would be less time for the ship to
avoid the shell. Moreover, such a submarine was calculated as being able to carry more shells than torpedoes. General support existed within the
Admiralty for this view largely because of the, tuntrustworthiness of the 73 torpedo as a weapon, ' and despite the effects on underwater performance.
Putting the cart before the horse, the Committee set about finding reasons for producing this type of submarine and concluded that, 'when
drawings have the been prepared it will be possible to examine more closely the question as to the uses to which such a vessel could be put. '74 One use proposed was against targets in the North Sea where it was hoped that
72. Hall to Admiralty Submarine Development Committee (A. S. D. C. ), Sept. 1915, Admiralty Technical History, 3,21,13.
73. Admiralty Technical History, 3, 21, 13.
74. Admiralty Technical History, 3, 21, 10-12. -44-
the addition of a large calibre gun would give an added advantage of
surprise when the submarine went into action. If for any unforeseen
reason-the gun should fail then the torpedo armament would be available
for use. Thus, despite the apparent inefficiency of existing torpedoes
this armament was still to be incorporated in the design. Finally, as in
the case of the fleet submarine, the belief was that the Germans would
develop such a weapon and therefore the Royal Navy had to pre-empt them.
Gun calibre continued to be subject to dispute and proposals to use
this type of submarine in coastal bombardment as well as the anti-warship
role were greeted with scepticism since there were few areas where a
submarine could submerge and still be within range. Existing calibres of
coastal artillery were considered sufficient to destroy the boat if any
but the largest gun was fitted. The calibres proposed such as 6 inch or
7.5 inch were clearly inadequate to meet this condition, which restricted
choice to the 12 inch gun. Nevertheless, the D. N. C. was still instructed
to prepare alternative designs incorporating the different proposals,
although opinion was moving in favour of the 12 inch armament:
'The principles upon which such a gun armament are considered to be based are that the submarine qualities should not be impaired, and that. the gun, which takes the place of the beam torpedo tubes and high surface speed, should be used by day, when born torpedo attack is not reasonably certain, and in place of torpedo by attack night ... Lastly, as to the size and usefulness of a vessel so armed, it is considered that as in the Sea of Marmora and off the Belgian coast-opportunities are bound to occur, even though it is at the moment difficult to lay down her role definitely. '75 76 On this imprecise basis the Committee now prepared to select a design,
and consideration was given to the proposal to fit two 12 inch guns.
However, the final decision was in favour of fitting only one and the
75. ADM 1/8564/210, D. of P. (See Note 70).
76. Admiralty Technical History, 3,21, 12-13. - 45 -
total number of boats to be ordered was set at four. The Admiralty
the accepted Committee's recommendations but continued to give priority to construction of overseas patrol models. Therefore, it was not until
February 1917 that the first two monitor submarines were ordered from
18', Vickers. 'K. then under construction, was taken over for conversion 77 and renamed 'M. 1'. A similar procedure was subsequently followed in the
three ('K. case of other submarines 19-211). All four boats were to be fitted 12 inch with a gun taken from obsolete King Edward VII' class battleships. The gun could be fired either on the surface or submerged
the barrel with only gun and periscope above the surface. In this case the to (with gun was elevated 200 the ability to traverse 100 on either bow) the and submarine submerged to between ten and twenty feet. By means
foresight the of a on gun and slight lateral traverse, aim could then be taken by periscope. However, the need to load the gun on the surface
this restricted unique manoeuvre to one shot. If used in roles such as
bombardment this coast produced a very complex and expensive way of firing one shell.
'M. l' during was, commissioned April 1918 but construction of the
three other monitor submarines was delayed, 'since it was recognised that if the enemy employed similar submarines they could do far more damage to
than us we could to them. '78 Yet in 1915 the Submarine Development Comm- ittee had found the possibility of the Germans possessing such submarines
for Britain to build a prime reason monitor submarines. The successes of the U-boat 1916-17 had campaigns of clearly done much to alter the minds
Doubts to of naval planners. as the need for this type of boat were rein- forced by the growing awareness of the paucity of areas and roles in
77. See Appendix: D(21).
78. Admiralty Technical History, 3,21,30. - 46 -
which it could operate:
'The opportunity of using "M. l" in the North Sea appears to be very limited. Enemy trade is practic- ally confined to territorial waters, whilst the inherent vulnerability of the submarine to surface attack and inferiority in gun control will always tend to place her at a disadvantage with surface war vessels. She might put a destroyer or other lightly gunned vessel out of action by a surprise attack, but opportunities of meeting these at close range are practically limited to the Heligoland Bight and the vicinity of Zeebrugge, neither of which are suitable patrol areas for large submarines. '79
Bombardment of the German coast was also ruled out but as an extreme poss-
ibility it was suggested that '15. l' might be employed on A/S diving patrols.
At ranges inside 2,000 yards the first round was considered to have a tgood'
chance of hitting an enemy submarine but this depended on being able to
fire before the target dived. Another proposal was to operate the 11,4'
class in the Mediterranean but:
'The only possible objectives in the Mediterranean appear to be the Caltaro-North Adriatic communications or bombardment of Pola, Trieste or Callaro. With regard to the former it is ... not considered that this operation would give '1,1.1' a reasonable opportunity to use her gun and it is not recommended. The water to the South and Westward of Pola is. deep and it is probable that surprise bombardments of that port could be carried out. Trieste could be bombarded by direct fire, but the risk would be greater in this case as there is only about eleven fathoms of water in the vicinity. Attack on the submarine might be guarded against by supporting her with surface vessels outside the gun range of the ports. 180
This envisaged a complicated procedure requiring the submarine to with-
draw, after firing each shell, in order to reload out of gun range. If
surface warships were needed to protect the monitor submarine in this
circumstance then it would seem more logical and less costly to carry out
79. Plans Division, 22 Aug. 1918, ADfd 137/2709.
80. Ibid. - 47 -
a surface bombardment. It is not surprising therefore that the conclusion reached was that:
'There seems to be no strategical or tactical justification for "M. 1" and the question arises whether "M. 2", "M. 3" and "M,ß. 4", which were ordered to be completed by the spring of 1919, should not be altered or the labour and material diverted to other work. The main function of a heavily gunned submarine is to dispute the control of areas in which surface craft are unable to operate. These areas are the Baltic, the Sea or Marmora and Heligoland Bight which are practically closed to submarines. Even if submarines are required to operate as gun vessels in other areas, two 4 inch guns are likely to be much more effective than one 12 inch as mounted in "ti. l". It is recommended, therefore, that these, or possible 5 inch guns be mounted in 81 the later "M" class. '
Nevertheless, this question of alterations to the gun armament was ignored
and 11i. 2' and 111.31 were equipped with a 12 inch gun. However, by the
spring of 1918 the fear that discovery of '?Ml's existence would lead to
Germany constructing such submarines had finally resulted in its despatch
to the Mediterranean. If the intention was to hide 114.1' then the move
succeeded admirably since the submarine spent the remaining months of the
War without seeing any action. Fear of Germany constructing monitor
submarines did not lead to the cancellation of other units of the 'bi'
class, the decision being that:
'delivery of "1d. 2" and "M. 3" in the spring of 1919 be would satisfactory and ... they should be proceeded with in the ordinary course without special expedition. "M. 4" should be similarly dealt with, so that delivery may be obtained in the Spring though at a later date than "M. 2" and
The Armistice with Germany did not alter this view, although it was
decided not to complete 'M. 4', and the official verdict remained that the,
81. Admiralty Technical History (See Note 78).
82. Operations Committee to Admiralty, 10 July 1918, ADM 1/8564/210. -48-
"'1Q" class are new and-embody the idea of the heavy gun submarine and are the basis for the development of a future gun submarine. 185 The gun sub- marine was to have no future, however, nor could the use of the 'M class in the patrol role be justified as a reason for retention since a 12 inch
gun was not an essential requirement. Like the 'K' class, from which they were descended, the monitor submarines were defeated by the size and cost
stemming from their specialist role. As a replacement for more general purpose submarines they were clearly uneconomic and in the period of
retrenchment following the : jar the question of cost was paramount.
Reductions in numbers were necessary in all categories of warship and in
the case of specialist submarines the choice lay between the 'K' class
and the '1d' class. The deciding factor was cost and since the latter were
diesel engined their fuel consumption was less than the 'K' class many of
which were also due for major boiler refits, so the vote for retention
was in favour of the 'rd' class.
The monitor submarine had been designed and built when there existed
a belief in the long range gun as a more efficient and accurate alternative
to the torpedo for 1,000 1141 ranges over yards .-A major problem with the ( class stemmed from the fact that its 12 inch gun could fire, ne shell
submerged: this left it open to attack on the surface and constituted its
gravest weakness. Clearly the necessity for a, 12 inch gun for patrol
duties was dubious and the post-war relegation to this role was a final
acceptance of the submarine's inadequacy for its designed role:
'Setting aside the difficulties of construction which can doubtless be overcome, the question here is whether the advantages of submersion would counter- balance the greater vulnerability and the additional
83. Ibid. - 49 -
'weight required for resisting water pressure and for submerged propelling machinery, which would have to be sacrificed from the other elements df armament, protection, speed and endurance ... The capital ship must remain a surface ship. '84
Initially, in the post-war period, the 'ii' class was assigned to the amalgamated 1st and 2nd Submarine Flotillas, operating with the Atlantic
Fleet. Following further reorganisation in the early 1920's these subma- rines were assigned to the Reserve. '11.11 was lost in 1925 and 'M. 2' and.
'M. 3' were subsequently used as the basis of two experimental submarine designs - seaplane carrier and minelayer.
Patrol Submarine 1916-18
In the months following the recommendations of the Admiralty Submarine
Development Committee, the 'E' class proved to be the basic model on which patrol submarine design improvements were to be based. In February 1916, orders were placed with Vickers for two new designs, designated at 'E. 57' and 'E. 58' which were essentially elongated versions of the 'E' class.
However, their designation was altered to 'L. 1' and 'L. 2' and they became 85 lead boats of a new class. Displacement was increased by 200 tons and
(surface) a further 22 knots was gained by fitting twelve cylinder rather than eight cylinder engines. Battery power was doubled to give an extra
2 knot submerged while torpedo armament remained standardised on the
18 inch fitted in beam as well as bow and stern tubes. The original design had called for the inclusion of a5 inch deck gun but as a result of sea trials this was increased to a4 inch calibre. Operational experience 86 with the 'L' class led to a larger version, the 'L. 50' class equipped with six 21 inch bow tubes. The increase in torpedo armament had been
84. 'Employment of Submarines', Naval Review, op cit.
85. See Appendix; D(19).
86. See Appendix: D(20). BISL. LONDIN. UNry. -. 50 -
based on overall war experience which confirmed the advantages of firing
a spread of torpedoes as a means of achieving a hit over increased
distances. However, the meagre results achieved by the use of torpedoes
on A/S patrols had resulted in continued pressure for the fitting of
4 inch guns as armament, 'If a gun is required in submarines for this
inch 5 inch firing ten is purpose, a4 or about rounds per minute a ... 87 suitable weapon. ' The absence of surface targets and the growing
strength of the U-boat campaign led to more submarines being committed to 88 11/S duties from early 1917 onwards. The 'L. 50' class, as the latest
design, were fitted with two 4 inch guns, mounted fore and aft high on a
lengthened conning tower so as to increase the chance of a successful hit
on a U-boat before it could dive.
/S Submarine
Despite this and other measures, the success rate against U-boats
remained low and a major reason was considered to be the meagre underwater
speed of existing submarines; improvements in underwater speed were
expected to increase the number of opportunities and the time that British
submarines would have available to strike at their opposite numbers. Thus,
in 1.iay 1917, the D. N. C. submitted designs for a submarine capable of
15 knots submerged and intended purely for A/S duties. Following lengthy
discussions the agreement of Commodore (S) was obtained and the Board gave 89 its approval in October to proceed with the construction of the 'R' class.
Surface speed was sacrificed (72 knots maximum) to facilitate the building
87. Plans Division, 22 Aug. 1918,9DM 157/2709.
88. Admiralty Technical History and. Index, Vol. 1, Chap. VII, July 1919, 'A/S Division'. See also: Vol. 1, Chap. 1, Mar. 1919, 'S/}S v SA,11.
89. See Appendix: D(21). - 51 -
of this design which represented the only British attempt during 1914-18 to produce a 'submarine' rather than a 'submersible'. Nevertheless, none of this class were completed in time to prove themselves under operational conditions. Only 'R. 7' encountered a U-boat and although it was able to reach an attack position, it was unable to make a successful attack.
Overall, a weapon which had entered the Mar as a largely unknown and untried quantity was now considered by the Admiralty to possess not only a tactical but also a possible strategic influence. This was particularly true of its ability to penetrate enemy waters for sustained periods.
However, despite the successes of the overseas submarines, especially in creating economic damage out of all proportion to their numbers, the policy persisted up to 1918 of retaining large numbers of boats in the A,/S and sometimes coast defence roles. Nevertheless, those submarines most in contact with the enemy were from the overseas flotillas and there was a growing awareness of the difficulties faced by their crews. This applied particularly on patrols in enemy waters where dangers from mines, depth charges and aircraft were most intense. Even officially it had been admitted that;
'no other class of ship is called upon-to run the gauntlet of mines on the enemy's coast to anything like the same extent as the översea submarines. When surface ships go into enemy waters they do so as an operation, the actual period of exposure is short, and when the operation is concluded the force is withdrawn. 190
MSoreover, submarines were required to undertake patrols in all weathers
and had maintained their positions on station even in the worst winter months when gales, especially in the Heligoland Bight, were so severe as
90. Admiralty, Sept. 1916, ADP 137/2072, 'Review of the Submarine Service'. - 52 -
to require the submarines on many occasions to operate in a shut-down condition for long periods. This made the navigational difficulties among the minefields even greater; the rapidly changing densities of the water in those areas made the trimming and depth-keeping control of the submarine very complex. Recognition of these problems was clearly overdue for a service whose losses in boats were as high as a third.
Developments in submarine construction throughout the War had resulted in an overall increase in submarine size. All new designs had increased endurance but the basic problem in underwater performance remained that of lack of motive power; the submarine could only achieve marginal improvements in this area until an alternative to the storage battery was discovered. Existing systems took up so much space that a reduction in surface speed was necessary to achieve major gains in under- water speed - as in the case of the 'R' class. Therefore, British subma- rine design was concentrated on achieving increased surface speed but even here there were limitations in the development potential of existing diesel engines. The solution to the problem of obtaining greater under- water speed was theoretically seen as demanding the development of an engine which could operate without having to draw in air for consumption.
However such technology did not exist in 1918 and what was needed in order to create a 'true' submarine was a means of propulsion which could be
both operated on the surface and submerged. The time that a submarine could stay submerged was limited by the air supply contained on diving and this, allied to the inefficiency of the electric battery cell system, restricted the submarine's underwater operations to penetration of'enemy waters, evasion of AIS forces, and the final stages of a torpedo attack.
Further restriction of underwater operations was caused by the dependence on the diesel engines for recharging the batteries, an operation which could only be carried out on the surface. Despite the problems with - 55 -
propulsion, submarine designers had learnta great deal in a short period,
especially about the effects of pressures on hulls and in relation to
speed and surface and underwater environments. Thus, the longer the
submarine the thicker proportionately had to be its plating so"as to
resist the same depth pressure as a smaller boat: too much structural
strengthening and the submarine would have very little buoyancy: a"hull
designed for surface speed was not the best shape for deep-diving ability.
Overall then, by 1918, designers were concerned to find solutions to these
twin-problems of propulsion and hull construction.
Clearly the period following the close of the First World War would
have to be a time of evaluation for the existing and potential submarine
types. On the 11 November 1918, the Royal Navy possessed 86 overseas
patrol, fourteen fleet, twenty coastal, six minelaying, one monitor and
six AIS submarines. This was in contrast to the 42 coastal and. 21 overseas
patrol submarines with which the Service had entered the War. There were
many who felt that the-submarine could perform similar roles to some
categories of surface warship and therefore, since it possessed the ability
to submerge, would ultimately replace the latter. However, although the
submarine could add the power of invisibility to a surface warship's
capabilities, it did so only at great cost and could perform the roles less
effectively. Nevertheless, this was a weapon which, although it had not
destroyed a modern capital ship, had severely restricted surface warship
movements and influenced the decisions of Fleet commanders to a degree out
of all proportion to its true threat. The rise of the submarine to military
prominence caused great concern about the future of the capital ship as
the mainstay of the navies of the major Powers. In addition, the success
of the U-boat campaigns in 1917-18 posed problems for the Submarine Service
on the return of peace and this was seen in the reluctance of both Govern-
ment and Admiralty to continue development of the weapon which so clearly
posed a threat to British maritime interests. - 54. -
The bulk of the submarine force had been and continued to be based
on the patrol model. However, the pressures of war and the need to fulfil new roles had resulted in the development of several specialised designs.
The pressures of war meant that resources were more readily made avail-
able and ideas and designs flourished within this materiel luxury. Largely freed from the detailed financial pressures of Governmental and Parlia- mentary control the Admiralty, in common with the other Services, were
able to listen to, consider, and develop a variety of designs as solutions
to individual operational requirements. Submarine development in the
inter-war years was to be- carried out against a background of diminishing 91 rather than expanding naval budgets and in an international environment where attempts to reach agreement on arms limitation were one of the most
persistent threads in British foreign policy. The era of peace opened with the specialist submarines languishing, for the most part, in a limbo
of development but despite the pressure of austerity, presaging the domin-
ance of the general-purpose patrol model, some of these designs were to
survive and continue in development well into the inter-war period.
91. See Appendix: C. - 55 -
SECTION A
DEVELOPMENT -56-
CHAPTER 2.
PATROL SUBr.4ARfl'TE
The Submarine Service and its Component Parts
Despite the success gained by submarines, both British and German during 1914-18, the Royal Navy held firm to its traditional belief in the capital ship as the final arbiter of naval combat, 'In our opinion the capital ship remains the unit on which sea power is built up. '1 However,
British Government policy, influenced by financial and political factors, favoured the disposal of much of the burden of armaments. This coincided with the fact that with the surrender of the German U-boats, the Royal
Navy possessed the largest submarine fleet with a five year development lead over all other navies. Nevertheless, the Government was reluctant to develop a weapon which had demonstrated that it was a grave threat to
Britain's wartime survival. This led to the belief that achievement of an international agreement on abolition of the submarine outweighed any advantage that could be gained by British development of this weapon. In the immediate post-war years pressure for this policy was so strong that the submarine came close to extinction in the Royal Navy. Gradual recog- nition of the impracticality of securing international acceptance for
led this policy towards more limited proposals to constrain the power of the submarine and the inevitably led to a reluctance to spend very much
the money on submarine arm: no more indeed than was, by some standard of
judgement, necessary both to keep in touch technologically and to provide
training to the the anti-submarine rest of Fleet, and to have a force that - in modern parlance could serve as a 'bargaining chip'. The result was
1. First Lord of the Admiralty, W. H. Long, 17 Mar. 1920, ADM 116/1617, 'Statement on the Navy Estimates, 1920-21'. - 57 -
that the British submarine force had to fight initially for its survival and later for sufficient numbers of submarines to enable it to make a viable contribution to British naval strategy.
For political as well as economic reasons, the total of 158 submarines2 vri. th which the Royal Navy had ended the War was to be reduced to only 33 by 1924. The first boats to be scrapped consisted of submarines prior to the 'E' classy and these were to be followed quickly by the bulk of the 4 First world. War construction. In addition, new construction in both private and naval dockyards was terminated and existing installations run down, in the interests of economy. Government policy on the submarine provided the Admiralty with the problem of attempting to maintain some continuity of construction with limited resources, while pursuing the official policy of seeking agreement on abolition, beginning with the
Versailles Peace Conference of 1919. The initial decision was that:
'In the meantime,... until a decision is reached by the Peace Congress as regards the question of prohibiting the future construction of Submarines, no expense should be incurred in connection with the Submarines now in commission or their Parent ships and Depots beyond rrhat is necessary to meet the barest requirements for maintenance of sea-going and fighting efficiency. '5
2. Submarine Archives, H d. S. .? Dolphin - No. of S/lds in the Royal Navy Nov. 1918 May 1920 138 51
Submarine Archives, H. M. S. Dolphin - Scrapping Programme 1919 'A' class (10); 'B' class (9); 'C' class (27); 'D' class; (5).
4. Submarine Archives, H. M. S. Dolphin - -Scrapping Pro amore 1920-24 'E' class (29); 'F' class (3); 'G' class (14); 'w' class (4); 'H' class (20); 'K' class (12); 'J' class (6).
5. Board Minute No. 712,27 Mar. 1919, ADM 167/56. - 58 -
However, this balancing act could not be continued indefinitely and once it became clear that no progress was likely on the abolition issue at
Versailles, then a definite decision for or against development was necessary:
'D. C. N. S. drew the attention of the Board to 1Jinute 712 and pointed out that its provisions were seriously hampering the development of the Submarine Service. The Board agreed that in as much as the Peace Congress had reached no decision on the question of prohibiting the future construction of submarines except as regards Enemy states, the second paragraph of Minute 712 should be rescinded. r6
The policies of retrenchment and economic stringency ensured that this decision did not result in any increase of resources to the Submarine
Service; other"categories of warship were considered to have higher priority and this situation was confirmed the following year:
'Construction of Submarines will not require to be undertaken during 1921-22. Important develop- ments in regard to the internal combustion engine and other factors may be expected during the course of the next year, and prior to full consideration of these developments, it would be unitise to embark on a programme of Submarine replacement and construction. '?
This chapter, and the following four chapters, trace out how the technical possibilities and opportunities for maintaining a reasonably up to date Submarine Service were decided. A good deal of the discussion
centred upon the development of particular types of submarines which could be applied to specialist functions; this method derived in part from the
spread of materiel in the existing inventory, but in part it came from a
6. Board Minute, No. 868,10 May 1919, ADM 167/56.
7. Board Minute No. 1268,13 Oct. 1920, ADM 167/56) See also its appendix - Statement of First Sea Lord, Admiral Beatty. - 59 -
continuing uncertainty about what, in the Royal Navy context, submarines were actually needed to do. Although therefore the specific issues about individual roles and designs were important - this was how the demands of the submarine for money and men could be itemised - the more general debate, about how the submarine fitted into naval planning as a erhole,
planning and, on occasions, how naval fitted into Government policy, also continued throughout the whole of the inter-war period; and this is dealt vrith, in the separate account of policy issues contained in chapters seven to twelve.
The Patrol Submarine
The Royal Navy found itself facing the hard times of peace with a
surfeit of different types of submarine. The increase of roles allocated to the British submarine force during the First World War had led to the development of different models and. designs. The result was that in
November 1918 there were five distinct models in service, comprising patrol, fleet, minelayer, monitor and A/S submarines. The latter two models viere quickly considered to be no longer essential and although in
1939-examples of the other types remained in service, only the patrol model was to be under continuing development. The overseas patrol subma- rine had been the most numerous type constructed during 1914-18. These boats had been used in the greatest varic-ty of roles and in an era of
limited numbers it was logical that this type of submarine, in the form
of the 'L' and 'L. 50' classes should form the mainstay of the British 8 submarine force during the immediate post-viar years.
8. Submarine Archives, H. M. S. Dolphin - Submarine Dispositions 1920 S IA Flotilla Station No. of S/Ms Class 5 Atlantic Fleet- 12 'H. 21' 7 'L. 50' 05 ILI 4 12 'L' 58 ILI - 60 -
failure the Washington Naval Conference9 (1922)_to . Folloiving-the at persuade the French and Italians to accept abolition, the Government was left with no choice'but to concentrate on seeking agreements merely on limitation of the submarine. The continued possession of the submarine by the other major Powers resurrected the Admiralty's need to maintain
Britain's lead-in development. However;. the steadily decreasing tonnage
available to the Royal Navy for submarine construction resulted in an
increasingly limited number of-submarines being deployed to cover many
operational requirements. Clearly there. could. be no possibility of
extensive progress in producing improvements to all existing types of
it that, submarine. -However, was generally-accepted 'Overseas Patrol 10 submarines can do most things and are of general utility. ' The result
was that within weeks of the end of the Washington Conference authoris-
ation was given for design work on a new patrol submarine. In particular
the patrol model was felt to be important for reconnaissance and anti-
warship duties, which constituted the major tactical roles allocated to
British submarines in the inter-war period. Development work on the new
design progressed steadily apart from minor problems on torpedo armament.
D. T. M. was, 'strongly of the opinion that the severe congestion of the
torpedo tube equipment in existing and completing submarines should not
be perpetuated, '11 and the inclusion of two 21 inch stern tubes was
proposed. Although the official opportunity was taken to refute any
9. See Chapter 7.
10. D. of P. to Admiralty, April1922, ADM 158/676% S. 0470/22, National Maritime Museum (N. M. M. ), 'Agenda for 2 May 1922 Conference on Future, Submarine Requirements.,
11. Rear-Admiral (S), H. F. P. Sinclair to Admiralty, 5 Dec. 1922, ADM 138/676,. 1045/S. 011, G. 18269/22, N. M. M., 'New Oversea Patrol Submarine: Request Provision for Two Stern Torpedo Tubes. ' - 61 -
suggestion of overcrowding of bow torpedo armament in earlier designs, 12 no objection was raised to the proposed alterations.
Final designs for the new submarine were submitted to the Board for. approval on 15 February 1925 supported by the proposal that at least one boat should be laid down immediately:
'It was pointed out that the design of the "L" class Oversea Patrol submarine is seven years old and, as this is unsuitable for operating in large areas, it is necessary to have a standard design of proved suitability in order that suitable vessels may be rapidly produced in an emergency. ' In addition: 'It was explained to the Board that if a commencement was made in 1925/24 the Dockyard Staff at present employed on Submarine "X. l" could, when that vessel is finished, be at once employed on the new Submarine instead of being dispersed. tiS
In a political sense, this was a powerful factor to introduce, due to the heavy unemployment then prevalent in the country generally and in ship- building in particular. However, continuing cutbacks in overall naval
construction ensured that the problem of retaining skilled workmen in a
period of financial retrenchment and disarmament was one which remained
with the Admiralty throughout the inter-war period. 14 The original specifications of 10.1 called for a submarine of
250 feet in length and a surface displacement of 1200-1300 tons. However,
the final design included improved wireless transmission (W/T) equipment,
considered necessary for the long range reconnaissance role, and Asdic
equipment, fitted in a submarine for the first time. The result of these
12. D. N. C. to Admiralty, 30 Dec. 1922, ADM 138/676, N. 1d.M.., 'Views on R. A. (S)'s Memo,.
13. Sinclair to Admiralty, 15 Feb. 1923, ADM 167/67, 'Board Minute No. 15861.
14. See Appendix: D(24). - 62 -
alterations was an increase in length of 25 feet and a rise of surface 15 displacement to 1490 tons. 'In addition increased accommodation for the officers and men had been provided as compared with previous submarines 16 to allow for operation in tropical waters., This was a reflection of the growing concern over Japanese naval strength following the decision not to renew the Anglo-Japanese Alliance. '0.1' was approximately 40 feet longer and four feet wider in the beam than the 'L' class but 2 knots slower. However, the latter factor was compensated for with a greatly increased fuel capacity and larger torpedo armament, which allowed a longer period on patrol than any previous British submarine. The bonus of increased fuel capacity was marred by a fault in the storage system.
Fuel was stored in the external ballast tanks since it could only have been carried within the pressure hull by enlarging the dimensions of the submarine even further, which was considered undesirable. After invest- igation the conclusion was that any increase in size could be kept to a minimum by utilising the upper half of the ballast tanks. These were less strongly constructed than the pressure hull since they filled with sea water as the submarine submerged and were not subjected to the unequal pressure which provided the main danger to the pressure hull. The fuel. intake valve to the diesel engines was positioned on the top of the ballast tank and as the fuel was used it was replaced by sea water entering from below and keeping the tanks full. The fact that the less dense fuel oil floated on top of the water prevented any salt water from entering the engines. In addition, no air space was left to provide unwelcome buoyancy
15. Admiralty, 15 Feb. 1925, ADM 1/9251, 'Legend and Design of Submarine "0.1". '
16. D. N. C. to Admiralty, 25 Oct. 1925, ADPA1/9245, 'New Oversea Patrol Submarine. ' - 65
on the surface or to cause the tanks to crumple under pressure when
submerged. However, leakage was quite prevalent due to the light plating
and this meant that '0''and later 'P' and 'R' class submarines had a
constant problem when submerged to prevent leaking oil leaving a clear trail-on the-surface, marking the submarine's position. Much of the
experience on the operation of submarines,. during the First World War, was put into the design of 10.1' and this included the construction of a
stronger pressure hull giving a good deep-diving ability and the sub-
division of the ballast tanks to provide a quicker initial diving time.
Meanwhile, problems continued to arise over the gun armament to be
fitted. Existing designs included provision for only one 4 inch gun plus
an anti-aircraft (A/A) armament of machine guns. Rear-Admiral (S)
considered it-possible, 'without detracting to any appreciable degree
from the primary functions of the vessel, to fit a heavier gun armament, '17
and his proposal was to fit-either a twin 4 inch or a single 5.2 inch gun.
Expert opinion delivered to the First Sea Lord was that of the al. tern-
atives, proposed the 5.2 inch was preferred. - This was largely because a
twin 5.2 inch mounting already existed and production of a single gun 18 version of this design was expected to provide few problems. Neverthe-
less, for a variety of reasons the final'decision favoured retaining the
4 inch gun. One factor was that the substitution of a 5.2 inch would
double the weight of the gun mounting and revolving platform. Moreover,
the magazine space could not be increased which meant a reduction in the
the number of shells if larger calibre was fitted. A larger gun was also
17. Nicholson to Admiralty, 10 Max. 1924, ADLE138/676., 276/S. 110,, in G. 0210/24, N. M. M.
(J. 18. D. N. O. w. Henley) to Beatty and Third'Sea Lord, 19 Mar. 1924, ADM 138/676, N. M. M. - 64 -
expected to have "an adverse effect on the operational capability of the 19 submarine. Finally, the deciding factor was the number and placing of the torpedo tubes, which were the primary armament requirement.
The results of sea trials and operational experience with '0.1', renamed 'Oberon', led to the decision to include an improved design in the 20 1926 Estimates. These six '0' class (Odin class) submarines were foll- owed by orders for a further six patrol submarines of the 'P' (Parthian class)21 in the 1927 Estimates. The 'P' class boats were similar in design to the 'Odin' class but differed in having a slightly larger engine room.
Surface and submerged speeds and armament were intended to be similar to 25 the previous class22 and this resulted in early approval by the Board.
As with 'Oberon' there was an extensive discussion on the relative merits of increasing the gun calibre but this time only to 4.7 inches, which was already a standard fitting on destroyers and could lead to economies of production and supply. One aspect of this debate reflected current
official thinking on patrol submarine gun armament. The power of conceal- ment by submergence was reaffirmed as being the submarine's prime asset
and if the pressure hull was holed then the submarine would be unable to
submerge. Therefore it was expected that:
'Gun action will ... only be forced on a Submarine through surprise or damage. Normally she can choose whether to engage on the surface or submerged and All only select the former when the enemy is of inferior gunpower. The urgency of the duty on which he is employed may,
19. D. N. C. to Admiralty, Apr. 1924, ADM 158/676., NX. M. . 20. See Appendix: D(25).
21. See Appendix: D(26).
22. D. N. C. to Admiralty, 28 Sept. 1927, ADM 1/9278) '1927 "0" Class Submarine'.
25. Board Minute No. 2369,7 Oct. 1927, ADM 1/9278p 'Approval of Legend and Drawings 1927 "0" Class Submarine'. - 65 -
'however, decide the Submarine Commander to remain on the surface at all costs, and the greater his gunpower, the greater his chance 24 of engaging on equal terms. '
This opinion partly explains R. A. (S)'s preference, during design discus- sions on '0.1', for a 5.2 inch or twin 4 inch rather than a single 4 inch gun. Supporters of both heavy and light armament looked for support in the types of target which a patrol submarine was considered likely to have to engage. These included all types of surface craft, including troop- ships and storeships, other submarines, aircraft, and, on occasions, shore targets. On the surface, although presenting a small target, a submarine was considered to be slow to manoeuvre and therefore was seen as running the danger of being sunk by ramming, so a long-range-. gun action was to be preferred as the least of the evils. Against air attack the combination of machine guns and a4 inch H. A. was preferred to the 4.7 inch gun which, although capable of greater range, could not be elevated sufficiently. The advent of longer range maritime aircraft led to an increase in A/A armament, principally in the form of heavy machine guns.
However, in the event of either surface or air attack the natural response of a submarine was still seen as submergence and evasion. This, allied to the problem caused by increased displacement on speed and endurance, tended to influence any decision so as to rule initially against the heavier calibre gun. However, prior to building it was decided to include a
4.7 inch gun in the design of the 'R' ('Rainbow') Class, which were laid down in 1929.25 These were similar to the 'Parthian' class which had
24. D. of G. D. to D. Of P., 3' Aug. 1928, ADM 1,38/6763 G. D. 2647/28, N. M. M., 'New "P" Class Submarines - Relative Advantages and Disadvantages of Arming with (a) 4 inch H. A. or (b) 4.7 inch L. A. Gun. '
25. D. N. C. to Admiralty, Sept. 1928, ADM 1/9294, (Board approval. granted in Minute No. 2508). See Appendix: D(27). - 66 -
undergone minor design changes, including modification of the bow shape, resulting in a six feet increase in overall length. This and the increase in oil fuel storage caused by using the external tanks for emergency fuel instead of being forced to use a tank in the pressure hull (a policy reversed in 1932) led to an increase in displacement of approximately 26 50 tons. The overall similarity of design of these three classes reflected adherence to the concept, which existed in the late 1920's, of the 'general-purpose' submarine which was defined as a boat, 'in which 27 no requirement is unduly stressed at the expense of another., In
addition, the restriction on numbers of new submarines laid emphasis on keeping to similarity of designs in order to facilitate training, the provision of spares and other factors such as overhaiUs. But support was
given to the policy of building a new type of small patrol submarine (the
'S' type) to replace the ageing 'H' and 'L' classes. Both the Submarine
Service, in the person of R. A. (S), and the Naval Staff favoured building
a number of these submarines for shallow-water work, training, and defence 28 of Far Eastern bases.
Requests were also sent out to the C. in C. 's of the Atlantic and
Mediterranean Fleets for their views on future submarine requirements,
including whether all patrol submarines should have an operational speed
of 18-19 knots. The principal arguments in favour of this development
were that increased speed would facilitate the ability of patrol subma-
rines to shadow enemy forces, whether transports or warships. Arguments
against centred on the belief that 19 knots was insufficient for the
26. D. N. C. to Controller, 2 Oct. 1928, ADM 1/9288,5.0.6243 28.
27. E. in C. to Admiralty, 16 Dec. 1926, ADM 116/2522.
28. Admiralty, 9 July 1928, ADM 116/2522, 'Decisions by Sea Lords on Future Submarine Policy. ' - 67 -
purposes of shadowing an enemy fleet and unnecessary for shadowing trans- ports. The C. in C. 's were informed of the, 'strong body of opinion-in
favour of allocating a proportion of our total. Submarine building programme
to the construction of small submarines, of the nature of approximately 29 600 tons surface displacement. ' The Admiralty were clearly anxious to
obtain as much operational opinion as possible before deciding. I.
The attitude to future patrol submarine development, within one
section of the Submarine Service at least, was demonstrated by the stated belief that overseas patrol submarines should be capable of high oceanic
endurance and a good surface speed of 18-19 knots. In order to achieve
the latter, sacrifices in other qualities, such as armament and diving
depth, -could be accepted but if this proved impossible;
'then the increased size and cost involved in building vessels of the "G" type design is held to be fully justified. Further, if financial restrictions do not permit of the full projected number of "Oversea Patrol" submarines being of the - "G" type, then it is considered far preferable to accept a lesser number of the "G" te rather than a greater number of the "0" type. 13Y
The opinion of both C. in C. 's was that the 'G' class design could be used
to produce a submarine to fulfil both Fleet and Overseas patrol duties
since the former role no longer included the need to take part in a fleet
action and therefore a speed in. excess of the battlefleet's top speed was
no longer required. They held that future submarine. programmes should be
concentrated on the 'G' class and a small patrol type for coastal and
29. Admiralty to C. in C. 's Atlantic and Mediterranean Fleets, 21 Aug. 1928, ADM 116/2522,11.0.2512/28.
30. Captain (S), 1st S/M Flotilla, to C. in C. Mediterranean Fleet, 26 Nov. 1928, ADM 116/2522,016. (Enclosure No. 6 to Mediterranean Letter No. 2331/084/11.37 of 23 Dec. 1928). - 68 -
training duties. Strangely, the C. in C. Mediterranean Fleet, Admiral 31 Field, was more concerned with future overseas submarine requirements32 while his counterpart with the Atlantic Fleet, Admiral Brand, devoted 35 much of his reply to the coastal type. This was the reverse of what might logically be expected since the Mediterranean was unsuitable for large submarines, because of shallow coastal water and short distances to patrol areas, such as the Italy-Libya route. In addition, the develop- ment of maritime aircraft for use in the A/S role meant that in clear stater areas such as the Mediterranean, a submarine could be spotted 80 to
90 feet below the surface. The Atlantic required the larger submarine mainly because of endurance requirements. However, in the sense of requiring 'fleet' submarines both would have similar requirements. On the question of small patrol submarines, Admiral Field restricted himself to one short paragraph and expressed the desire for such submarines to be
capable of laying mines; this ignored the research and development work, underway for over six years, to produce a specially designed minelaying
submarine. Admiral Brand, however, considered the small patrol type to be important enough a requirement to justify as much space in his report
31. Field, Sir Frederick Lawrence (1871-1945), Admiral of the Fleet; b. 19 Apr. 1871; D. T. 1,I., June 1918 - Mar. 1920; Rear-Admiral, Feb. 1919; Third Sea Lord and Controller, 15 Apr. 1920 - 15 May 1923; C. in C. Battle Cruiser Squadron, 1923-24; D. C. N. S., 15 May 1925 -1 May 1928; C. in C. Mediterranean Fleet, 8 June 1928 - 26 May 1930; Admiral, April 1928; First Sea Lord and C. N. S., 50 July 1950 - 21 Jan. 1935; Admiral of the Fleet, 1953; d. 24 Oct. 1945.
52. Field to Admiralty, 23 Dec. 1928, ADIvT116/2522, 2331/084/107, 'Submarines - War Requirements and Characteristics. '
33. Brand to Admiralty, 23 Nov. 1928, ADMM116/2522, 2181/A. F. 003, 'Design of Submarines., - 69 -
as the 'G' class. Among the advantages of the smaller submarine, that of rapid production was seen as extremely important. A larger boat, of 700 rather than 600 tons would allow a longer endurance and" a better sea-speed.
Gun armament was not considered essential but the precaution of including
'structural arrangements' to fit a deck gun, if required, was advocated.
Finally, a possible speed of 14 knots (surface) and endurance of 5,000 miles at 10 knots was seen as allowing these boats even to be used in the rar
East. The latter condition clearly verged on the optimistic but obviously the greater the degree of support which could be given in the way of over-
seas patrol duties the easier would be the transition from peacetime to war conditions.
Consideration of these replies by the Admiralty (Controller, Deputy
and Assistant Chiefs of the Naval Staff), led to a decision to hold a
further meeting for the 25 April to consider proposals on both types of
submarine. Prior to this Plans Division circulated a memorandum on prop-
osed submarine-building programmes, including provision for the 'S' type
small patrol submarine. The Staff Meeting of 18 June 1928 had recom-
mended that twelve IS' type boats be built and these later-proposals
essentially confirmed this view, allied to detailed annual programmes,
specifically six submarines in 1929-31 and six more during 1933-35. Only
two 'S' type per year were to be laid down, 'in order to speed the building
to the for ('G' evenly ... and suit programme the larger submarines. '34
type). However, initially the later six boats were to be regarded as 35 only provisional. _
34. Plans Division, 22 Mar. 1928, ADM 116/2522, P. D. 05254/29,1-2.
35. See Appendix: E(2). -70-
36 '-S' Class
The requirement for a small patrol submarine stemmed from two main factors. These were the need to replace the 'L' and 'H' class submarines
in the training role and the inability of the larger submarines, ' whether
'0' or 'G' class, to operate efficiently in shallow restricted waters.
Under the definition of standard tonnage, agreed to at the 1927 Geneva
Tripartite Naval Conference, the'tonnage of the 'L' class was fixed at
760 tons and the 'H' class at 410 tons. £Lthough in 1928/29 it was
intended, hopefully, to be able to replace both classes with one new
design, the need to use the 'S' class entirely for patrol duties during
the 1930's led to the design of a still smaller submarine primarily for 37 the training role - the 'U' class.
Initial design requirements for the IS, type included an armament of
six bow torpedo tubes and, 'Sufficient oil fuel to give the vessel the
endurance to proceed to a patrol position 500 miles from base, remain on 58 patrol ten days and return 500 miles to base. ' This distance was cons-
idered. to be the maximum possible without increasing the size and there-
fore the weight of the W/T installation. A design based on these
requirements was calculated as needing to be at least 600 tons. Habitability
and sea keeping endurance, based on the operational use of the 'H' class,
which had been restricted to 5/6 day patrols during the First World War,
also indicated a tonnage over 600 tons, with the preference being indic-
ated at approximately 760 tons.
36. See Appendix: D(30).
57. See Appendix: D(32).
38. Rear-Admiral (S), H. E. Grace to Admiralty, 16 Feb. 1929, ADM 138/720,153/S. 0.22,1.1.0470/29,1-2, N. M. M. - 71 -
In certain quarters, submarines of the size and displacement of the
10' class were considered unsuitable for operations in confined waters.
Whereas the proposed new design would-only require approximately 50 feet to submerge its periscope standards, the larger patrol boats required
43 feet, which although 'E' class submarines had been used in the Baltic during 1915-17 meant that:
?the operation would be attended by considerable risk dependent on the anti-submarine measures of the enemy; and when on patrol it is certain that the large submarine would not be able to maintain such a close patrol as the smaller vessel, both for reasons of visibility when on the surface at night and because she would require more water for diving. ' 9
Admiralty comment on these proposed requirements remained unenthusiastic: it being considered, 'doubtful whether it will be possible to incorporate
(S) all the requirements asked for by R. A. and the Naval Staff on 40 600 tons. ' The Admiralty also strongly disagreed with R. A. (S)'s requirement for a patrol range of 500 miles since this depended for feas-
ibility on the availability of a base in the Baltic. The political
situation in the various countries bordering this Sea was such as to
give no guarantee that a base would be available. Therefore, it had to be concluded that; 'These submarines must be capable of working from a base some 1200 to 1300 miles distant, and, if the length of time on
patrol is taken as eight days, this will necessitate twenty at sea at 41 a stretch. ' On the evidence and opinions collected the list of design
requirements included a displacement of 600-700 tons (standard) but it
39. Ibid.
40. D. of T. D. to D. N. C., 22 Feb. 1929, ADM 138720, i s. 0470/29,3, N. M. M.
41. D. of P. to D. of T. D., 12 Mar. 1929, ADM 138/720, 14.0470/29,4-5, N. M. M. - 72 -
was admitted that; 'The figure of 600 tons has been chosen partly for 42 political reasons. ' Speed on passage was to be 9 knots, giving a radius
of 4,500 miles plus eight days on patrol. Armament was six-21 inch bow
torpedo tubes and if a larger design was accepted then two extra stern
tubes were preferred over increased speed. Finally, a diving depth of
300 feet was specified because, 'the small submarine is likely to be much hunted in narrow waters and, must have a robust pressure hull to resist ' depth charge attacks.
In line with D. of T. D. 's suggestion, Vice-Admiral Pound. (A. C. Pr. S. ) proposed that it would probably expedite a decision if, two sketch designs 45 were prepared. The Controller, Admiral Backhouse46 then forwarded these 46 designs47 to the Naval Staff Meeting scheduled for 25 April. Rear-Admiral(S)
42. D. of T. D. to A. C. N. S., 19 Mar. 1929, ADM 158/720, 14.0470/29,5-7, N. M. M.
43. Ibid.
44. Pound, Sir (Alfred) Dudley (Pickman Rogers) (1877-194, x), Admiral of the Fleet; b. 29 Aug. 1877; D. of P., 1917; D. O. D., 1917-20; D. of P., 1922-25; A. C. N. S., 1927-29; C. in C. 'BB. C. Squadron, 1929-52; Second Sea Lord, 31 Aug. 1932 - 50 Sept. 1935; C. in C. Mediterranean Fleet, 20 Mar. 1936 June 1939; First -5 Sea Lord, 15 June 1939 - 15 Oct. 1943; d. 21 Oct. 1943.
45. Pound to Controller, 20 haar. 1929, ADDM158/7202 1.0470/29, N. M. M.
46. Backhouse, Sir Roger Roland Charles (1878-1939); Admiral of the Fleet; b. 24 Nov. 1878; D. N. O., Sept. 1920-Dec. 1922; C. in C. 3rd B. S. Atlantic Fleet, May 1926 - May 1927; Third Sea Lord and Controller, 1 Nov. 1928 -1 Mar. 1932; Vice Admiral, Oct. 1929; C. in C. Ist B. S. Mediterranean Fleet and Admiral, Feb. 1934; C. in C. Home Fleet, 20 Aug. 1955 11 Apr. 1938; - First Sea Lord, 17 Nov. 1938 - 15 June 1939; ret. June 1939; Admiral of the Fleet, 7 July 1939; d. 15 July 1939.
47. See Appendix: E(3).
48. Backhouse to D. N. C., 20 Mar. 1929, MA 138/720, M. 0470/29, N. M. M. See also: D. N. C. to Backhouse, 15 Apr. 1929, ADM 138/720, M. 0470/29, N. M. M. -73-
still favoured as small a submarine as possible in order to increase the
areas of shallow water in which the new boat could work, and pressed for
further reductions in the 'S. l' design, despite the D. N. C. 's assurance
that weights and buoyancy had been out to the limit in preparing this design.
Nevertheless, Rear Admiral Grace estimated that operational endurance could be cut further and surface speed reduced. to 12 knots. The Admiralty
that, countered 'the power for 14 knots was almost as easy to provide as for 12. '49 Vice-Admiral Pound was adamant that, 'he could not accept
12 knots as surface speed as the vessel would be unable to catch up even 50 relatively slow vessels, ' on which basis agreement was reached in the need for 14 knots. Submerged speed was an easier problem with unanimity almost immediately on the need to increase to 10 knots, and. D. N. C. considered, 'this was an easier problem in a small submarine than in the 51 ('G' large one. ' type). A certain amount of disagreement existed on the question of alternative bow torpedo tube armaments. However, it was
that accepted neither design allowed for stern torpedo tubes, as these involved to a considerable addition the length of the submarine and
increase in displacement necessitated an of 30-40 tons. The issue resolved into whether there was any significant weight saving in armament between the designs but-the D. N. C. this considered unlikely. Therefore the arma- ment question was left open pending revision of the larger design. mean-
the D. N. C. while, remained convinced, 'that all the requirements could not be in the design embodied small and that, if embodied, the upper limit of
760 tons Geneva displacement would be approximately reached. '52 Despite
49. Ibid.
50. ADM 1/9297,25 Apr. 1929, 'Liinutes of Staff Meeting. '
51. Ibid.
52. ADM 1/9297, 'Minutes of Staff Meeting. ' (See Note 50). -74-
this, the decision was to instruct the D. N. C. to prepare another sketch embodying all the requirements for this type of submarine, to ensure that all possibilities had been covered before reaching a final decision.
The new design was finished in just over a month including provision 55 54 for six-21 inch bow tubes. Admiral Madden then concurred in the request55 for a meeting to be held on 6 June56 attended by the Sea Lords and R. A. (S). The Controller considered that the new design was sufficiently satisfactory to contemplate including two boats in the 1929 programme. The
'S. l' design had been taken as the basis for the revised sketch and in addition to the increases'in the torpedo armament, Asdic had been included, as well as increased battery power so as to achieve the 10 knots submerged speed requested. There was general agreement that the design met both the Naval Staff and R. A. (S) 's. requirements and it was forwarded for 57 approval.
Approval meant the acceptance of a small submarine of over 600 tons
standard displacement and signalled the collapse of one of the British limitation arguments advanced at the 1927 Geneva Naval Conference, which
favoured submarines not exceeding 600 tons. Although the theory had been
that small submarines would not possess sufficient endurance to threaten most British trade routes, the 'S' design possessed a radius of 3,000 miles
55. D. N. C. to Backhouse, 27 May 1929, ADM 1/9297.
54. Madden, Sir Charles. Edward (1862-1935), Admiral of the Fleet; b. 5 Sept. 1862; Admiral, Feb. 1919; C. in C. Atlantic Fleet, 8 Apr. 1919 - 14 Aug. 1922; Admiral of 1924; 'First the Fleet, July Sea Lord, 30 July 1927 - 30 July 1930; d. 5 June 1935.
55. Backhouse to Madden, 31 May 1929, ARA 1/9297.
56. ADM 1/9297,6 June 1929, 'Minutes of Sea Lords Meeting.
57. Secretary to Board, 20 June 1929, ADM 1/9297, 'Design for "S" type Submarine. ' - 75 -
on 600 tons which clearly nullified this belief. Nevertheless, the Board granted preliminary approval to the design, noting that the 600 tons limit 58 had not been accepted by other nations, followed by final approval of 59 the definitive 'S' class design. This included provision for the 3 inch
H. A. gun to be fitted on a disappearing mounting, 'so as to reduce resis- 60 tance to submerged propulsion. '
The initial group of four is, class submarines were ordered under the 1929 and 1930 programmes, while later boats were subject to several modifications, which increased standard displacement by 30 tons. The designs for this second group, starting with the 1931 programme, were approved by the Board on 9 May 1932.61 The oil fuel continued to be stowed internally because of past experience with leaking external fuel tanks. However, the 3 inch gun was now mounted on the casing deck, allowing the conning tower to be lowered reducing the silhouette on the surface. The initial four 'S' class later had their gun armament modified to a fixed mounting and pre 'gar production of this class was terminated with the eight boats of the second group, ordered 1931-35. Following the outbreak of the Second World War the 'S' class were put back into prod- uction, the initial five boats of this third group being based on the 1951 designs, and the remainder built from modified designs, including an external stern torpedo tube and heavier A/A armament (20 mm). Half were of partly welded construction and the remainder were wholly welded. The
58. Board Minute No. 2603,27 June 1929, ADM 1/9297) 'Sketch Design of "S" type Submarine. '
59. Board Minute No. 2665,28 Nov. 1929, ADM 1/9297) '1929 Class Submarine: "S" Design. '
60. D. N. C. to Backhouse, 25 Nov. 1929, ADM 1/9297, S. 0.3550/29,1.
61. Board Minute No. 2959,9 May 1932, ADM 167/87, 1 'IS" Class Submarine of the 1931 programme. ' - 76 -
'S' class were to be in production for fifteen years from 1931 and had the unique distinction of being the only class of British submarine to remain in production throughout the vrar period.
'T' Class62
The success of the 'S' class submarine appeared to satisfy the requirement for a boat capable of operating in restricted European waters but a need still existed for a larger submarine with the necessary endurance to carry out patrols over the vast distances of the Indian
Ocean and the Pacific. The restrictions of cost and of tonnage limitation agreements, such as the London Naval Treaty, prevailed against further
('River' construction of the 'G' type class) as patrol submarines and even in the Fleet-co-operation role only three boats were built.
Therefore, a new design was considered necessary to replace the '0' class in the late 1930's. Climatic conditions dictated the need for good habitability, especially for the Far East, and this indicated a requirement for a medium to large patrol submarine. However, once again the effects of tonnage limitation agreements intervened., as the British supported an
American proposal, at the 1932 Geneva Disarmament Conference, setting a qualitative limit for submarines of 1200 tons. Nevertheless, whatever the final decision on displacement, operational requirements dictated an endurance of approximately 9,500 miles, to meet the requirement of a
'distant reconnaissance' capability from Singapore to Japan, as well as
a diving depth of 300 feet. The resulting designs were ready by August
1952 and as well as satisfying the stated requirements it had been decided
to omit the two stern tubes. It was, 'considered that with the present
development in the angling of torpedoes this is not a serious drawback. '65
62. See Appendix: D(31).
63. Rear-Admiral (S), C. J. C. Little to D. C. N. S., Vice-Admiral Frederick C. Dreyer, 18 Aug. 1932, ADM 116/3617. - 77 -
Twelve hundred tons was considered to offer a good basis for compromise on the various qualities of speed, endurance, armament, and diving depth needed on difficult Far'East patrols. However, the fact that speed would be below 20 knots precluded any use with the Fleet.
Before any conclusions could be reached on the designs, the failure of the Geneva Disarmament Conference and the Hoover Proposals led to a further study of requirements which dragged on into 1934. Then prepar- ations for the 1935 London Naval Conference intervened; British policy was to concentrate on seeking agreement ön quantitative tonnage and main- taining the qualitative limit at 2,000 tons. Only 40,000 tons were to be requested for the British submarine force, provided the other Powers agreed to similar reductions in their submarine forces, but it'was recognised that in policy terms,
'this necessitates the abandonment of the "G" type in order to obtain the number of submarines we require on that basis, ' despite the fact that, 'any reduction of the submarine tonnage of the Great Naval powers below the present amount of 52,700 tons is only a pious hope. '64
Therefore, work on the new patrol submarine design was continued although
to now reduced 1,000 tons standard displacement, and the 'H' class subma- rines were to be replaced by a new 400 ton design for use specifically in
A/S training.
Initial sketch designs were completed by April 1934 and included 65 alternative proposals for both the 1,000 tons and 400 tons submarines.
Restriction of standard tonnage to 1,000 tons and an increase in submerged
speed was calculated to result in a design of similar dimensions to 'B'
64. D. C. N. S., Vice-Admiral C. J. C. Little to Controller, Rear-Admiral Charles M. Forbes, 27 Feb. 1934, ADM 1/9573, M. F. O. 2506/54-.
65. See Appendices: E(4) and E(5). - 78 -
but with a surface speed of only 14 knots and an endurance of 8,600 miles at 8 knots or 5,500 miles at 11 knots. On armament, the arrangement of torpedo tubes included six-21 inch bow tubes with four external 21 inch tubes mounted in pairs, one above the other, in an amidships position angled at 100 to the middle line of the submarine. The final decision on the external tubes depended on the progress of a new design then under development. An innovation was the fitting of one-man air locks, to 66 facilitate the use of the Davis Escape Apparatus. The intention was to include one submarine, based on the D. N. C. 's designs, in the 1955 prog- ramme67 but the preparation of a definite legend and drawings was delayed pending the circulation of a memorandum outlining the major requirements 68 and proposals. -The decision to limit the new design to approximately
1,000 tons (standard) was not only tied into British proposals for the
1955 Naval Conference but accepted the practicability of building a satis-
factory patrol submarine on this arbitrary displacement. Once again political decisions were apparently to be allowed to take precedence over
military requirements. However, -since the existing submarines were-of
1,500 tons displacement, clearly every improvement in submarine material
and design which had been made in the earlier boats would have to be used.
Final choice of an eight torpedo salvo was based on the calculation
that this would allow one attack on an important target, with six reloads
for further attacks. Gun armament in submarines had finally been accepted
in principle during 1955 on the basis of the argument that: -'A gun is
66. D. N. C. to Controller, 19 Apr. 1934, ADM 1/95753 M. F. O. 2506/34,1-5.
67. Board Minute No. 3245,25 Oct. 1954, ADM 16790, 'New Construction Programme 1935. '
68. Tactical Division, Nov. 1954, ADM 1/9375, T. D. 128/34, 'Memorandum on 1,000 tons Submarine, ' 1-17. -79--
trequired for self defence if unable to dive, to attack an A,/S vessel 69 which'is holding contact and to attack an enemy submarine on the surface, ' and a3 inch or 4 inch was proposed. In deciding on requirements for endurance the latest information on the 'P' and 'R' classes was consid- 70 ered, resulting in a figure of 6,000 miles at 'operational speed, ' plus
28 days on patrol. Surface speed'was considered important in connection with crew endurance, since the new design was intended primarily for
service in the Far East. The slower the speed naturally meant a'longer time on passage and a-reduced period in the patrol area. Therefore, in tropical waters a fairly high speed was required but, due to the marine
growth fouling problem in the tropics, 11 knots as an operational speed was considered. desirable, giving a time of fifteen days on a passage of
4,000 miles. However, the opinion was that existing diesel engines should not be run above three-fifths power and the existing 15 knot designs were not considered adequate to achieve the 13-14 knots design speed. If this problem could not be rectified then a considerable increase in fuel stowage had to be provided. The requirement for submerged endurance was a maximum
of 5 knots for eight hours and a minimum of fifteen hours at 2 knots. No problem existed with the proposed maximum submerged speed as 9 knots was
considered satisfactory.
increasing The use and efficiency of aircraft, as well as high speed
surface vessels, in the A/S role, meant that the new submarine had to possessa very quick diving capability, in this case 50 seconds from a
8 knots fifteen surface speed of and seconds at 20% buoyancy. Once ",
69. Ibid.
70. AD?S 1/9375, '1,000 tons Submarine. ' (See Note 68). (This term was defined as the speed to be made good in normal weather conditions to carry out the operation required. ) - 80 -
submerged the boat had to be able to dive deep since it was considered that 'the ability to go to the bottom and stop is one of the best means of avoiding detection 'by A8dic. '71 This was taken by operational submarine commanders to indicate a capability to dive to 500 feet, at a time when
R. A. (S)"and others were arguing that 500 feet was a sufficient depth to avoid most enemy A/S forces. A 500 feet depth capability was expected to,
enable the vessel to-bottom in large areas to the West and S. Y.I. of Japan, and also in'the entrance to the Sea of Japan close inshore, '72 and these viere areas where the greatest concentration of A/S forces-were likely to be found, rather than in deeper water. Therefore, providing a 500 feet diving' capability could be provided on the final agreed tonnage, the operational commanders were right to insist on as deep a diving depth as possible. This was important especially to allow for possible develop- ments in the'range at which Asdic could detect submarines.
A recurring problem with the existing patrol submarines of the '0',
'p' and 'R''classes concerned leakage of oil fuel from external tanks.
Therefore the proposal was to store all oil fuel within the pressure hull.
Meanwhile, numerous suggestions were forwarded to enable the submarine to avoid being sighted first on the surface, such as a small bridge structure and reduction in length of periscope standards. This was apparently cons- idered' so important'-that it was' even proposed that the shape of the hull be altered to allow a long periscope to be lowered further. Modifications
smoke were also to be made to the exhausts of-the main engines and to the main tanks vents, to prevent them throwing up columns of spray when diving.
71. ADM 1/9875, 11,000 tons Submarine. ' (See Note 68). Stc. atj, ýPZ05-20(
72. ADM 1/9573, '1,000 tons Submarine. ' (See Note 68). - 81 -
Nevertheless, both the 'A' and 'B' designs were regarded as unsatis- factory in endurance, speed, submerged manoeuvrability and habitability.
Among the various suggestions put forward for reducing displacement was the omission of escape facilities as these were considered a limitation on operational efficiency in war. Other proposed improvements to the designs largely centred on increasing endurance. Although agreeing that:
'Strategically, the bigger the endurance the better,? nevertheless, 'in practice patrols at very long distances are open to various objections. '75
These included unreliability of communications, limited value of long distance intelligence, long and uneconomical passage time, difficult passage back to base if damaged, and time required to replace a submarine out of action. Ignoring the tactical requirement to operate the new submarines from Singapore on patrols off Japan, D. of P. favoured restr- icting patrol requirements to 1,500 miles and a total endurance of 5,000 miles. However, as he admitted, this assumed the availability of a for- ward base and Hong Kong, the only one available, was highly vulnerable.
However, while agreeing that 28 days was the maximum patrol that could be
(S) expected of personnel, R. A. considered that on certain operations the 74 new design should be able to remain at sea for 42 days.
The fitting of external tubes amidships was expected to allow the
inclusion of a broad upper deck, with space for crew exercise. Trials of
a submarine built by Vickers for the Portuguese Navy had shorn that such 75 a deck did not adversely affect submerged control. It was realised that
a quick decision was needed if the first boat was to be included in the
73. D. of P. to D. of T. D., D. W. Boyd, 22 Jan. 1955, ADM 1/9373, M. F. O. 2506/54,4.
74. Rear-Admiral (S), C. P. Talbot to Boyd, 15 Mar. 1935, ADM 1/9373,010, M. F. O. 250634.
75. D. N. E. to Talbot, 2 Feb. 1935, ADM 1/9373, M. F. O. 250634,5. - 82 -
1955 Estimates. Based on these recommendations a third design was under- taken by the D. N. C. which resulted in a submarine of 1,075 tons (standard).
The main modifications concerned surface endurance, now 5,000 miles at
11 knots. Storing all the oil fuel required inside the hull resulted in dimensions similar to the '0', 'P' and 'R' classes. Calculations indic- ated that to achieve a displacement of 1,000 tons (standard) would 76 necessitate a reduction in length of 13 feet and in endurance of 600 miles.
This design was then considered by a Naval Staff conference, whose recom- mendations included a compromise on escape arrangements, with an Italian
) type air-lock (favoured by D. of T. D. being fitted forward and the British type (favoured by D. N. C. and R. A. (S)) fitted aft. Overall length was reduced :50 feet, 'by placing a certain amount of the fuel in a pressure tight tank exterior to the normal line of the pressure hull. '77 However, by following these recommendations, the military requirements could not 78 be incorporated, ' and the result was a modified design of 1,095 tons, with the length reduced by fifteen feet, which was accepted on 15 May 1935.
However, further departmental discussions proved necessary before 79 the revised design was placed before the Board for approval. The problem , of leaking fuel oil was to be solved by storing all 155 tons of
oil fuel inside the pressure hull, while the decision to fit four external boor torpedo tubes resulted in the most powerful armament in post-war
76. D. N. C. to Controller, Vice-Admiral Reginald G. H. Henderson, 23 Apr. 1935, ADM 1/9378, M. F. O. 598/55,1.
77. Admiralty, 1 May 1955, ADM 1/9378, M. F. O. 598/55, 'Minutes of Conference, ' 2. (Attended by Controller, A. C. N. S., R. A. (S), D. N. C., D. E. in C., D. E. E., D. N. E., D. of T. D. ).
78. D. N. C. to Henderson, 26 June 1935, ADM 1/9378, M. F. O. 398/35.
79. Board Minute No. 3505,1 Aug. 1935, ADM 167/92, 'Sketch Design of the Patrol Submarine ("T" class) of the 1935 Programme. ' - 85 -
British submarines. This arrangement to allow larger salvoes of ten
torpedoes submerged and eight torpedoes surfaced, was considered necess-
ary because of the increasing size of warships and the belief that modern
capital ships were capable of absorbing several hits. Reloads could only
be carried for the six internal tubes and therefore there was no increase
in the total number of torpedoes. After 1939 all 'T' class submarines
were fitted with an external torpedo tube aft and the external beam tubes
were realigned also to point aft. The bridge casing was extended forward
in all these boats to enclose the 4 inch gun mounting and breastwork.
Following the 'Triton' further 'T' class submarines were ordered under
the 1936-39 Estimates. In order to evaluate new diesel engine design,
the boats of the first group were fitted with different engines depending 80 on where they were built. The outbreak of war halted these tests and
new 'T' class construction was equipped with either Vickers or Admiralty
diesel engines. A further 47 boats of the 'T' class were ordered under
the 1939 Supplementary Estimates and 1940-42 Emergency War Programmes.
Then construction of this type concentrated on the 'A' class, which were
timproved' 'T' class boats. Sixteen 'T' class were war losses and seven f-eov-A (four cal were cancelled being as 'A' class). Operational experience
with the first boats of the 'T' class indicated that the bulbous casing,
which enclosed the two external bow tubes, created a bow wave which
impaired vision at periscope depth, and later boats were built with a
finer fore end casing.
As with the 'S' class, the 'T' class proved successful boats but
operations in the Mediterranean, an area for which large submarines were
not suited, led to the heavy losses of thirteen submarines. They were
'(Vickers); 80. Vickers engines Sulzer engines (Cammell Laird); M. A. N. engines (Scotts); Admiralty engines (Chatham). - 84 -
slightly smaller than the 101, 'P' and 'R' classes but dived faster
(60 seconds from full buoyancy), were handier submerged (five minutes to turn 3600), and despite being slightly slower, at 15 Irrots as against
17 knots designed, had a similar endurance of 8,000 miles at 10 knots.
'U' Class
1954 Meanwhile, early in proposals had been put forward for a new design of approximately 400 tons, as a replacement for the ageing 'H' class in the A/S training role, although it was perceived that there might be a use for them in wartime. Therefore, along with the preliminary designs for a new 1,000 ton patrol submarine, the D. N. C. also included a prov- (standard) 81 isional design for a 400 ton submarine. The main stimulus for such a type of submarine stemmed from R. A. (S), and the D. N. C. ' initial submission was based largely on the requirements outlines by
Rear-Admiral Lawrence during March 1934.82
the Progress on design was slow due to the necessity of awaiting the
the 1955 decisions of London Naval Conference allied to the priority given to the completion of final designs on the 'T' class. Thus, it was not until early 1956 that a sketch design was presented, with the expec- tation that if approved the first boat could be included in the 1956 83 the intervening programme. During period, however, the original inten-
for tion of using this class training only, had developed into the prod- uction of a small patrol submarine as aresult of increases in surface
81. See Appendix: E(5).
82. Rear-Admiral (S), N. F. Lawrence to Admiralty, 8 Mar. 1954, ADM 1/9728,169/0.10, P. D. 04459/54, 'Small, Simple Submarine for Anti-Submarine Training., See also Appendix: E(6).
83. Controller to A. C. N. S., 25 Feb. 1936, ADM 19389, M. F. O. 19036,1. -85-
84 and'submerged endurance. The sketch design was adjudged as meeting
Staff Requirements and in some cases exceeding them. Thus, it was calculated that the new submarine would be capable of a diving patrol of seven days at 600 miles from base, in the North Sea or Mediterranean, as late as six months out of dock, instead of the 400 miles originally specified. -Standard tonnage, however, was now around 500 tons and was recognised in the revised Staff Requirements85 as the minimum necessary for good manoeuvring powers and underwater performance, allied to an adequate offensive capability. The offensive armament comprised six-
21 inch bow torpedo tubes (four internal, two external): 'Sufficient to attack a modern capital ship with a fair chance of delivering a crippling blow. '86 However, the need for a good underwater performance was felt to preclude the fitting of a deck gun. Nevertheless, it was accepted that provision could be made to fit a3 inch gun if required.
Surface propulsion was to be by means of diesel electric drive to simplify machinery arrangements-and save weight and space. When surfaced the submarine drew power from electric motors whose generator was directly coupled to the diesel engines, while submerged power was drawn from the batteries. Submerged speed was considered important in this design in assisting evasion of enemy A/S vessels. This also required a very low minimum speed at which the submarine could be kept under control and respective speeds of 10 knots and 12 knots were hoped for, while safe diving depth was considered to be 200 feet maximum. With only minor
84. D. N. C. to Controller, 20 Peb. 1936, ADM 1/9389, M. F. O. 190/56., 1.
85. Tactical Division, 17 Mar. 1936, ADM 1/8835, * T. D. 47/36, 'The 500 tons Submarine. '
86. Ibid. - 86 -
modifications, approval for the final designs was given in June 1936.87
The first three submarines of the 'U' class were ordered in September, under the 1936 Estimates, so as to replace the last of the 'H' class which were then well over-age.
While Government policy still sought to salvage new submarine limit- ation agreements from the wreck of the 1935 Naval Conference, and financial and constructional factors still precluded rectification of all existing deficiencies in the Royal Navy's strength, clearly no substantial increase in British submarine numbers, such as to the 80 total seen as a minimum requirement in the late 1920's, could be achieved for several years.
Therefore in the event of war in the next few years it was clearly a wise policy to incorporate a rapid production facility in any new design, if possible. In the case of the 'U' class, this provision enabled a quick increase in submarine numbers at a decisive period during the early years of the Second World War. The outbreak of the Second World War led to the decision to restrict new construction to the three existing patrol subma- rine, -designs, the 'S', 'T' and 'U' classes, in order to speed production and a further 46 submarines of the 'U' class were built up to 1943, when the ending of naval operations in the Mediterranean reduced the operational need for these boats.
Of all the submarine types proposed, developed and constructed between the two World Wars the patrol model proved the least controversial. The existence of controversy was itself a reflection of the effects of poli- tical and economic decisions manifested in constructional cutbacks and
87. Board of Admiralty, 21 June 1956, ADM 167/94. (Final approval). See also: Board Minute No. 5565,14 May 1936, ADM 1/9389. (Approval of Sketch Design). - 87 -
naval disarmament conferences. The question of submarine abolition is one of policy but the decisions on which models to develop and to what extent, belong to the area of development.
Initially, political decisions, with some reference to military advice, determined the total amount of resources allocated to the Services.
The division of the naval allocation remained the prerogative of Admiralty, with political advice. only then could thought be given to the division of individual categories. Faced with successive reductions in the overall naval budget the Admiralty chose to emphasise the traditional elements of sea power- the capital ship and the cruiser. Even then economic pressure led to the need to reabh international agreement on limiting both categ- ories and expenditure was centred largely on maintaining as near existing levels as possible. Lesser categories suffered severe curtailment and limited development. Falling into this group the submarine naturally faced the problem of insufficient new construction and also of forced discrimination on alternative models.
The patrol submarine presented the least area of difference between the Submarine Service and the Admiralty. The position of the former was quite clear - to press for as many boats and of as many types as that branch of the Navy considered feasible. The Admiralty had to consider two additional factors - the amount of resources for this category and the effects of arms agreements which specifically affected the submarine.
Early recognition was given to the fact that insufficient numbers would be available to satisfy all lines of development and meet all requirements.
The patrol model was recognised as being the most suitable of all the types envisaged, since it would not be as inflexible as the specialist
submarine models in adapting to more than one role -a serious deficiency in an era of retrenchment. - 88 -
The problems of numbers and the effects of political agreements on
designs were common to all categories. In terms of individual development both the Submarine Service, in the person of R. A. (S), and the Admiralty maintained general agreement on the types of patrol submarine needed.
Differences existed over individual aspects of different designs with
correct judgement by no means being consistently restricted to one side.
Undoubtedly the patrol model was the correct one upon which to concentrate
the limited constructional resources available. In terms of the perceived
British need for submarines and the roles assigned to this category, the
patrol submarine was the best choice. Inadequacies in size and endurance
existed in some designs but largely these were imposed by international
political parameters over which the submarine designers had no control.
It was intended, quite correctly, from the beginning that all British
submarines should be able to withstand heavier depth charging and be
capable of diving safely to deeper levels than during 1914-18. This
allowed for increases in the capabilities of foreign A/S forces since
British submarines were expected to operate largely against well-screened
enemy warships rather than slow, lightly defended merchant convoys. New
patrol submarines were also-designed with increased surface and submerged
endurance, good surface speed and sea-keeping qualities, a powerful torpedo
armament, and long-range W/T. Patrol submarines were also by 1939 more
easily and quickly manoeuvred underwater; this had entailed keeping size to dorm *Pe the minimum necessary to meet operational requirements. This
factor and the effects of successive international tonnage limitation
agreements tended to produce two types of patrol submarine - the long-range
for oceanic operations and the short-range for operations in shallow
waters, such as the Mediterranean. However, in areas such as the North
Sea and Atlantic, size was limited largely by the operational requirements
and the depth of water in which the submarine was intended to operate. - 89 -
The type and amount of armament carried by patrol submarines largely stemmed from experience during the First World War. All post-war British submarines were fitted with at least six-21 inch bow torpedo tubes to provide a heavier salvo, as increases in the underwater protection of surface warships ensured that more than one hit was necessary to achieve destruction. Therefore, despite the possibility of advances in A/S tactics by foreign navies, British submarine crews were trained to press home their attacks from as little as 500-1,000 yards. Achievement of sustained torpedo speeds of 40 knots over 6,000 yards by the 1950's brought no change 88 in these tactics. Instead developments in inboard venting were designed to remove the possibility of attacks so close being spotted by the discharge of air as the torpedoes were launched, a factor which was especially vital in clear water areas such as the Mediterranean. Deck-guns were frowned upon by the purists because of the increase in underwater resistance which reduced the submerged speed and endurance of the submarine. These objec- tions were overcome by later developments including streamlining of the gun mounting with the conning tower.
Constituting the largest group of submarines-in the Royal Navy the patrol model naturally undertook the majority of roles. The number of submarines required for each patrol depended on several factors including nature of the patrol, distance of patrol area from base, enemy A/S activity,
in the weather and climate, and special conditions patrol area - depth of water, nature of bottom, navigational difficulties. Offensive patrols, either at a long distance from base or in an area of heavy enemy A/S activity, particularly in a hot climate which reduced the endurance of the
88. Tactical Divisbn, 1933, ADM 186/C. B. 1904, 'Theoretical Investigation: The Use of the Torpedo in Action. ' - 90 -
crew, required the largest number of patrol submarines. The primary object of an offensive patrol remained the destruction of enemy warships. There- fore such patrols. operated irregularly, since they were dependent on information of enemy warship movements. Reconnaissance patrols were intended to be established on a more regular basis. The primary aim of these patrols was obtaining and reporting information on enemy naval move- ments. The submarine had its limitations in reconnaissance since it was
estimated that at most an area of ten - fifteen miles could be effectively
observed and even that only in the most ideal weather conditions. Neverthe-
less, to reduce patrol areas below this level, if several submarines were
operating a patrol, increased the danger of accidental destruction by
friendly submarines mistaking one another for the enemy. The first British
submarine casualty in the Second World War, H. M. S. 'Oxley' was lost in this
manner - torpedoed in error by H. M. S. 'Triton' off Norway on 10 September
1959. Defensive patrols were based on the coastal patrol system estab-
lished during the First World War. However, in view of the singular lack
of success enjoyed by these tactics in preventing coastal bombardments and
raids, it was intended that training submarines would be used in this role
plus submarines in Reserve.
In the 'S', 'T' and 'U' classes the Royal Navy possessed three designs
in service in 1939 which successfully formed the mainstay of British subma-
rine strength during the Second World War. This was more a testament to
the abilities of the naval designers and constructors than to any belief
or consistent support for the submarine at senior command level. Allied
to this were the constant problems of restricted and discriminated resources
for construction and the effects of tonnage limitation agreements achieved
by successive naval disarmament conferences. All these factors combined
to ensure concentration of submarine development and construction on the - 91 -
patrol model. In the prevailing political and economic situations this was the most logical and sensible course since no matter what roles tigere allocated, the degree of viability and success depended upon the number of boats actually in service. Submarine development was never a free agent and its achievements were commendable within the restrictions operating in this period against defence generally gnd the submarine specifically. - 92 -
CHAPTER 3
CRUISER SUBMARINE
The had submarine gained enough success in 1914-18 not only to resist political pressure for abolition but also, within the Royal Navy, to justify
several experiments with specialist submarines, such as the cruiser model.
In 1918 the Admiralty had become concerned about the introduction by the
Germans U-cruiser in of submarines the Atlantic. These boats were armed with two 5.8 inch guns and it was believed that only errors in design had
larger prevented versions of these submarines being brought into service, especially on the major trade routes. The Allies credited the U-cruiser submarines with exaggerated successes and much thought was given to discov- ering means of combating such a vessel if it should appear in any future
Surface conflict. cruisers were ruled out on the grounds that the subma- rine cruiser would merely submerge and then the surface warship would become the hunted than rather the hunter. The vulnerability of any subma-
to damage ignored, rine when surfaced was partly because in the wake of
1917 the U-boat successes of the threat assumed proportions greater than
technology existing substantiated. Whereas in later years A/S forces were
to have the to assumed answer the submarine. In the immediate post-war
the years, only other possible solution was assumed to be the use of development similar submarines. The of a British cruiser submarine had been considered by the Admiralty Submarine Development Committee in 1915 but rejected by the Admiralty because no practical role could be found.
However, as a result of the post-war deliberations a role appeared to
been discovered, have albeit that it was now somewhat tenuous, and this resulted in a reconsideration of the requirement.
the Although period up to the Washington Naval Conference was marked by a severe restriction of resources on submarine development, it proved -95 -
possible-to-obtain approval for design and construction work on the cruiser model. 'Funds were restricted to the production of one experimental boat 1 which was authorised under the 1921 Navy Estimates. Designed to displace
(surface) over 3000 tons 'X. 1' was the largest British submarine built up 2 to that time. The torpedo armament embodied the latest thinking on the need for large salvoes, consisting of six-21 inch boor tubes. No beam tubes were to be fitted as it was calculated that the 900 angled gyro device would enable the bow tubes to be used for beam shots. Unlike the 'K' class fleet submarines the cruiser model was to be equipped with diesel engines. This was because endurance was considered to be a higher priority requirement for this type of submarine. Nevertheless, improvements on existing diesel engine performance were demanded, necessitating the develop- ment of a completely new engine.
Prior to 1914, submarine engine design had been entirely in the
firms. control of private Increases in engine power were only achieved by the limited and cumbersome method of multiplying the number of cylinder units. This situation prevailed up to 1919, although the establishment
the of Admiralty Engineering Laboratory during this period had allowed the Royal Navy itself to develop engine power from the standard Vickers
100 B. H. P. unit to one of 500 B. H. P. Post-war attempts by the Admiralty to return to a limited pre-1914 situation of private firm participation were initially fruitless and costly. However, in late 1920, when the design of the 3,000 B. H. P. engines for 'X. 1' was under discussion, the
Engineering Department of the Admiralty examined designs submitted by. ___ firms (Sulzer five British and two continental and M. A. N. ), in addition
1. Board Minute No. 1268,13 Oct. 1920, ADM 167/56.
2. See Appendix: D(23). -94-
5 to the design produced by the Admiralty Engineering Laboratory. The final decision in favour of the Admiralty design was seen as-marking an official commitment to diesel propulsion for all future British submarines:
the the it fully that. the 'At conclusion of war, was realised ... use of steam in submarines was not sound policy and that efforts must be made to find a high H. P. engine to take the place of steam turbines. '4
However, the level of engine design was also considered unsatisfactory and to be allied to the lack of post-war British submarine development.
Evidence for these assertions was claimed from the example of 'X. l' whose,
'engines when they are satisfactory, will not even meet the requirements for a fast submarine,, and, 'since the war, we have so far only produced H. M. Submarine "X. l", which vessel is already two years behind her proposed date and has not yet carried out satisfactory engine trials. i5
Any suggestion that the-fault lay with the Engineering Department was quickly refuted and the responsibility placed elsewhere:
'The engines of "X. 1" satisfactorily completed their bench trials in May, 1923, easily obtaining their desired power, ' (which R. A. (S) considered inadequate), 'and such defects as have developed during sea trials are in no sense attributable to their particular design, while the delay in carrying out the combined full power trials is due to the fact that the engines cannot obtain their full number the fitted the of revolutions with propellors as ... fact that "X. l" is the only submarine that has been produced since the war is not one for which E. in C. is responsible. It is a matter of policy. '6
Despite this optimism, even the E. in C. could not have seen how much of
an 'evolution' 'X. lt's construction was to be. At the time that this
3. E. in C., Admiral Dixon to Admiralty, 25 Nov. 1925, ADIS 1/8678/64.
4. Rear-Admiral (S), V. H. S. Haggard to Admiralty, 22 Oct. 1925, ADM 1/8678/64,745/S. 195.
5. Ibid.
6. ADM 1/8678/64, Dixon to Admiralty. (See Note 3). - 95 -
order was 'given it was optimistically expected that 'X. l' would be ready
service for by the end of 1923. However, by that date 'X. 11 was no nearer completion than her preliminary engine trials, which were simply 8 described as, 'unsatisfactory', and the submarine was already well behind
schedule.
£Lthough: 'X. l's engines continued to pose a major problem well into
1925,
'it was also said', (that), 'the troubles of her powerful newly designed engines', (were), 'exaggerated. These last were bound to have teething pains, as one would expect from diesels created to replace steam at -comparable speeds and at a time when the former were in their infancy. 19
'Teething pains' must be taken as an understatement since between December
1925 and June 1924 no less than five engine trials were either declared 10 unsatisfactory or simply abandoned Athout any result. Ultimately
1, did her 'X. not complete final trials, including extensive engine trials,
1926, until October nearly three years behind planned completion and acceptance for service dates. In the eight month period from May 1924 to January 1925, 'X. 1' carried out only sixteen days of sea trials.
Diving and engine trials in this series were started on 12 January 1925
and. were scheduled to last six days but were finally extended until the
7. D. N. E. (S) to Haggard, 26 Aug. 1921, Submarine Archives H. M. S. 'Dolphin'.
8. Admiralty, Jan. 1924, Submarine Archives H. M. S. 'Dolphin', 'Preliminary Engine Trials. ' (Submarine'X. 1)
9. A. Mars, British Submarines at War 1959-45. (London, 1971), 18.
10. Admiralty, Submarine Archives, H. T.I. S. 'Dolphin'. List of engine trialsof Submarine 'X. 1 18 Dec. 1923 - Preliminary engine trials (unsatisfactory) 14 Jan. 1924 - Main motor trials 11 18 Apr. 1924 - 11 lt 11 'I 3 June 1924 - Preliminary trials (a Generator Bearing (b, Steering motor burnt out 9 June 1924 - Proposed trial abandoned. - 96 -
29 January. Even then, it was not until 12 March 1926 that 'X. 1' was 11 capable of completing a five hour full power trial satisfactorily. The
Admiralty continued to hold an optimistic view as to the successful out- 12 come of these trials. However, this was largely a question of preser- ving 'face' over what had become an expensive and protracted project. In mitigation some of the delay could be attributed to 'X. l' being an entirely new construction principle designed to fight both above and below the surface. This necessitated a double-hull, on top of which was built an armoured casing to allow the twin 5.2 inch guns to be carried well above the water-line, fore and aft of the conning tower.
The whole question of the gun armament, crucial to the role of the cruiser submarine, could not be easily solved. The original plan had been 13 to fit this submarine with three 4 inch guns but by March 1921 it had been decided to fit a new experimental 5 inch gun, provided the weight of guns, mountings and communications trunks was kept within the weight limit laid down by the D. N. C. This was despite the fact that if an increase in
gun calibre was desired then the 4.7 inch gun, already in use on destroyers, 14 was more acceptable due to ease of supply. Concern was expressed over what was seen as an,
'attempt that is being made to embody purely Gunnery Experiments in this Submarine. In the first place the Gunnery arrangements throughout are of secondary import- the five inch ance ... As regards guns, whether these are 4.7 inch mounted or seems ... a matter of little importance. '15
11. Ibid.
12. Dixon to Admiralty, 25 Nov. 1925, ADM 1/8678/69.
13. D. N. C. to E. in C., 26 Jan. 1921, ADM 138/628A, S. 0467/20, N. M. M., 'Construction of Experimental Submarine;!
14;. D. of G. D. to E. in C., 9 liar. 1921, ADM 138/628A, G. D. No. 54/21, N. M. M., fGun Armament of the Large Experimental Submarine. '
15. Rear-Admiral (S), D. L. Dent to Admiralty, 12 Mar. 1921, AD1,i 158/628A, N. M. M. -97-"
This not only conflicted with Admiralty policy on the relative importance of 'X. 1's gun and torpedo armament but also ignored the fact that a cruiser submarine would be required to operate as a semi-surface warship, unlike the patrol submarine whose main offensive and defensive qualities lay in the ability to operate unseen. Partly as a result of assurances on the gun armament given by Vickers, the final decision was to incorporate 16 four experimental 5.2 inch guns in twin mountings. Rear-Admiral (S)'s concern was undoubtedly a reflection of the Submarine Service's concern over the large resources being allocated to such a specialist submarine when the paramount need was considered to be for patrol models to replace wartime construction and ensure continuity of development.
However, when 'X. 11 entered service in September 1926, with many of its technical problems solved, the Admiralty had finally begun to give serious thought to the possibility that other nations, particularly the
French, might build similar submarines. This had already led to a re-appraisal early in 1925 of the need for the cruiser submarine and in these deliberations finance had also proved to be a major factor; the
conclusion being that, 'as long as economy remains the primary factor we
shall hardly be justified in building in quantity a type of ship whose
contribution to success in battle is at most an indirect one. '17 In the
reconnaissance role it was held that the work could be done better by two
or three patrol submarines. Moreover, it was considered that 'X. 1' was not,
'capable of dealing with anything more formidable than a single sloop or armed boarding steamer or a defensively armed merchant ship. In a retiring
16. Vickers to Admiralty, 17 Jan. 1922, ADM 138/628A, N. M. M.
17. Tactical Division, 19 liar. 1925, ADIJ 1/8705/158. - 98 -
'action she could, at some risk to herself, beat off a single destroyer, and she could put up a good fight against an armed merchant cruiser, but she could hardly be justified in a deliberate attack on either. 118
When the construction of an experimental cruiser submarine had been authorised in 1921 this decision had,, in many ways, appeared as an aberra-
political tion and at odds bath with a requirement to abolish - or at the least constrain - submarines and with a Service need to make the best possible use of diminishing'resources. The fact was that this was the only
submarine type on which Britain had not already carried out research and development. Doubts led to the increasing belief that the only useful role for the cruiser submarine was likely to be against merchant shipping.
Clearly, not only was this a limited duty capable of being performed by the
surface cruiser force but Britain was more vulnerable to such a threat than
any other nation. Nevertheless, during 1924, as part of the proposals for
the submarine category of a ten year construction programme, the Admiralty had actively justified the construction of 'X. 11.
'The development of the Cruiser Submarine may be found to be necessary in order that these vessels working in conjunction with Reconnaissance submarines, may, by means of their powerful gun armament, prevent lightly gunned enemy patrol vessels from interfering with the' lightly gunned Reconnaissance submarines. Should the enemy still persist in hunting our Reconnaissance submarines he will be forced to dissipate his strength, which at the same time would provide opportunities for our surface craft to bring them to action. 119
This ignored the possibility that other naval Powers would have noted the
lessons of the Heligoland Bight and other naval actions and might be better
placed, through being nearer to their own bases than the British, to turn
such manoeuvres to their own advantage. The scenario was further
18. Ibid.
19. Tactical Division, Mar. 1924, ADM 1/8672/230, T. D. 5911. - 99 -
elaborated by the addition of minefields and submarine minelayers. But if support for submarine forces was to be provided to destroy the enemy's major surface units, surface cruisers would have been more realistic.
However, within twelve months there was a reversal of Admiralty support for part of this scenario with the new attitude being that, 'the position of the minefield would probably become known to the enemy and so its value 20 would be lost. '
meanwhile, the commerce-raider role was considered only to be applic- able where. the enemy held the surface command. The Admiralty expected the
Royal Navy to maintain its traditional command of the sea, albeit on a one-power standard, and therefore such a role would be more useful to an enemy's cruiser submarines than to any Britain might possess. The proposal to use such submarines to protect troop convoys was countered by the opinion that smaller submarines would be more suitable. A similar attitude applied to suggestions for 4/S and anti-surface raider patrols. Even the hope of utilising the cruiser submarine in the fleet role was almost non- existent since the tactical value of the fleet submarine was also now in question. However, two alternative roles were considered for which the cruiser model was thought to be possibly suitable. These concerned attacks upon isolated patrol vessels, as well as merchant ships, and the ability of cruiser submarines to operate for three or four months without replen- ishment. If possible, this was calculated as requiring only two 'XI class to carry out the same work as five or six 10' class patrol submarines.
Nevertheless, irrespective of whether or not these functions were suffic- iently important to justify development of the cruiser submarine, clearly the deciding factor was now likely to be finance.
20. D. of T. D. to Admiralty, 12 Mar. 1925, ADM 1/8705/158. - 100 -
Meanwhile, Rear-Admiral (S) W. S. Nicholson now took up the offensive to promote the cruiser submarine. This course of action may have been induced by the combination of favourable reports on 'X. l'21 and the erroneous belief that the submarine could only escape being regarded as an auxiliary vessel if it were capable of operating in a substitute surface warship role. His proposal on the fleet role was vetoed for similar reasons to those set out above and therefore he suggested that if finance was the dominant factor then such a submarine might be useful to the Dominian navies. Recognising that opinion within the Admiralty was hardening against the cruiser model due to cost, the logic employed was that: 'Surface cruisers could not maintain themselves until the arrival of British naval forces, ' (in the rar East), 'but submarines, both large and small, would 22 be of the greatest possible value. ' However, on the subject of imperial naval policy, D. of P., in particular, saw no reason to depart from the
1923 decision that recommended the acquisition of 10' class patrol subma- 23 rines by the Dominions, the reason being that the cruiser submarine appeared to offer no advantage over the patrol submarine in a war where submerged performance would be at a premium and guns of little account.
Cost continued to tell against the cruiser model, since official policy dictated. 'the need for the largest possible number of submarines, within the constantly shrinking percentage of the naval budget allocated to the
Submarine Service. This was reinforced by the opinion that:
21. Captain T. S. Raikes ('X. 1') to Rear-Admiral (S), W. S. Nicholson, 19 Jan. 1924, ADM 1/8671/208.
22. Nicholson to Admiralty, 16 Feb. 1925, ARM 1/8705/158, 119,5.92, 'The Functions of a Cruiser Submarine. '
23. See ADM 116/2311 and ADM 1/8703/118 (C. I. D. 195C) for the 1923 decision of the Imperial Conference. - 101 -
'The size of the submarine cruisers increases the limits her cost and numbers ... On the whole, therefore, it appears that instead of concen- trating on submersible cruisers the correct policy is to build surface cruisers and submarines smaller and cheaper than submersible cruisers but in greater 24 numbers. t
Nicholsons support for the cruiser submarine remained unshaken, however, and he still contended that: 'The best antidote to the cruiser submarine is. the cruiser submarine herielf. t25 Despite having favoured this idea in
the 1918. Admiralty remained unmoved and merely proposed that the matter be raised later, preferably after at least a year. It was hoped that by then all the necessary reports on the performance of 'X-l' would have. been received and studied. However, due to the many delays in construction and trials it sea still proved impossible to reach a final-assessment even by
1926 July and the view remained unaltered that: 'The future of Submarine
l", "X. and the policy with regard to this, type of vessel, will require
thorough very consideration when the various reports on this vessel's capabilities have been received and studied. '26 Nevertheless, in the
the interim weight of financial and tactical factors continued to mount up against further development-; of the cruiser submarine. Therefore, it
decided that was existing submarine policy should be based on the decisions
the reached at Naval Staff conference. on,. '; the necessity for and uses of various types of submarines, ' held on 19 February 1925.
Disillusionment 'X. l' the with and overall concept of the cruiser
to the: submarine continued spread within Admiralty.. This was a reflection
24. D. S. T. D. to Admiralty, 17 Apr. 1925, ADMS1/8703/158.
25. Nicholson to Admiralty, -23 May. 1925, ADM 1/8705/158.
26. D. O. D. to Admiralty, 15 July 1926, ADM 1/8705/158.
I - 102 -
in part, of the disarmament policy then being pursued. The Admiralty was pessimistic about the Government achieving international agreement on submarine abolition but remained prepared to accept both quantitative and qualitative limitations. In the case of the cruiser submarine the question of qualitative limitation was welcomed. IV/hether total submarine tonnage be rationed or not, it will be to our advantage if other nations build
"X. 11"s at a cost of nearly £1 million apiece. No successful case has recently been made out for large "Fleet" or "Cruiser" submarines, though 27 the attempt has been made. ' Clearly'senior naval support for continued development of the specialist submarine was declining. Moreover, the appointment of Rear-Admiral V. H. S. Haggard as head of the Submarine
Service had removed a major centre of support for the cruiser submarine.
Despite being careful to preface his remarks by stating that it was impor- tant to bear in mind that 'X. 1' was an experimental submarine when,
'discussing her role in warfare, or in criticising her present qualities, ' he quickly concluded that:
'The newest type to which she approaches is undoubtedly the Cruiser submarine but, with reference to my predecessor's remarks on this subject, the construction by this country of cruiser submarines to work as such is very strongly condemned. The more we can lead other nations away from the cruiser submarine the better. That they are a potent weapon is very strongly concurred in, but of greater use to our possible enemies than to ourselves. A very few cruiser submarines acting on our main trade routes would engage a vast number of vessels in trying to hunt them down. It is only necessary to visualise the situation in the late war had the "Emden" had the ability to dive. 128
27. D. of T. D. to Admiralty, 5 Oct. 1925, ADII 1/8683/131.
28. Haggard to Admiralty, 8 July 1926, ADM 1 8703/158, 953/S. 110, 'Functions of a Cruiser Submarine. ' - 105 -
This statement, however, seems to make the common mistake. of the period, in assuming that the submarine was capable of similar performance to its surface counterpart. 1,4oreover, Haggard must have been aware that the
German surface-raider successes were achieved prior to the introduction
the belief had of convoy and already been stated that submarines such as any 'X. 1' could not be expected to engage surface vessel larger. than a destroyer. Even an action with a destroyer was considered to be a great 29 risk.
The-weight of tactical and technical opinion was therefore moving. over, 7helmingly against further development of the cruiser submarine and the coup de grace was administered as an indirect result of the failure of the 1927 Geneva Tripartite Naval Conference. Although the failure to achieve major agreements had little effect on existing British plans for
development, overall submarine the realisation. that the future qualitative limit likely to be (surface) was approximately 2,000. tons proved a major factor in the demise of the cruiser submarine in the Royal Navy.. The
however, had decided other reasons, been. by 1925, as the Admiralty made
by that they, 'could clear stating see no reason to recommend any modif- the ications of decision made at the conference presided over by D. C. N. S. on 19.. 2.25., beyond suggesting that the question of building Cruiser 50 Submarines be now laid aside indefinitely. '
Although opinion was clearly moving against the specialist submarine in the view of stringent economic environment, thought was now given to a possible solution. The proposal included combining the patrol/fleet/and cruiser models in one design, albeit with a smaller gun armament than tX. l'.
29. ADM 1/8703/158, Tactical Division. (See Note 17).
30. D. of T. D. to A. C. N. S., 24 Feb. 1927, ADM 1/8705/158, 'Report of Conference on Functions and Requirements of Cruiser and Fleet Submarines. ' - 104 -
Some of the opponents of the cruiser submarine were prepared to give. their support to this compromise: 'The policy to produce a fast enough submarine with internal combustion drive to work with the Main Fleet is still
Such be strongly advocated. a submarine can used ... as a Cruiser subma- rine or as an Oversea Patrol submarine. '31 The idea was doomed to failure as much by the inconsistencies of the different roles of the three models, as by technical and economic difficulties. Moreover, it was recognised. that 'X. l', 'would not be suitable as a Fleet Submarine as her speed is insufficient, ' and: 'She is not suitable for a patrol submarine, being too 32 large. ' The era of the specialist submarine was definitely on the wane.
No requirement had existed for a cruiser submarine. Attempts to produce authorisation for such a model in 1915 had foundered on the failure to. find a practical role. Its birth was an aberration and the longer 'X. l' existed the more incongruous its position appeared. In a time of plenty the cruiser submarine might have survived but in the inter-war period maximisation of hulls was at a premium and the patrol submarine offered the best return. Much of the support for the creation of the cruiser subma- rine in the Royal Navy stemmed from the erroneous and futile policy, which
sought to remove the auxiliary status attached to submarines by securing
acceptance of such vessels as substitute surface warships. However, not only was performance inadequate in comparison and expensive in cost but
gradually re-acceptance emerged that the true advantage and. contribution
of the submarine lay in the ability to operate unseen and unsupported in
enemy waters. The concept of surface gun actions totally destroyed these
31. ADM 1/8705, Haggard to Admiralty. (See Note 28).
32. Haggard to Admiralty, 5 Dec. 1926, ADM 1/8703/158, 955/S. 100, 'H. M. Submarine "X. 1" - Employment of. - 105 -
attributes. Especially when money was getting tighter, the development of a vessel with less capability and higher costs than an existing counter- part had no practical future. The Admiralty, aware of the need to maximise its resources, was glad to accept the political escape route of qualitative tonnage limitation to preclude further development. Any residual opposition was further quelled by reference to the absence of practical roles and the threat posed to merchant shipping of other Powers following the British constructional lead if development was not curtailed with 'X. 1'. - 106 -
CHAPTER 4
FLEET SUBMARINE
One of the most ambitious submarine projects undertaken during the
First World War had been the development of the fleet submarine. The vessel was born from a combination of beliefs that the Germans planned to build similar submarines and that for the submarine to gain acceptance in the Royal Navy it had to be capable of operating with the Fleet. The result had been the 'K' class which had been capable of 24 knots (surface) but only by using steam propulsion with its attendant deficiencies and dangers. Thus, in the period of retrenchment and economy which followed the return of peace, only ten 'K' submarines were retained in service. All those in need of expensive repairs, such as boiler refits, were detailed 1 for the breakers' yards. Work did continue, however, on one 'improved' 2 'K' class - 'K. 26'. Although it had an increased torpedo armament it failed to satisfy the new demand for a fleet submarine with a6 knot advan- tage over the most modern battleship.
'Whether the tactics associated with the operational use of fleet
submarines were sound was a small problem compared to that of developing
a sufficiently powerful propulsion system. The increase in the speed of new capital ships intensified the problem and steam turbines were now
regarded as unreliable and cumbersome. Efforts were therefore concentrated
on producing a diesel engine of sufficient power to allow the submarine to
1. 'K' class disposed of as follows: - 1921 - 'K. 3,7,10-11. ' 1923 - 'K. 8' 1924 - 'K. 15-16. ' 1926 - 'K. 2,6,9,12,22. '
2. See Appendix: D(18). - 107 -
operate with the Fleet. The basic diesel unit developed by 1918 was the
300 B. H. P. design, and the original intention was to use this as the basis for larger engines. Plans to develop more powerful engines by increasing the cylinder size were abandoned because of the problems experienced in attempting to obtain a smokeless exhaust. In addition, it had been found that higher power could be obtained, without increasing the cylinder size, by using a system of air injection. In this area, design and operation of air compressors was considered to have reached a stage where reliability could be guaranteed. Construction was started at Chatham, in late 1918, on a new engine known as the Digit. The first trials were carried out at the Admiralty Engineering Laboratory in November 1919 and proved so succ-
essful that it was decided to base the engines for the experimental cruiser
submarine 'X. 1' on these designs.
Meanwhile, the Admiralty resumed subsidisation of several private
firms with the object of designing and testing engines of 5,000 B. H. P.
However, all such attempts ended in failure and in the case of Vickers,
the Admiralty as well as paying for the unit were forced by contract to
order two engines of only 2,400 B. H. P. Nevertheless, in October 1921 the
tender for two sets of 5,000 B. H. P. engines was accepted, with delivery
promised within a year but in fact bench trials were not completed until
September 1925. Although not built for a submarine they were essentially
of the submarine type and the trials indicated that the engine was unsuit-
able due to exhaust problems. After this series of failures by private
firms the Admiralty restricted future engine development to naval designs.
The situation in Britain was largely mirrored in the other major Powerst
development of submarine engines. In both the United States and France
the largest designs were of 3,000 B. H. P. The Americans were known to be
adapting the M. A. N. design for their 1925-26 programme, while the French
were using the Sulzer design. France possessed a 6,000 B. H. P. engine but - 108 -
this required the addition of a second engine to drive the auxiliaries.
It was calculated. that without this the main engine could produce only
4,800 B. H. P. for direct propulsion.
Admiralty official policy continued to be based on the belief that,
'finality would not be reached by any one design and that a satisfactory leading position could only be obtained and maintained by pushing forward with progressive designs and keeping the experimental stages as far ahead as possible. '5 Thus, while progress was being maintained on the 'Digit' engine, work was undertaken to produce an alternative experimental engine. based on the double-acting two-stroke type. This was expected to develop
was approximately 1,000 B. H. P. per cylinder but it realised at an early stage that the 'Datic' engine, consisting of a number of similar cylinder units required a large submarine hull. There appeared to be no way of
engine without reducing the size of the also reducing the high horsepower.
The hope was that the transition from the experimental stage to the final design would allow the necessary reduction in size without affecting the total power output. Trials of the completed engine were begun at the
Admiralty Engineering Laboratory during July 1924 but despite strenuous efforts the considerable problems arising from these trials still had not been solved by December 1925.
During 1924 the Admiralty had submitted to the Cabinet detailed proposals for a ten year construction programme. In the submarine category, eight fleet models were considered the minimum number necessary, 'to
justify the effort and expense involved in constructing, maintaining and 4 training a special type of vessel. ' moreover, the inclusion of the fleet
3. Admiralty 1924, ADM 1/8678/69, 'The Development of the Internal Combustion Engine for British Submarines. '
4. Board of., Admiralty to D. C. N. S., 5 Mar. 1924, ADMM1/8672/250, P. D. 02004/24, 'Ten Year Construction Programme. ' - 109 -
submarine was deemed dependent on the production of a satisfactory design.
Lack of such a design clearly threw the plans for this type of submarine into jeopardy. A prime requirement was the provision of, 'a cruising speed and endurance equal to that of a capital ship, '5 and this meant,
'at least one knot in excess of the Battle Fleet, but a speed of 25 knots would add greatly to the possibilities of effective use of these vessels. '6
The strength of opposition to any return to the system of steam propulsion was strongly emphasised:
'we do not intend to build any more fleet submarines until the internal combustion engine is developed so as to give sufficient speed to build a submarine that can accompany the Fleet. At present we cannot build internal a submarine with an combustion engine of 7 sufficient speed to be of value as a fleet submarine.
Such a development could only be very costly, biting deeply into the limited resources being made available to the Submarine Service.
Nevertheless, as with cruiser submarines Rear-Admiral (S),
W. S. Nicholson remained firm on the necessity for fleet submarines.
Once again the reason was largely a reflection of the continuing belief in the battlefleet as the final arbiter of maritime warfare. In this scenario, engendered partly by the financial investment in the capital ship, the submarine continued to be regarded as fulfilling an auxiliary role unless it could make a direct contribution to a fleet action. A more practical insight was provided by the view that: 'Fleet Submarines are not a defence against enemy Fleet Submarines, nor are they an
5. Rear-Admiral (S), W. S. Nicholson to Admiralty, 21 Mar. 1924, ADT,4 1/8672/250, 'Remarks' on P. D. 02004/24.1
6. Rear-Admiral (S), V. H. S. Haggard to Admiralty, 5 Dec. 1926, 1/8703/158p ADM 955/5.110, 'Fleet Submarines - Design of.,
7. D. C. N. S., Vice-Admiral. Sir Roger Keyes to Cabinet Naval Programme Committee (C. N. P. C. ), 23 Mar. 1925, ADM 116 3441, '5th Meeting'. - 110 -
'essential tactical unit of a fleet, so that the possession of this type of craft by a possible enemy does not necessitate the British Fleet having them. '8 This view was not designed to restore the submarine to its correct line of development but rather to prevent expenditure at a time of scarce resources. Nevertheless, if it had been assessed in an objective light then much of the development and construction work as well as, tactical thought of the next few years could have been directed into promoting the submarine in roles more suited to the. existing level of technological development. This would probably have resulted in a much earlier general awareness in the Royal Navy of the true contribution that the submarine could make in naval warfare. However, in the proposals for the ten year
the construction programme Admiralty laid the greater stress on the need
development 9 for and construction to be concentrated on the patrol submarine. questions on the possible success of future fleet submarine development
than the could elicit no more statement that the Admiralty remained very 10 hope
1925, During June Vickers approached the Admiralty with the claim to have fleet design based a submarine on new powerful diesel engines, which were guaranteed to produce 23 knots for 1,600 miles, 20 knots for 3,500
9 knots for miles, and 6-7,000 miles. The submarine was to be driven by two tyro shafts, with sets of engines on each shaft. Each set of engines
six (500 B. H. P. consisted of cylinders per cylinder) producing a total of 12,000 B. H. P. The electric motors were rated at 1,600 B. H. P. and armament
8. Tactical Division to Board, March 1924, ADM 1/8672/250, T. D. 5911, 'Fleet Submarines'.
9. Plans Division, April 1924, ADM 1/8672/250, P. D. 02004/24, 'Ten Year Construction Programme', Part III - Submarines, 5and8.
10. Third Sea Lord, Admiral Fuller to Cabinet Naval Programme Committee, 23 Mar. 1925, ADM 116/. 544-1, '5th Meeting,. ' - 111 -
was to consist of six-21 inch bow torpedo tubes, two-4.7 inch and one
40 mm. guns. The Admiralty's initial reaction was that an endurance of
10,000 miles would be required at 9 knots and the proposed torpedo arena- ment was considered inadequate. The Admiralty's examination of these proposals found that the claimed speed of 23 knots was too high for the
12,000 B. H. P. produced by the diesels and that the submerged speed of
9 knots could not be obtained on 1,600 B. H. P. Dissatisfaction over the torpedo armament was reaffirmed; the Admiralty had requested the provision of two additional tubes and Vickers had placed these high in the bow superstructure. The result was that when the submarine was submerged these tubes had to be operated wholly from within the boat and the view was that: 'This position has several disadvantages and has not been 11 adopted in previous submarines. '
However, the main objections to the design continued to centre on the engines. Vickers had never produced a 500 B. H. P. cylinder unit before; their largest design had been for a 375 B. H. P. unit and this was still undergoing bench trials, producing so much exhaust smoke that it would never have been considered suitable for submarine use. The Admiralty felt that there was still a need for Vickers to carry out more experimental work before they could hope to produce an efficient 500 B. H. P. ' cylinder unit. Moreover, doubts were expressed that,
'for a Fleet submarine propelled by Internal Combustion engines to be satisfactory in giving the requisite "Full Speed" and a big endurance at cruising speeds, a cylinder unit of considerably greater power than 500 B. H. P. will be necessary and that an auxiliary charging engine to give economical charging and cruising speed will also be required. 112
11. E. in C., Admiral Dixon to Admiralty, 31 July 1925, ADM 1/8675/21.
12. Ibid. - 112 -
In addition, the Vickers design was considered to have a slow diving capability and an inadequate safe diving depth of about 200 feet. The latest British designs, 'X. l' and '0.11, were capable of diving to 500 feet.
Overall, the final decision remained that the existing design could not, the recommended as one for which an order could be placed. t1Z
Although the Admiralty had briefly subsidised research by private firms immediately after the War, increasing financial stringency allied, to disenchantment with the results produced the view that it was no longer considered desirable,
'to offer financial assistance to private Firms for the research work necessary for the develop- ment of high speed diesel machinery such as is required for H. M. Navy. Recent Admiralty policy has been to encourage private Firms to develop designs on their own initiative by asking for alternative designs when calling for tenders. '14
Close contact was maintained between the Admiralty and private firms on these designs but it was preferred-, mainly for economic reasons, to carry out the majority of experimental work at the Admiralty Engineering Labor- atory. Nevertheless, there was a feeling in certain quarters that, 'in the matter of the development of the Internal Combustion Engine for subma- rine purposes the Admiralty is not keeping pace with other nations, ' and that in order to rectify the situation, 'the leading private Firms be 15 approached on this matter. ' However, the Admiralty held to the belief
that providing constant attention was paid to the progress of high speed diesel engine development there would be no grounds for future criticism.
13. ADM 116/5441, Fuller to Cabinet Naval Programme Committee, 5th Meeting. (See Note 10).
14. Dixon to Third Sea Lord, 17 Aug. 1925, ADM 1/8675/21.
15. Nicholson to Admiralty, 22 Oct. 1925, ADM 1/8678/69, 743/S. 195. - 113 -
Therefore, it was tactfully pointed out to R. A. (S) that he could not be in possession of all available facts on this issue and if he had these 16 would have forestalled any criticism.
Admiralty policy on this issue of engine development had been reviewed again largely as a result of the debate on whether the design for a high speed submarine should be directed towards producing a general-purpose patrol model rather than a fleet or cruiser submarine. Described as submersibles by Rear-Admiral Nicholson, the latter would, it was hoped, use their ability to submerge to arrive unseen in a particular area and would then carry out surface operations. Concern was specifically expressed on whether there was a limit on the size to which such boats could be built; on the degree of habitability over long periods; on the diving time and underwater manoeuvrability; and finally whether the use of Asdic would allow such submarines to maintain formation submerged.
Official policy was still based on laying down the first fleet subma- rine of a new design in 1929-30. However, there was a growing belief that it might prove possible to produce a patrol submarine with sufficient high speed to operate with the Fleet. The result was an increase in pressure for an alteration to the existing construction policy. This was quickly dismissed on technical grounds, at least temporarily.
'Endeavours to increase speed greatly, result always, from the nature of the fundamental laws of ship resistance, in an increase of displace- ment, and there is no prospect that it will be possible to install machinery in the space allowed in 110" class submarines which will propel the vessel at the speed required of a Fleet Submarine. 117
Nevertheless, the C. in C. 's of both the Atlantic and Mediterranean Fleets
16. Admiralty to Nicholson, 17 Dec. 1925, ADM 1/8678/69.
17. Dixon to Admiralty, 20 Nov. 1925, ADM 1/8675/21. -114 -
favoured the fleet submarine. Admiral Madden held that:
'It is of great importance to possess submarines capable of taking part in a fleet action. The need for fleet submarines, indeed, has become enhanced since the war because we can no longer depend upon possessing a numerically superior fleet to that of our potential enemy. Fleet submarines would endeavour to reduce the 18 superiority of the erny battlefleet. r
Admiral de Brock, despite holding the traditional naval view that subma- rives were merely auxiliary vessels, also favoured their use with the
Fleet. 'The Fleet which has submarines will undoubtedly have a great chance of winning a decisive victory than one without these auxiliary 19 vessels. ' In many ways this was an exact copy of the views expressed by Admiral Jellicoe in 1915 when pressing strongly for the development of the fleet submarine. The contribution of these submarines had been so minimal that their demise was expected with the return of peace. Retrench- ment and financial stringency had dictated reductions in the overall strength of the Royal. Navy so that even the pressure exerted by those who advocated the true role of the submarine as being part of the Fleet was beginning to waver by late 1925. An extensive study. undertaken by the
Naval Staff found support only from the A. C. N. S. and D. C. N. S. for such a specialist submarine. Nevertheless,. opposition remained passive and as such proved insufficient to halt the inertial momentum which sustained the policy to lay down one fleet submarine as part of the 1929-50 programme.
The following year a 3,000 tons design was submitted for consideration. power was provided by two engines producing 9,000 B. H. P. each, giving a'-
surface speed of only 20 knots, which was well below the stated minimum
18. Captain C. P. Talbot, 12 May 1925, Submarine Archives H. M. S. 'Dolphin'., 'The Employment of Submarines'. (Paper presented at the Spring Session of the Royal Naval College, Greenwich. )
19. Ibid. - 115 -
requirement. These engines were also capable of no further development since 20 knots was, 'approximately the limit of speed which submarines 20 fitted with this form of propulsion could attain. ' Calculations showed than an increase in displacement to 4,500 tons would be needed to achieve
25 knots on diesel engines. Irrespective of the military reasons, steam propulsion was considered unsuitable, now because of the fact that, 'the expenditure of fuel being as much as four times as great in Steam'engines as in Internal Combustion engines. '21 There was also expected to be a reduction in endurance. Overall, the failure to approach the required speed was recognised as the main disadvantage of this design.
'While 3,000 tons (surface) displacement might not be too high a price to pay for a submarine which was really capable of accompanying the Fleet, it is thought too much to pay for a submarine which could only fulfil that require- ment upon occasions when the Fleet could proceed at a moderate speed. 122
However, the question as to whether the limit of diesel engine development had been reached was disputed.
'The expectation based upon our experimental work is that we shall be able by the employment of the double-acting principle to increase the power per cylinder to a sufficient extent to permit of the aggregate power required to give the necessary speed for a Fleet submarine by the time it is required. i23 moreover, the question of development was not yet considered urgent, since there was at least two years more before the first fleet submarine was due
danger to be ordered. Thus, the of a confrontation between advocates of
20. D. of T. D. to D. N. C. anä E. in C., 27 Nov. 1926, ADM 116/2522, N. I. D. 069/26.
21. Ibid.
22. D. of T. S., Admiral Taylor to Admiralty, 27 Nov. 1926, ADLM116/2522.
in C. to '8 1926, 23. E. Admiralty, , Nov. AD?d 1/8675/21. - 116--
the patrol submarine and the fleet submarine was postponed. It could only be a temporary respite as the steady reduction of resources allocated to submarine development and, construction, allied to the effects of limit- ation agreements stemming from successive disarmament conferences, dictated that fewer submarines overfill could be ordered, although naval commitments 24r remained unaltered. There was also the possibility that submarines would not only be subject to a qualitative limit of 3,000 tons by the
1927 Geneva Tripartite Naval Conference but that British proposals for a limit of only 2,000 tons would be accepted.
However, on each occasion the displacement question was brought up the designers had to face the power and speed limits of existing diesel engines. The general conclusion in 1926-27 was that if high surface speed was required it could probably only be achieved by sacrificing such items
as guns, 17/T, and endurance. These measures ruled out one way of retaining
the fleet submarine in favour,,. by developing a multi-role submarine. A purely high speed submarine necessitated a deviation away from the
'general-purpose' submarine, of which the '0' class were regarded as 'the
in is latest development ... which no requirement. unduly stressed at the
expense of another. '25
In the late 1920'x, however, the fleet submarine was still seen as 26 having a separate role from the patrol model. Nevertheless, the only
major design differences stemmed from the need for a high surface speed,
which was required if this type was to be able to operate with the Fleet.
By late 1926 it became necessary for the Admiralty to convene a conference
24. D. of P. to D. of T. D., 8Dec. 1926, ADM 116/2522,, T. O. D. 6403/26.
25. D. I. E. to D. N. C. and D. of T. D., 16 Dec. 1926, 1162522, AI, I T. 0. D. 640 326 .
26. Admiralty, 1928, AD', 4 186/462, 'Submarine Manual'. - 117 -
to review once more the overall policy on the fleet submarine. Adaption of the cruiser submarine design as an economical way of achieving such a boat was already rejected but the faltering cause of the fleet model was kept alive by those who considered that recent, 'fleet exercises proved the value of submarines capable of tactical co-operation with the Battle
Fleet. '27 However subjective this view it'was one which had to be consid- ered. Therefore, in the hope of providing a solution to this and other aspects of the problem, a preliminary conference was convened on 22 Feb- ruary 1927. Not unexpectedly no final decision was reached at that time and it was decided to adjourn the conference until the E. in C. could produce definite figures on the performance of existing and experimental 28 diesel engines.
Although, in some quarters, it was still confidently expected that the required increase in engine power would be produced, clearly tmtil the performance figures were available no definite requirements on func- tions could be laid down. It had been hoped to produce the figures within
two months but by April Admiral Dixon was reluctantly forced to admit
that there would be a further 'delay in delivery of experimental mater-
ial. '29 What was clear already was that any, 'increase in engine power 30 would be attended by an increase in engine weight and space. ' I,ieanwhile,
Rear-Admiral(S), H. E. Grace pressed for a fleet or high speed submarine in
27. Rear-Admiral(S), V. H. S. Haggard to Admiralty, 3 Dec. 1926, ADM 1/8705/158,955/S. 100.
28. D. of T. D. to D. N. C. and E. in C., 24 Feb. 1927, ADIS 1/8705/158, M. 02889/26,4. ' (Conference attended by D. of T. D., H. of T. S., R. A. (S), D. N. C., E. in C., or their representatives. )
29. E. in C. to D. of T. D. and A. C. N. S., 1 Apr. 1927, AD:,i 1/8705/158,11.02889/26,4.
50. E. in C. to D. of T. D., 2 Feb. 1927, ADM 116/2522, T. O. D. 6403/26,4. - 118 -
any form, being prepared to accept reductions in gun armament and W/T range if this could give the higher speed necessary. However, even with these changes, a speed of only 22 knots was expected. One fact that was regarded as certain was that a speed of only 20 knots would result in a submarine which was, 'neither one type or the other. 131 Although differ- ing in their support for the various submarine models, successive R. A. (S)'s shared the belief that a surface warship capability was necessary to remove the belief outside the Submarine Service that the submarine was
only a auxiliary warship. This ignored the supreme advantage of the
submarine, its ability to submerge and operate and attack unseen. Clearly, if an alternative to the electric battery had been available then a more
fruitful line of research and development would have been to pursue an
increase in underwater speed and endurance rather than surface speed.
However, the existing level of technology precluded this possibility but
the pursuance of high surface speed was equally doomed at that time. Only
with gradual acceptance of this fact were the limited resources available
for submarine development and construction to be channelled into the more
immediately efficient area of improving the endurance, armament and relia-
bility of the general-purpose patrol submarine. Meanwhile, defeat was not
yet admitted on the question of high speed diesel engine development. 32 The Admiralty conference resumed on the 2 November, with the agenda
still that of deciding on the functions and requirements for fleet subma-
rines and if a favourable decision was reached then clearly recommendat-
ions as to design would be necessary and these would have to take account
of what happened at Geneva. The final recommendation favoured the prov-
ision of fleet submarines largely because the submarine-was the only
51. Grace to D. of T. D., 26 Feb. 1927, ADM 116/2522, 110/562, T. O. D. 6405/26,4.
52. D. of T. D. to Admiralty, 15 Oct. 1927, ADM 116/2522, T. O. D. 2685/27. - 119 -
vessel which possessed the element of surprise. How important this element was likely to be in a fleet action, allowing for aerial reconn- aissance, was an imponderable factor. It was clear, however, that a
'high speed' of over 25 knots was unlikely and therefore a speed of just over 20-21 knots was probably the best that could be hoped for. But it was also reaffirmed that a speed, 'in excess of the battle fleet's maximum speed, '33 was desirable. The reduction in other capabilities, necessary to achieve this higher speed, 'was now considered more important. The reason for this and the decision that the fleet submarines would not be restricted to the fleet role were clearly a reflection of the financial atmosphere of the period. E. in C. reported that as a result of the recent experiments, conducted by his Department, he was prepared to design
an engine capable of 5,000 S. H. P., with"a possibility of being increased
to 4,000 S. H. P. with a three shaftärrangement for the various engines
giving a total weight for main engines, motors, auxiliary generators, and
associated machinery of 555 tons. Total power was 9,200 S. H. P. but devel-
opment was expected to raise this to 12,000 S. H. P.
The problem was then passed over to the D. N. C. for preparation of
designs, with the proviso that the tonnage limit was 1,800 tons (standard)
to conform to the Geneva recommendations. Prior to the production of
'these designs the Admiralty had been reminded that the record of previous
design work wgs one of failure to achieve the required speed when the
submarine had finally been brought into service. Certainly, it was
becoming more practical to regard the proposed new design more as a 'fast'
submarine than as a traditional fleet submarine, primarily because of the
restrictions enforced by the limitations of existing diesel engines.
33. D. of T. D. to Admiralty, 4 Nov. 1927, ADM 116/2522, T. O. D. 26 9527 . - 120 -
Having engaged in some private investigating in the Admiralty's Technical
Departments, Rear-Admiral Grace now favoured producing the new design as
a 21 knot patrol submarine which would be capable of a 'certain' speed of
18-19 knots. In addition,
'if the requirement to dive to 500 feet is modified, a maximum speed of 21 knots could be guaranteed with only a very small increase of size and cost, all the other features of the present "0" class still being retained. 134
The resulting submarine was still expected to be capable of some operations with the Fleet. Instead of a pure fleet submarine the emphasis was moving
to a submarine capable of limited use with the Fleet but with-. the ability
to fulfil all the roles of a standard patrol submarine and the advantages
of higher speed. A reduction in the safe diving depth from 500 to 500 feet
had to be accepted however, but this and the sacrifice of the two stern
torpedo tubes was acceptable in order to ensure a speed of 21 knots, while
allowing for less safety from depth-charging that would logically have 55 resulted from the greater depth. The A. C. N. S. still required tobe
satisfied as to the reasons why a reduction in depth should prove accept-
able. The reply was simply that: 'Submarine officers do not visualise any
intentional diving to such a depth as 500 feet, ' and therefore, 'to be able
to dive to a depth of 300 feet is considered sufficient to meet all
reasonable cases. '36 In addition, the proposed alteration in the power to
dive deep were expected to save weight thereby enabling a higher surface
speed to be achieved.
34. Grace to Admiralty, 8 Feb. 1928, ADM 116/2522,, 158/S. 110, S. O. 104-0/28.
55. D. of T. D. to A. C. IT. S., Vice-Admiral Sir Dudley A. R. Pound, 9 Liar. 1928, ADM 116/2522, S. O. 1040/28,1.
36. D. of T. D. to Pound, 21 Mar. 1928, ADM 116/2522$ S. O. 104028,2. - 121 -
Meanwhile, acceptance of a change in the status of the proposed new submarine was signified by the agreement that the requirements should be reinvestigated and that following the results consideration would be given to Rear-Admiral(S)'s proposal for a Staff conference on the issue of high 37 speed patrol submarines. Naval Staff requirements for a fleet submarine and a 'fast' patrol submarine only differed on the question of endurance
(8,500 and 10,000 miles at 12 knots) and diving depth (200 and 300 feet).
The prime argument in Admiral Pound's view against building solely 'fast patrol' submarines was essentially one of money, since the increased cost of these boats over normal patrol submarines would probably result in a smaller number biting built. The other doubt concerned whether or not the
'fast' patrol boats could double as fleet submarines and whether patrol and fleet dispositions would differ causing disruption in peacetime.
Therefore prior to the proposed Staff conference it was also intended to conduct an investigation into the number of 'fast patrol' submarines a. required if they had to be used inOleet role.
The result was that the Staff conference did not take place until the
18 June. Then the prime disadvantage of using the 'G' type as a replace-
class ment for both the '0' and for the fleet'role was pointed out as the x; 32 million cost of such a programme. Moreover, such submarines would require specially trained crews, which precluded their iise for patrol duties. In addition, the requirement of 19 knots was insufficient, ''for
shadowing a fleet without transports. On the other hand, the 19 knot sea- required going speed was more than eras for shadowing and attacking an
expeditionary force. This work could be done-by a less expensive submarine
57. Pound to D. C. N. S., Vice-Admiral-William W. Fisher, 11 June 1928, ADM 116/2522,5.0.5075/28. - 122 -
38 'with a certain speed of 17 knots. ' The conclusion was that two types
of long-range submarine were needed, including a 'fast' submarine, capable
of-fleet work for which twelve boats were considered to be the minimum
requirement and including three reserve boats. 'For oversea patrol work
it was recommended that the "0" type but with a certain speed of 17 knots
be built, building for should ... programme allowing 48 of these to meet
the patrol requirements in an Eastern War. '39 This entailed producing a
submarine force which would consist of twelve 'G', 48 '0', and twelve 'S'
class. However, this programme tended to ignore two important political
factors of which one, the stringent financial policies of successive
Governments, had been a fact of Service planning for a decade. The other
concerned the prevailing attitude towards disarmament, especially further
qualitative reductions in national submarine forces.
In addition to submarine models, future submarine numbers were causing
concern. Under the five year building programme, authorised by the Cabinet
in 1925, the Admiralty had agreed to a construction rate of six submarines
per year and a service life of twelve years for each, which would give a
steady-state force of 72"boats. The policy had been to produce 60 101-'P'
types and twelve 'fleet' type or others. However, by 1928 probable war
requirements were altered to 64 large and six small submarines under-age
based upon certain assumptions which included an increase in national
submarine force levels, counter to Government policy on naval disarmament,
and that after 1929 the annual submarine building rate would go up to ' seven boats. These assumptions were to be-rudely dispelled by the 1950
38. Plans Division to Admiralty, 19 June 1928, ADM 116/2522, P. D. 03054/28, 'Report of Staff Conference on Submarine Requirements'. (D. C. N. S., A. C. N. S., D. of P., D. of T. D., H. of T. S. attended. )
39. Ibid.
40 First Sea Lord, Admiral Madden, 28 June 1928, ADM 116/2522, 'Memo on Future Submarine Building Programme'. (Written for 9 July Conference). See also Appendix: E(9). - 125 -
London Naval Conference. In addition to the question of a new policy of building small 'S' class patrol submarines, the main problem facing the
Naval Staff meeting was to decide whether to continue the policy of
developing a submarine capable of higher surface speed than existing types.
Information before the participants showed British submarines at a disad-
vantage compared to foreign boats, 'and Navy Estimates still under great
pressure.
On the purely technical side, the E. in C. now considered that the
present limit of diesel engine development for submarines had been reached
and. that the only way an increase in speed could be achieved was by, 41 'increasing the number of engines and propellors. ' Rear-Admiral Grace
was very pessimistic about the potential roles likely to be allocated to
the submarine forces. In his attempts to bolster the case for a 'fast'
patrol submarine, he was not above deprecating the capabilities of existing
submarines. Those with an operational speed of 15 knots were deemed as
being unsuitable for anything but, 'the role of floating wireless offices. '42
Vice-Admiral Fisher added, 'that it was doubtful if the "G" class would
be fast enough, '44 for the fleet role. He attacked R. A. (S)'s attitude as
too 'sombre' since, 'even the present speed should enable submarines to
41. ADM 116/2522,9 July 1928, 'Minutes of Sea Lord's Conference. '
42. Grace, 9 July 1928, ADM 116/2522, 'Minutes of Sea Lord's Conference. '
45. Fisher, Sir William Wordsworth (1875-1937), Admiral; 26 1875; Director A/S b. Mar. of. Division, May 1917 - 1919; Staff Mar. Chief of Mediterranean Fleet, 1919 - 1922; Chief of Staff Atlantic Fleet, 1922 - 1924; Rear- Admiral, Nov. 1922; D. N. I., Aug. 1926 - Mar. 1927; 4th 1927 1928; 1 Sea Lord, - D. C. N. S., May 1928 - 50 June 1930; 1928; Ist B. S. Mediterranean Vice-Admiral, Fleet, 1930 - in 1932; C. C. Mediterranean Fleet, Oct. 1952 - liar. 1936; C. in C. Portsmouth, July 1936; d. 24 June 1957.
44. ADI,i 116/2522, Rear-Aämiral W.W. Fisher. (See Note 41). - 124 -
'bring off attacks in many circumstances. '45 The real question remained whether or not the fleet submarine could perform its tactical functions in the face of possible AIS or air attack. Then there was the problem of finance which, the Controller considered, was made more difficult by fluctuations in policy, with first a demand for a submarine capable of
15 knots, then 17 knots and by 1928 a top speed of 21 knots. As the submarines in service became larger and more complex, the costs of main- tenance and repair also rose along with the effects of inflation generally on the value of money. However, this ignored the fact that the development of the patrol submarine had been the most stable policy, compared to the experiments and expenditure allocated to the specialist models. Neverthe- less, financial factors were forcing the reappraisal of all these types and any other new and expensive project.
Although the overall opinion of the meeting remained in favour of fleet submarines, the participants were uncertain whether changing tactics especially air reconnaissance had eradicated the fleet model's usefulness.
The result was genuine doubt on the wisdom of spending money on a new fleet submarine design before there was proof that it could carry out its functions in battle. This would clearly be an impossible situation to tolerate but it was to be rendered hypothetical by the fact that the 'G' class was not able to achieve the 25 knots speed required for a 'true' fleet submarine. The final decision was against the inclusion of one 'G' class in the 1929 programme. However, as a compromise it was decided to carry out further experiments to determine the need for a fleet submarine, 46 as well as obtaining the views of senior: commanders afloat. The Admiralty
45. ARM 116/2522, Rear-Admiral W. W. Fisher. (See Note 41).
46. Admiralty to C. in C. 's Atlantic and Mediterranean Fleets, 21 Aug. 1928, ADM 116/25222 14.02512/28. - 125 -
made it clear that the type of fleet submarine under consideration was not
expected to be capable of operating tactically with the Fleet. The term
'fleet' submarine' was now to be applied, 'to a type whose speed and sea- keeping qualities are such that it is capable of accompanying the Fleet
on passage in oceanic waters. '47 In this context information was required
from the C. in C. 's on whether or not the speed of the 'G' class would be
sufficient for a fleet submarine. The Admiralty now favoured the negative
view and if the opinion from the Fleets concurred, the question became one
of whether the mere ability to accompany the Fleet justified the inclusion
of a number of the I GI class in future building programmes.
Of all the replies received by the C. in C. 's from their subordinates,
one in particular was outstanding from the practical viewpoint. This con-
cluded that the essential requirements in future British submarine policy
were increased numbers with a larger endurance, especially for operations
in the Pacific, since the actions of an enemy were usually influenced by
whether there were submarines in the area rather than the particular
fighting qualities of those submarines. If fleet submarines were required
they were only really useful on passage:
'In action in the open sea they cannot be relied tactical on as a arm ... Their want of excess speed. over the Battlefleet precludes their use. ' Further: 'Many submarine exercises with the Fleet in peace are unreal because the speed used by the submarine is not proportional to the speed which would be used by the Fleet in war. '48
On using 'G' class submarines for shadowing enemy warships the simple
truth, despite the complex arguments, remained that it was ridiculous to
expect any submarines to be able to shadow vessels such as fast cruisers
47. Ibid.
48. Rear Admiral, 3rd Cruiser Squadron to C. in C. Mediterranean Fleet, 22 Nov. 1928, ADM 116/2522,588/0819. (Enclosure No. 3 to 2551/084/107,23 Dec. 1928. ) - 126 -
for lengthy periods. Not only was this an unsuitable role for a submarine but the advent of long-range maritime aircraft was soon to make it super- fluous. However, there. was an overriding fear in some minds that, 'each type of submarine which war experience has shown to be essential should be included in our peace programme, as to neglect any one essential type 49 is likely to prove a very false economy in the long run., If part of this statement is amended to read, 'each type of submarine which war
has to be inessential' then be to experience not shown , one would closer the thinking underlying the fleet submarine debate. Thus, the admission that such submarines might be unable to perform their functions effect- ively in battle could be qualified by stating that, 'conditions may be 50 such that the necessity for this does not arise', and in this event the other capabilities of this type of submarine would justify inclusion in future building programmes. The opinion expressed in this report also considered that the size of fleet submarines might not have such an adverse effect on submerged performance as was often held to be true.
Operational experience With 'K. 261 and 'X. 1', it seems, had led to the conclusion, 'that such a contention is entirely without foundation. '51
The C. in C. 's Mediterranean and Atlantic Fleets indicated that they favoured. the building of a number of 'G' class submarines for use in accompanying the Fleet52 on passage since even if a higher surface speed were possible it would serve only little advantage.
49. Captain (S), lst Submarine Flotilla to C. in C. Mediterranean Fleet, 26 Nov. 1928, ADM 116/2522,016. (Enclosure No. 6. )
50. Ibid.
51. ADM 116/2522, Captain (S) to C. in C. Mediterranean. (See Note 49. )
52. See Appendix: F(1). - 127 -
'Under the conditions to be expected in a fleet action it must always be problematical whether a submarine, which on the surface is susceptible to attack from surface vessels and aircraft, and when submerged is to a consid- erable extent immobilised, would succeed in reaching a position from which it could attack the enemy battlefleet with torpedoes, no matter what surface speed it possessed. Cert- ainly the increased chance it would have of so doing with the aid of some additional 5 knots of surface speed is not considered sufficiently great to balance the disadvantages which a very high surface speed would at present entail- i. e., greater cost, larger size, less mobility. 163
Admiral Brand was more reserved, confining himself to the belief that:
'Submarines which can accompany the Battlefleet and. possibly co-operate 54r strategically with it, may have a very distinct value. ' Admiral Field was positively ecstatic about the 'GI class design which he considered,
would constitute an efficient Fleet submarine since, with the possible exception of attack on the enemy's battlefleet during a fleet action, it appears capable of carrying out the functions which such a submarine may 55 be called upon to perform. ' However, this was a reference to a 'fast' general-purpose submarine rather than a 'true' fleet (or Battle) subma- rine. The latter was now considered either superfluous or, more real- istically, unattainable. The question of a submarine's ability to shadow enemy naval forces brought only a qualified response as this was,
'governed by conditions existing at the time. For instance, whether or no the force to be shadowed has aircraft at its disposal will make a very material difference to the chances of successful shadowing ...
55. C. in C. Mediterranean Fleet, Admiral Sir Frederick L. Field to Admiralty. 23 Dec. 1928, ADP 116/2522,251/084/107, 'Submarines - War Requirements and Characteristics.,
54. C. in C. Atlantic Fleet, Admiral the Hon. Sir Hubert G. Brand to Admiralty, 25 Nov. 1928, ADM 116/2522., 2181/A. F. 005, 'Design of Submarines. '
55. ADhI 116/2522, Field. to Admiralty. (See Note 55. - 128 -
'no matter what excess of speed they possessed. ' However, it was the conclusion, 'that the "G" type design possesses the necessary speed to enable shadowing to be successfully carried out under favourable conditions; any lower speed would reduce the chances to an undesirable degree; a higher speed is not considered justifiable. '56
Overall, Admirals Field and Brand favoured the 'G' class, for fleet duties,
long-range patrol and reconnaissance duties, plus a small patrol submarine,
for coastal and training duties. Although less favourable opinions were
also expressed, the recommendation was that four 'G' class and two small patrol submarines should be built in each of the next three construction programmes. This would cost less than the existing policy of building
six '0' or 'P' class boats annually.
Once again even those whose personal views were against continuation
of the fleet submarine concept were reluctant to order its demise in the
face of the in-Service support and the years of development:
'The very fast Submarine specially designed for tactical the Fleet in battle work with ... has no friends and hence the idea which has held ground since the war that we must develop a Submarine of longer holds this type no ... The general consensus of opinion is that the type "to accompany the Fleet" and the "oversea patrol type" should be merged and that this type should be given as high a speed as possible. The "G" type is accepted as being a satisfactory compromise at the present time because a higher speed is not possible. '57
After further deliberations, the 'G' class was officially classed as
a 'fast patrol' type. By the time the initial designs were submitted it
had been decided that the two engine arrangement proposed by the B. in C.
would be included, a B. H. P. of 7,750 having been guaranteed. This was
expected to produce a surface speed of 21 knots. The higher submerged
56. ADP.116/2522, Field to Admiralty. (See Note 53. )
57. Pound to Backhouse, 15 Nar. 1929, ADM 116/2522, P. D. 0325429,2. - 129 -
speed of 10 knots was now considered possible, by adopting the heavier
type of battery cell as fitted in 'X. l' and by modifying the bridge and
gun structure. Submerged endurance was calculated at 30 hours at 5 knots but only one hour at full speed. Any increase in the latter, even fifteen 58 minutes, was expected to lead to a considerable increase in displacement.
A three engine arrangement, 'would embody but little advance on the subma-
rine building. '59 There were, however, several disadvantageous effects on
the design including weight, space, and maintenance. Therefore it had been
decided to achieve the necessary power by means of additional cylinders
plus supercharging. This system, if successful, also promised the poss-
ibility of further increases in the engine power in excess of design
requirements. Admiral Backhouse, in particular, was convinced that the
right decision was to reject the three engine design.
On the question of limiting the standard displacement to 1,800 tons,
the problem was twofold. In addition to the specific issue of the 'G'
class design there was also the general problem of continuing to accept a
displacement definition which, although agreed to at the abortive Geneva
Conference of 1927, had never been ratified. The adherence to an artif-
icial tonnage limitation was seen as likely to affect the new 'fast-patrol'
design, especially on weight and space required for the engines and
associated machinery. moreover, in this submarine the amount of prop-
ulsive power produced was considered critical, since failure to reach the
design speed of 21 knots and the operational speed of 19 knots would be
seen as destroying its raison d'eire. Both the Americans and the:
58. D. N. C. to Backhouse, 20 June 1929, ADM 1/9300, S. O. 557729,1.
59. E. in C. to D. N. C., 25 June 1929, ADM 1/9500, S. O. 557729,2. (Enclosure to above. ) 150
Japanese were building submarines larger than 1,800 tons (standard) and had others- projected, which added to the pressure for the Admiralty to ignore the Geneva agreement. However, it was estimated that the first 'G' class submarine would take at least two and a half years to complete.
Therefore it was decided that any decision on the general principle would be left until after the next Naval Conference vhich was expected to take place during 1950. However, this decision meant that the first of the new submarine design would have to be restricted to the existing 1,800 tons 60 proposed in order to conform with naval policy.
The Admiralty remained cautiously optimistic about the long-term possibility of producing a 'true' fleet submarine, capable of 25 knots.
This was despite the views of the C. in C. 's Atlantic and Mediterranean
Fleets that even increased speed would not enhance the requirement for such a boat, since changing naval tactics and new factors such as air- craft had cancelled the requirement. Therefore development was to continue on the machinery, 'with the object of obtaining an increase in the H. P. / 61 weight ratio. ' However, the expectation was that such work would take
two to three years to produce enough information to enable a decision to be made and therefore it would be at least five years and possibly longer before a true fleet submarine could be completed. In view of the likeli-
hood of advances in capital ship speed to 30 knots, it was clearly possible
that when a fleet submarine of 25 knots could be built, if at all, it would
have been relegated to the same position occupied by the existing designs
of 21 knots capability.
60. Backhouse to Pound, 1 July 1929, ADM 1/9,30o, S. O. 337729,3-5.
61. Ibid. - 131 -
Whatever types of British submarines were constructed over the foll- owing years there was clearly going to be a problem with overall national tonnage. Proposals at Geneva had limited the British allocation at
40-45 boats. However, the latest Naval Staff requirement was for 60 submarines and within this total the recommendation was for 48 patrol and twelve 'fast patrol' models. Official British naval policy for any future
Naval Conference was to seek agreement on a quantitative limit of 80,000 tons in the submarine category but if possible to press for a much lower limit if the other Powers could be persuaded to agree. In turn this move was expected to lead to the need for a decision on whether the future
British submarine force was to be planned on the basis of numbers or size of boats. On this question the Admiralty continued to be influenced by the belief that for the immediate future large submarines would continue to be regarded as experimental and therefore that it would not, the wise to start on a considerable programme of these without proving the type.
It is of the greatest importance that, what we do build, should come up to requirements and prove reliable and efficient on service. 162 The resulting recommendation was to include only two 'G' class, instead of four, in the 1929 programme. Two more were to be ordered the following year and it was hoped that by the 1951 programme a decision would be poss- ible on, 'whether the type is suitable for repetition in larger numbers 65 and also what the prospects are of the fast Fleet Submarine. ' Clearly, if the future submarine force was to be limited in numbers by international tonnage agreements then it was a disadvantage to allocate a considerable proportion of that tonnage to submarines suitable only for fleet operations.
62. ADN 1/9300, Backhouse to Pound. (See Note 60. )
63. ADM 1/9500, Backhouse to Pound. (See Note 60. ) - 132 -
On the question of (true' fleet submarines, raised by Admiral Backhouse, senior operational commanders were unanimous in their (opinion that a (in submarine of this nature the present state of engine design) was unnecessary on account of its greater size, greater cost and less mobility. '64
development Official policy was to concentrate on producing a submarine
to it capable of a speed allow merely, 'to accompany the Fleet', a clear
to the tG' reference class. Disagreement also existed on the question of whether allocation of tonnage to such submarines would entail their being
for ba used only Fleet operations, whether: 'Such vessels are efficient for performing Patrol Duties if required. 165
However, majority opinion tended to agree with Admiral Bacldlouse,
two 'G' that only class should be included in the 1929 programme, plus 66 two 'R' two is, class, and class. In order to clarify this and other points, especially those raised by the Controller, it was decided to hold yet another meeting of the Sea Lords on 29 July. The proposald included
two 'R' the substituting of class in the 1929 programme but there was opposition to this move.
tI suggest that it will be extremely difficult to include two these of in the 1929 programme in view of the fact that two have been cancelled from the 1928 programme, one of which was laid down and the other on the point of being and that considerable expenditure will be incurred on these for material and labour plus compensation for cancellation. It would seem to be better policy to propose four 'S' 67 class-,
64. Madden to Backhouse, 6 July 1929, . ADM 1/9500, S. O. 3377/29,5.
65. Ibid.
66. Fisher to Madden, 18 July 1929, ADM 1/9300, S. O. 3377/29.
67. Backhouse to Madden, 7 Aug. 1929, ADM 1/9.500, S. O. 337729. - 153 -
Support for these assertions was already available and, ?although the"G" class could be considered as necessary to meet the requirement for a 68 submarine capable of co-operating strategically with the fleet, ' from the policy aspect it was necessary, in order to conserve tonnage, to build only a few large submarines. Opinion, therefore, seemed to be moving in favour of basing future British submarine building on numbers rather than size. Simultaneously the attempt was being made to retain a flexible option, including a limited number of boats larger and faster than the standard patrol type and also a small number of small patrol submarines. The rapid progress to such a decision seems to have been largely prompted by the preliminary discussions leading to the 1950 London
Naval Conference, where further agreement on quantitative tonnage limit- ation was expected. As a precursor to this it was expected, 'that there will be a curtailment of both the 1928 and 1929 submarine construction programmes. 169 Twelve 'G' class were now considered to constitute a
sufficient programme. Accepting that a 'true' fleet submarine was still
a future possibility, opinion favoured including only six 'G' class in
the forthcoming building programmes. However, the indications were that
the annual construction rate might be cut to four submarines over the
next few programmes. The intention was to order two 'S' class per year
which meant that only two 'G' type submarines could be included annually.
If construction was not curtailed then the recommendation was to also
include two 'R' class annually over the period up to 1931, and a further
review would then take place as a result of any agreements on tonnage
limitation.
68. D. of P. to D. of T. D., 16 July 1929, ADM 1/9300, tMemo on Submarine Policy. '
69. Ibid.. - 134 -
Admiral Madden favoured building only one 'G' class, because of the experimental nature of the design but the E. in C. countered strongly that bench trials of the proposed two engine system indicated at worst a speed of 20 knots. The Controller supported this but would have preferred the first of the class being built in only twenty months. However, the effect on the Navy Estimates precluded this move. In deciding whether to recommend the building of two 'G' class submarines it was uppermost in the minds of all those present that a naval disarmament conference was due and, that in the future a certain total tonnage might be agreed to. If that came about the question would then resolve itself into whether 70 larger and fewer, or smaller and more submarines, could be built. '
Meanwhile, Rear-Admiral Grace had totally committed himself to the 'fast' submarine type, even to the extent of being prepared to abandon the 71 building of the standard patrol model. Thus, given the existing restr- ictions on submarine development and construction such as finance, building resources, qualitative and quantitative tonnage limitation, it appears'strange that the non-Submarine Service elements of the Admiralty favoured increasing the types and options in submarine policy, while the head of the Submarine Service was for 'putting all his eggs in one basket' in order to ensure the creation of a limited number of 21 knot submarines.
Undoubtedly the lure of recognition in a substitute surface warship role proved a strong factor.
General agreement was finally reached on introducing the 'G' class in
the 1929 and 1930 programmes but it was considered unwise to build four of
70. ADM 1/9300, -29 July 1929, 'Minutes of Sea Lords' Meeting on Sketch Design for "G" type Submarine and Submarine Building Policy, ' 1-3. (R. A. (S), D. N. C., E. in C., D. N. E. also attended. )
71. Madden, 14 Aug. 1929, ADIM 1/9300, 'Submarines of 1929 Programme. ' - 155 -
these boats annually for a variety of reasons, stemming largely from the fact that this was a new design. The alternative proposal, to build two
'R' class instead- of two 'G' class, giving a programme of six boats with the inclusion of two 'S' class submarines, was calculated to cost an equivalent amount to four 'G' and two 'S' class. In addition, R. A. (S) grudgingly admitted that completing the 'R' flotilla although 'not essential' would be 'desirable'. However, if only two 'G' class submarines were to be ordered initially he preferred the other four boats to be of the 'S' class. On the First Sea Lord's recommendation it was agreed to
order only two 'G' class in the 1929 programme. No agreement could be reached on the alternative proposals to also build either four 'S' class
or two 'S' and two 'R' class. A. C. N. S. Evas requested to initiate a Naval
Staff study of this issue and draw up a statement on future submarine
programmes to be presented to the Board. The initial conclusion was to
include two 'R' and two 'S' class in the 1929 programme. However, Admiral
Madden was persuaded by the Controller of the problems that reintroduction
of the 'R' class would cause and it was recommended to the Board that four 72 IS' class be included in the 1929 programme along with the two 'G' class.
Nevertheless, the advent of the 1930 London Naval Conference was felt as
early as October when the 1929 programme was suspended pending the results
of the Conference. The effects of qualitative tonnage limitation agreed
to under the London Naval treaty meant that authorisation was given for an
annual submarine construction rate of only three. Nevertheless, one 'G'
and two IS, class were included in both the 1929 and 1930 programmes.
72. Board Minute No. 2647,31 Oct. 1929, ADA 1/9300. - 156 -
Thus, in a period of less than three years there had been a decline not only in the design concept, from a fleet submarine to a 'fast patrol' submarine capable of 'co-operating with the Fleet', but also a reduction in overall numbers from twelve down to only a guaranteed two and in annual building rates from four to one. The outstanding reason for this decline had become apparent in the later discussions on the need and capabilities of the 'G' class. Then it had become clear that inter- national agreements were to be sought on quantitative limitation. There- fore numbers rather than size was seen to be the likely determinator of future British submarine forces. Two 'G' class, of approximately 2,000 tons (surface) each were assessed, in a simple mathematical equation, as being equal to three overseas patrol submarines. Therefore, to the naval planners' problems of cost and qualitative limitation, was added this third problem of numbers. The general reaction was inconsistent, at least to the extent that official disapproval of submarines such as the
'G' class, because of their displacement, was coupled with a failure in the early and middle 1930's to use the full amount of even the meagre submarine tonnage allowed.
The tonnage problems for the 'G' class were multiplied in 1950 by 73 increases in weight of machinery and oil fuel. These were largely responsible for an increase in displacement to 1,795 tons (standard) and
(full 2,155 tons load). On 7,750 B. H. P., this was expected to produce only
202 knots but the added machinery weight was caused by E. in C. designing
10,000 the engines to produce B. H. P. and a surface speed of 214 knots on trials. Nevertheless, the final design was put before the Board for 74- approval.
73. D. N. C. to Backhouse, 29 May 1930, ADM 1/9311, S. 0.155/50,1. .
74. Board Minute No. 2729,11 July 1930, ADM 1/9311. - 137 -
Although the 1929 programme finally included one 'G' class ('Thames'), a second boat was not included the following year, priority being given to the building of the first of a class of specialist mi.nelaying subma- 75 rines ('Porpoise'). However, for the 1931 programme it was hoped to rectify the position by including two 'G' class, within the strict con- fines of the maximum three submarines per programme policy. It was even proposed in the provisional 1931 Navy Estimates76 that the ultimate aim should be to build twenty 'G' class, which would have accounted for
56,000 tons of the 52,700 tons allowed under the London Naval Treaty. It is not clear how far this suggestion was expected to be seen as firm policy, since the provisional building programmes for the period up to 1934 included only one or two 'G' class per year. This would have meant a ten to fifteen year time scale before completion of the requisite number of 'fast patrol' submarines. On the record of the past effects of Govern- ment policies and disarmament conference agreements, it could hardly have been expected that such a programme would survive unchanged. Moreover, the proposal inferred a complete discard of the existing type of large patrol submarine, at a time when the effects of the London Treaty allow- ance pointed to the need for a policy producing the maximum number of hulls. Finally, approval was given for the inclusion of only one 'G' class submarine in the 1931 programme, and a proposal to add two 'G' class to the 1952 programme was reduced to one submarine, the prime reason being one of finance. This was the last of the 'G' class to be authorised and. 77 both the later boats incorporated design modifications. Principally
75. See Appendix: D(29).
76. Admiralty, 16 Oct. 1930, ADM 1/8747/82, 'Navy Estimates 1931'.
77. See Appendix: D(28). - 138 -
these included the fitting of new internal air locks to allow use of the new Davis Escape Apparatus, strengthening of the main bulkheads to with- 78 79 stand a pressure of 70 lbs psi, and modifying other equipment. As a result of trials with H. M. S. 'Themes' these boats were now credited with a maximum surface speed of 224 knots and an endurance of 12,500 miles at
8 knots. The latter was given as the prime cause for accepting the reduction in oil fuel stowage caused by the removal of the internal oil fuel tank. Despite the achievement of reaching 22 knots with a diesel engine, maximum speeds of capital ships were approaching 50 knots, and the possibility of further development work on achieving a 'true' fleet submarine, especially with the engines then available, was not considered
1vorth pursuing. Thus, with the exception of further units of the 'Porpoise'
class minelayer, all future British submarine construction was to con-
centrate on medium and small patrol models.
The general motivation behind the fleet submarine concept had been
the belief that to transcend the barrier between an auxiliary warship and
a major unit of the Fleet, the submarine had to form an integral unit of
the Fleet and participate in Fleet actions.
While the concept of steam propulsion might have died by 1918, that
of producing a viable fleet submarine did not. Despite the lessons of
the War, that any submarine ran the risk of attack as much by its own
ships as by those of an enemy in a surface action, the proponents of the
fleet model could claim that since Jutland had been the only Fleet action
78. Board Minute No. 2797,18 July 1932, ARM 167/87, "'G" class Submarine of the 1931 Programme: Legend and Drawings. '
79. Murray (Secretary) to Board, 5 Dec. 1952, ADM 167/87. - 139 -
this was insufficient proof of the invalidity of the concept, especially
as fleet submarines had not been present at the battle. Whatever the
enthusiasm for such a submarine there was no easy route round the major problem - speed. In order to justify its existence in numbers, a surface
speed at least 2 knots in excess of the battlefleet had to be attained.
During the 1920's it gradually became clear that the struggle was to be a
lost one. Not only were further increases being made in the speed of
capital ships but diesel engine development was not going to produce more
than 22 knots on a 2,000 tons hull. Any increase in engine size necess-
itated a larger hull and nullified the effects of the increased power.
Two factors, in addition to capital ship speed, caused the final admission
of the fruitlessness of the struggle. The 1950 London Treaty limited
individual submarine displacement at 2,000 tons, which precluded further
work on the cruiser model as well. Then the quantitative tonnage limit of
52,700 tons, allied to persisting financial stringency, forced a realis-
ation that design, development and construction had to be concentrated
on the patrol models if the majority of roles and commitments allocated
to the submarine were to be carried out.
The decision to close the development of the fleet model was unavoid-
able not only because of treaties and limited resources but also because
the concept was a false one and led away from the true capabilities and
advantages of the submarine which were then found in the patrol model. In
('River' many ways the 'G' class class) can be seen as suitable long-range
patrol submarines, approaching the American designs used in the Pacific
during 1941-45. British submarines lacked the range for this theatre but
then apart from the defence of Singapore and limited minelaying, the need
for specific submarines for the Far East had never been a requirement. The
limited tonnage and resources available, allied to the bulk of potential
operations being confined to short ranges and shallow waters, ensured that
than necessity rather choice ruled both submarine requirements and designs. - 140 -
CHAPTER 5
SEAPLANE - CARRYING SUBMARIN]
Much of the experimentation with specialist types of submarines in the Royal Navy stemmed from the belief or knowledge that similar work was being undertaken by other navies. There was a basic determination among
the construction and design teams within the Admiralty, as well as in the
Submarine Service itself, to stay abreast of the latest developments,
subject to the limitations of finance and the greater priority awarded to
other categories of warships. The experimental seaplane-carrying subma-
rine was a perfect example to meet all these conditions. The initial
justification was based on the hopes of increasing the reconnaissance role
of the submarine. British submarines had proved immensely valuable in
this role during 1914-18 but there was at least one disadvantage to using
a submarine for this purpose. If the submarine was on patrol close to the
enemy coast or in heavily patrolled waters then it obviously could not
operate on the surface. This necessitated reliance on the periscope as
the sole source of information.
'Even with the periscope out of the water to the standard the horizon will not be more than five miles distant, though ships' masts and funnels could probably be seen at a distance of ten or twelve miles in good visibility. Rain or mist immediately reduces periscope visibility pract- ically to nothing, and in any visibility the chances of sighting the movements of enemy air- craft through a periscope, are small. i-
The solution was looked for in the very weapon which was now regarded as
the a serious threat to submarine on reconnaissance patrol - the aero-
plane.
1. 'The Submarine and Reconnaissance', Naval Review, XIV (1926), 306-14. - 141 -
The idea of shipping an aeroplane in a submarine was not a new idea in the Royal Navy. During 1916 two Sopwith-Schneider seaplanes had been accommodated onboard 'E. 22' and an attempt was made to launch a seaplane in the Heligoland Bight from the fore-superstructure of the submarine.
In addition, the Bristol Burney X aeroplane, built before 1914, had been 2 intended in its collapsible form to be stored away in a submarine. In
September 1918, the Admiralty had circularised senior officers for their views on future naval aircraft requirements. On the question of carrying aircraft in submarines, one commander at least was enthusiastic.
'This seaplane All be carried on board our submarines be for be and will used scouting purposes ... It will fitted folding of very small size and with wings ... It will float off the deck of a submarine and it should get off fairly quickly. ' On recovery: 'It could be attached to the deck of the submarine which could then steam at a good speed with its conning tower out of the water. If the Submarine has to submerge the seaplane could be got below very quickly, say in one minute, with a well trained crew. '5
This length of time seemed very optimistic and clearly a submarine commander would be tempted to abandon the seaplane rather than risk the destruction
of his boat and crew, if subject to a sudden attack. The ultimate answer would be a special deck-hangar but this necessitated extensive research and.
design work to attempt to produce a submarine, so equipped, which could
retain all the necessary capabilities for standard patrol duties. more-
over, there was the problem of developing a suitable aircraft which might
only be needed in small numbers. Preliminary proposals for such an aero-
plane were an endurance of three hours at 120 knots, a 250 H. P. rotary
engine, IV/T, and an armament of two machine guns and one 601b. bomb.
2. H. F. King, 'Parnell's Periscope Peto', Aeroplane Monthly, 1 (1973), 6.
3. Rear-Admiral, Harwich Force to Admiralty, Sept. 1918, ADM 1/8540/258, M. 023435%18. (See also Appendix: F(2) ). - 142 -
Despite the problems, there was just sufficient impetus to keep the project alive. Although the D. O. D., Dudley pound, was in favour, the
Admiralty generally appeared less than enthusiastic, displaying the attitude that,
'this idea will never be carried further along such lines, as the low freeboard of a submarine only allows of an aeroplane being carried in the best of weather, and also if the submarine is forced to dive, the machine has to be left floating. The question of carrying aeroplanes inside submarines is, too problematic to be followed up. The great size of the hatch required, and the lack of opportunity of use of the combination of aeroplane and submarine- carrier preclude any experiments. r4
The result was that the concept lay dormant until November 1923. Then
Captain Max Horton, a submarine commander with extensive experience in the
First World War, resurrected the idea and sufficiently interested the
Admiralty for further development work to be authorised. An existing 'M' class submarine was to be converted to the role of experimental seaplane- carrier so as to avoid the expense of building an experimental boat from the keel up. Even so a further two years passed before actual conversion work began. In the interim it was decided that the problem of carrying the seaplane inside the submarine would be approached by building a
special aeroplane, small enough to be accommodated in a deck hangar.
The work of converting 'U 2' was completed during the winter of
1927-28 and experimental trials began. The aim was to investigate the
use of a seaplane not only for reconnaissance duties but also for spotting
and shadowing an enemy Fleet. A major part of the reconstruction had been
to provide '1,1.2' with a hangar for the specially designed seaplane, knovm
the 'Peto' as , which although unarmed, was capable of carrying an observer
as well as the pilot. Equipped with a wireless set, the 'Peto' was capable
4. Admiralty Technical History, Part 21, 'Submarine Administration, Training and Construction. ' - 145 -
of two hours flying at 113 m. p. h. Overall dimensions were a wingspan of
282 feet, a length of 22-2- feet and a height of nearly 9 feet. Designed by Harold Bolas and built by Parnall' s, the seaplane, th filed awkwardly 5 in anything of a seaway, and performance generally was disappointing. '
Nevertheless, in the absence of an alternative this design would be persevered with. The initial idea for launching the aeroplane, consisted of hoisting it onto the sea by means of a derrick. The seaplane would then take off from alongside the submarine. However, during 1926, thought was given to installing a catapult which,
'should be of sufficient power to launch the seaplane into still air at a speed in excess of the minimum flying speed. This is import- ant in all submarines where, on account of low freeboard, it may not always be feasible to steam into the wind. In the particular case of H. M. Submarine "1:4.2", the seaplane is probably nearer the water than it would be in a submarine designed for carrying air- craft in the first place. '6
However, the fitting of the catapult to 'M. 21 still required the inclusion
of a derrick as part of the post-conversion equipment, in order to hoist
the seaplane back onboard the submarine after each flight. The catapult
proved to be,
'something of an innovation, for, although aircraft catapults had been used during and even before the 1914 war, they were not in general service until considerably later, as witness the First Lord's Statement accompanying the Naval Estimates for 1951, thus: "Trials with a number of experimental types of catapult have been continued and it is now possible to proceed with production as required ... Catapults have been fitted in the "Valiant", "Cornwall",
5. King, op. cit., 9.
6. Admiralty, 1 tar. 1926, Submarine Archives H. M. S. 'Dolphin', 11915, S. O. 1185/26, 'Installation of Catapult in "M. 2". ' -144-
2'", it is ' "York" and Submarine 1t} . and proposed to fit them in eleven other vessels during the financial year 1951. " '7
Essentially, the installation in 'M. 2' was experimental with the object of assessing just what could be achieved. 'M. 2' completed sea trials in
October 1928 and then took part in two Spring cruises with the Atlantic
Fleet to gain operational experience.
The Admiralty, however, continued to avoid a final decision. Clearly with a major naval disarmament conference in the offing there were more important decisions pending. Moreover, if the proposals on quantitative tonnage limitation were accepted then the number of new submarines which
could be built would be severely limited. On this basis, pressure was building up to sacrifice the specialist submarines and concentrate the
limited building resources on the general-purpose patrol submarines.
However, the Submarine Service naturally desired to keep as many models
as well as numbers of submarine operational as possible. Therefore, the
Admiralty was reminded that sufficient experience had been gained with
1M. 2' to allow a decision on the future of this submarine and the general
lines on which any further aircraft-carrying submarines should be built.
This naturally depended on it being accepted that this type of submarine 8 would make a useful addition to the Fleet. Despite lengthy correspondence
between the Admiralty and Rear-Admiral Dunbar-Nasmith the attitude
remained 'that a submarine aircraft carrier should not be considered until 9 further experience', had, 'been gained'. Limited experience did not
7. King, op. cit., 5.
8. Rear-Admiral (S), N. E. Dunbar-Nasmith to Captain (S), 5th Submarine Flotilla, 4 Apr. 1950, Submarine Archives H. M. S. 'Dolphin', 97/4.
9. Captain (S), 5th Submarine Flotilla to Dunbar-Nasmith, 9 May 1930, Submarine Archives H. M. S. 'Dolphin', 225625 2. - 145 -
indicate that, 'Submarine "JII. 211, ' was, 'of any value as a fleet submarine in time of war owing to her slow speed of 10 knots and her inability to "0 fly off in a sea of more than three. Although there appeared to be few problems in maintaining a seaplane in an efficient condition onboard this submarine, the important question was whether boats like 'x. 2' would. prove suitable for patrol work largely because their aircraft could only
operate over enemy fortified areas in the absence of enemy fighter planes.
In addition, the time taken to launch and re-embark the seaplane (twelve
and eleven minutes) precluded such a submarine operating close inshore or
in heavily patrolled waters. The final question was whether an aircraft
carrying submarine would be usefully employed in a reconnaissance role
with the Fleet and the only conclusive answer could come from further
trials and experiments with 'M. 2'.
Before making any further decisions on the tactical possibilities of
these submarines the Admiralty sought the opinions of several senior 11 commanders. Design and construction of a successor to the 'Peto' sea-
plane was estimated at three to four years and since 'M. 2' was due to
become over-age in 1933 there was little point in considering a new air-
craft for this submarine, so the question was really one of future require-
ment. However, 'the limitations imposed by the restricted dimensions of
the aircraft are such that it is difficult to imagine that the constr-
uction of a submarine specially designed to carry aircraft to the
detriment of other qualities, is ever likely to be justified. '12 Clearly,
10. Ibid.
11. Admiralty to C. in C. Is Mediterranean and Atlantic Fleets, Rear-Admiral (3) and D. of T. S., 18 July 1930, ADM 116/3484, M. 2566/30. See also: Appendix: F(1). (19 Aug. 1930,1.1.02729/30. )
12. Dunbar-Nasmith to Admiralty, 17 July 1930, ADM 116/3484,784/S. 97. - 146 -
because of the limitation on the numbers of boats available to the subma- rine Service the ability to adapt an ordinary patrol submarine to carry a seaplane was therefore crucial. 'In this connection, experience in "t;i. 2"
that it be impossible to large has shown would carry a machine ... without duly increasing the size of the submarine or to the detriment of other 13 qualities. ' Nevertheless, if it were possible to equip patrol submarines to carry seaplanes, gains were expected in the reconnaissance role. Here it was hoped that the use of an aircraft would enable five or six times the area to be covered than in a normal submarine surface patrol thereby increasing, 'the range of vision of the submarine and so remove the very considerable handicap under which the submarine normally labours in this respect; to act, in fact as an additional, and very powerful periscope. '14
Others were not so enthusiastic and even if increases in the reconnaissance ability of the submarine could be achieved by the use of a seaplane, this was still considered insufficient reason for sacrificing: 'The main advan- tage by the types possessed submarine over other of vessels ... its power 15 of evasion and surprise. ' Therefore the conclusion was that no 'further
construction of this type is desirable in peace, ' and, 'while it is so
difficult to find money for essential types of vessels it is not considered
further expenditure of this nature is justifiable at the present. '16 This practical view appears to have been an isolated one among senior commanders
afloat, where the opinion was that: 'The ability to operate aircraft from
13. Ibid.
14. Dunbar-Nasmith to Admiralty, 25 Sept. 1930, ADM 116/3484,1033/S. 97.
15. C. in C. P,iedi. terranean Fleet, Admiral Chatfield to Admiralty, 30 Sept. 1930, ADM 116/3484,1529/735/4.
16. Ibid. - 147 -
tsubmarines is a most valuable asset for carrying out duties which are othervrise restricted by the lack of mobility and small radius of vision 17 of the submarine. ' However, improving aircraft performance required an increase in its size. Faced. with Government policy to limit the total submarine tonnage available to the Royal Navy, any increase in submarine displacement meant fewer submarines. A further disadvantage stemmed from the fact that the 4 inch deck-gun would have had to be sacrificed to accommodate the aircraft.
'Experience both during and since the war has shown the desirability of a patrol submarine it is carrying a gun armament ... considered that the advantage of carrying aircraft will not make up for the disadvantages of sacrif- icing this. 118
What limited tonnage was available after meeting existing and planned building requirements was considered to be better allocated to construc- tion of patrol submarines. Clearly no tonnage could be spared to construct a new experimental submarine to carry out further trials. Therefore, operational opinion in favour of the seaplane-carrying submarine was restricted to pressing for improvements in the performance and seaworthi- 19 ness of the aircraft to be carried.
that Overall the belief was aircraft should only be carried in subma- rines if they extended reconnaissance ability and could be fitted in
standard patrol submarines. What was becoming equally clear was that with
development continued of more efficient and powerful land based aircraft:
'For many operations it might be possible to provide submarines with
17. C. in C. Atlantic Fleet, Admiral Hodges to Admiralty, 8 Oct. 1930, ADM 116/3484,1516/A. F. 1125.
18. Ibid.
19. ADM 116/3484, Hodges to Admiralty. (See Note 17. ) - 148 -
by from bases. 'reconnaissance ... aircraft carriers or shore '20 Tech- nology was moving against the need for an aircraft-carrying submarine.
Moreover it was accepted that,
'the fitting of a submarine to carry aircraft will always in some degree decrease her general qualities and increase her vulnerability, even if only by increasing her size and rendering her a better Asdic target, ' and, 'the operations in which self carried aircraft are required would form a small proportion of their general work and ... suitable conditions for operating aircraft are likely to be limited. '21
The decision was that further development of a special submarine to carry
aircraft should not be approved and that any development in this area should be based on the ability to use existing patrol submarines. However, since
any container or hangar for the aircraft would have had to be fitted above
the pressure hull of the submarine this introduced several disadvantages
including vulnerability to gunfire or depth charging. The conclusion on
the construction issue was that: 'The only line along which it seems poss-
ible to work is to produce an aircraft of such a small size that the 22 addition of the hangar to the submarine will not affect its main design. '
However, any reduction in size of aircraft affected its speed, endurance
and manbeüvrability, all considered essential in fulfilling its role in
connection with the submarine. Nevertheless, it was hoped that reduction
in size would also have the compensating factor of reducing the time when
the submarine was immobilised on the surface launching or retrieving its
aircraft. The problems of producing a sufficiently small aircraft capR.ble
of meeting all operational requirements, two seater, three hours endurance
20. D. of T. S. to C. in C. Portsmouth, 31 Oct. 1930, ADM 116/3484,2957/14/11.
21. Ibid.
22. D. of T. D. to Naval Staff, 28 Nov. 1950, ADM 116/5484, T. D. 3514/50,1-5. - 149 -
at 70 knots, able to communicate with a submarine submerged at 100 feet, and with a quick rate of climb and. high ceiling, were sufficiently confl- icting to lead to the conclusion, tthat at the present stage of aircraft development they may be impossible to meet. '23
One factor tending to encourage the Admiralty to consider further development was the knowledge that both the United States and Japan tigere
experimenting with submarines fitted to carry seaplanes. Therefore, it eras accepted that, 'in principle all patrol submarines should carry an
aircraft and that this ideal should be aimed at. However, it is not
considered that the time has yet arrived when such a policy can be looked. 24 upon as a practical proposition. ' The conclusion was that further exper- iments and research were required but that it was doubtful if the require- ments could be met by an aircraft no bigger than the existing 'Peto' type. on the model of submarine to carry the proposed aircraft opinion was that,
that be taken is to investigate 'the only action should ... the design of
a "G" class submarine to carry an aircraft. '25 Only then would it be
possible to determine, from the knowledge of the probable sacrifices that
would have to be made in the submarine's capabilities, 'whether it is
worth while building one such vessel as an experiment. '26
The proposal to modify a 'G' class submarine led to two schemes
being investigated of which one was based on the fitting of a hangar,
catapult and crane and the other was based on the Amerihan and Japanese
system which required neither catapult nor crane but where instead the
23. Ibid.
24. D. of P. to D. of T. D., 1 Jan. 1931, ADM 116/548,13 T. D. 3514/50,4.
25. Ibid.
26. ADM 116/5484,. D. of P. to D. of T. D. (See Note 24. ) - 150 -
aircraft was dismantled and stored in a pressure-tight cylindrical box.
The conclusion was that the latter scheme entailed, 'the smaller sacrifice of the qualities of the submarine, but with this scheme the operational 27 value of the aircraft is very limited. ' In particular, the alterations to the 'G' class caused by fitting a hangar were expected to result in a reduction of WY/T range from 1,000 to 400 miles; an increase in the height of the bridge by 52 feet and the displacement by 120 tons; and as a result of the alterations a reduction of-! knot in speed, both surface and. submerged. The alterations required by the second scheme were correspond- ingly less but necessitated development of a new type of aircraft which could be stored in the pressure-tight container with the need to remove the floats, if this scheme was to be workable. Both schemes suffered from the disadvantage of providing by means of the aircraft compartment, 'a large and prominent target which in the event of perforation by the small-
imperil the est projectile ... would submarine and prevent her from submer- ging or if she submerged would probably result in her loss. '28 Therefore the proposal was that: 'If it is contemplated to carry an aircraft in a
this be to the submarine ... should not added "Thames". '29
Meanwhile, trials continued with 'M. 2' until it could be declared that: 'The main technical problem of operating a small floatplane, of limited performance, by means of catapult and crane from a submarine have been satisfactorily solved. '30 However, the limited range of the 'Petot aircraft and the limitations imposed on flying operations by bad weather
27. D. N. C., 21 May 1931, ADM 116/54-84, M. 03946/30,5-7.
28. Ibid.
29. ADM 116 3484, D. N. C. (See Note 27. )
30. D. N. A. D. to D. of T. D., 15 June 1931, ADM 116/3484, 1,1.03946/30,7-8. - 151 -
had not allowed full use to be made of 'M. 2' during the Spring exercises with the Atlantic Fleet. The possibility of the development of a new type of aircraft for submarine use was now considered unlikely before the scrapping of 111.21. Thus financial provision was only requested for main- tenance of the two 'Peto' aircraft available, in the hopes that they would last out until '11.2' was disposed of. The question of aircraft and subma- rine were now tied together, and any reason for not proceeding with one would also determine the other. In the event of further progress the catapult and crane system was preferred as it gave greater speed and flex- ibility of operation.
Meanwhile, the Treasury had been growing sufficiently concerned about the possibility of increased naval expenditure in this field to press the Admiralty for details of the extent of future plans for this type of submarine and its aircraft and Whether or not such experiments could not be postponed as a sacrifice to economy. The Treasury's finan-
cial fears were calmed by the reply that, II'M. 2" is the only submarine fitted with an aircraft and as far as I am able to say we have no inten-
tion of fitting any more submarines in the near future. '31 Nor was it
likely that either 'X. l' or 'Thames' would be converted to this role,
especially since the latter boat was designed largely for speed and the
addition of a hangar it was calculated would affect this. Nevertheless,
the reply was qualified: 'I cannot, however, tie the Admiralty by such an 32 answer, as things change. ' By October, however, no alteration had
occureed in the view, 'that for the present it would be undesirable to 35 fit submarines generally to carry aircraft, ' but developments by other
31. Backhouse to Treasury, 27 Apr. 1951, ADM 116/3484.
32. Ibid.
33. D. of P. to D. of T. D., 10 Oct. 1931, ADM 116/3484) 1.1.03946/30,9. - 152 -
nations were sufficient to prevent any outright cancellation of the experiments since no further large expenditure was envisaged for 'M. 2'.
One final proposal was suggested by Admiral Backhouse, during November, which was to settle whether it was possible to carry aircraft on patrol submarines, by studying the problem in relation to one of the 'R' class.
This was endorsed the following February by the D. of P. and the resulting information constituted the final decision: 'The investigations which have been made into this problem emphasise the difficulty of finding stowage space for an aircraft on such a congested and peculiar type of warship as 34 a submarine., ' moreover, it was not conceded, 'that the value of an air- craft to a submarine is not likely to be sufficiently great to justify any corresponding sacrifice of other qualities, ' therefore, 'further investi- 35 gation of this problem would lead to no useful result.,
A post-script to the limited development of this minor and erroneous concept occurred during January 1952.112.21 foundered while surfacing to fly off its seaplane. The Court of Inquiry finally came to the conclusion that the loss was probably caused by the access hatch to the hangar being left open so that water had entered the compartment below. In addition, it appeared that the vent valves to the aft buoyancy tanks had inadvert- antly been opened and this resulted in loss of buoyancy aft, causing more water to flbod into the hangar and via the open hatch into the pressure hull. Divers found the conning tower hatches open and it was presumed
below that the Captain had gone to investigate the loss of buoyancy and
to these no order had been given close hatches. The Court took this as indicating that the open position of the hatches had contributed to the
34. D. N. C., 9 June 1935, ADM 116/5484,1,2.03946/30,11.
55. D. of P., 19 June 1953, ADM 116 3484,1.03946/30,11. - 153 -
loss by providing a ready vent to the air from compartments below which flooded at an increasing rate through the hangar access hatch as the bow 56 sank.
The desire to extend the reconnaissance range and capability of the
submarine had been sound in theory, especially as reconnaissance constituted
one of the submarine's most effective roles. However in practical terms
the possible marginal gain in reconnaissance range was eradicated by the many development and constructional difficulties, allied to the inadequacies
of the boat and especially the seaplane. Other specialist submarines had proved expensive in resources and tonnage, at a time when shortage of
submarines made adaptability a virtue as well as a requirement. However,
models such as the fleet or minelayer submarines could, in the last resort,
always be capable of operating in the patrol submarine role with reason-
able efficiency. It was correctly realised that neither '11i. 2' or any
successors would be capable of such diverse duties, despite the original
hope that every patrol submarine could be adapted to carry a seaplane,
without reducing their efficiency in any other role. Experimental trials
proved the impracticability of this. Once again, as with the cruiser
model, submarine design had wandered into an erroneous line of development.
Aerial reconnaissance for the fleet was a role which was better left to
the aircraft carrier and which detracted from the submarine's true contri-
bution to naval strategy and tactics. Finally, even if the original
concept had proved sound, the existing level of technology remained
inadequate and the tactical value minimal in relation to the financial
36. D. N. C., 17 IYiar. 1933, AIYA 138/560, N. L. Z., 38/33, National Maritime Museum, 'Report of Court of Enquiry. ' - 154 -
investment. The Japanese found this to be true when despite years of intensive development (resulting in the I class) the contribution of seaplane-carrying submarines to naval war in the Pacific proved to be negligible. The demise of the seaplane-carrying submarine was as probable as its development was half-'hearted and its passing went unmourned. - 155 -
CHAPTER 6
14INELAYER SUBMARINE
The minelayer proved the most persistent of the specialist submarines developed for the Royal Navy during the inter-war period. The British attitude to submarine minelaying during the First World ; jar had been that in the ability, 'of going to positions near the enemy's ports and laying mines there without being observed, ' the submarine was an extremely use- ful vessel, despite the drawback that it was, 'obviously not possible to
carry many mines. '1 Nevertheless, no design for a specialist minelaying
submarine was embarked on during 1914-18; instead several 'L' and 'L'
class patrol submarines were converted to lay up to twenty mines each. All
of these boats were equipped with special mines and these were laid from
vertical shafts. The operational use of these submarines was to lay small
minefields close in to harbour mouths, while the surface minelayers laid
the main minefields further out from the enemy coast.
By the close of the War the submarine was being seen in the public
eye as a future replacement for the surface warship, despite the marked
decrease in efficiency when attempts were made to duplicate the abilities
of surface vessels. Minelaying was one area where the submarine's
ability to submerge continued to be seen as a major advantage, if the
the limitation on number of mines which could be carried was removed., and
this resulted in a decision to, 'advocate the construction of minelaying
submarines. '2 The essential requirements were detailed as a large
1. Admiralty Technical History, Oct. 1921, Vol. 3, Part 21,12.
2. D. of T. D. to Admiralty, 50 July 1920, ADM 1/9227, 'Ideal Requirements for an Internal Submarine Minelayer. ' - 156 -
endurance coupled with a modest torpedo and gun armament so as to gain maximum utilisation of each boat. Thus, the submarine having laid its mines would be able to act as a patrol submarine on its return to base.
Preliminary work on the requirements for an internal submarine mine- layer, with the object of replacing the converted wartime boats, was authorised by D. of T. T.A. during July 1920. The surface speed was to approximate to that of existing patrol submarines and endurance was to be at least 7,000 miles. It was recognised that the main technical problem lay in creating specific minelaying capabilities for the submarine. Thus, the mine outfit was required to be capable of adjustment for depth-setting up to the moment of laying. There also had to be adequate embarking arrangements for the mine outfits and the submarine had to be capable of laying these in a continuous line, spaced at intervals at least equal to the countermining distance of the sweeps of the enemy minesweepers. In addition, the submarine had to be able to lay mines either on the surface or submerged and at high and low speeds. Finally, an ability to dive in at least ten fathoms was required. Length was not to exceed 250 feet, which matched 10.1', while accommodating 40 mines. Armament was to consist of two 4 inch guns and six-21 inch torpedo tubes, which can hardly be
the described as modest and matched 'L. 50' class, then the most heavily armed British patrol submarines.
The requirements were approved by D. of P. and forwarded to the
in 1920. Permission D. N. C. August was also requested to include the cost
in the 1921-22 of preliminary experiments Sketch Estimates. The cost was to be limited to an amount sufficient, 'to proceed with development only at the normal peace-time rate, '5 and was approved in November 1920. At
debate this point there ensued a on the merits and type of gun armament
3. Admiralty Technical History. (See Note 1. ) - 157 -
to be fitted. Although D. of G. D. agreed with the proposal for the
4 inch calibre as the main armament, he was not so happy about the omission of any A,/A guns because of the clear threat now posed by aircraft acting in the A/S role against submarines. This unease was not shared by the
Head of the Submarine Service, especially if the provision of 4/A armament meant a reduction in the main gun armament. However, as D. N. H. pointed out, both attitudes were superfluous since a minelayer's primary role was to lay mines. Moreover, the addition of a gun armament would affect the underwater endurance of this type of submarine. Nevertheless, it was admitted that there were situations where a deck-gun was necessary to the survival of the submarine and therefore a possible solution would be to fit the gun on a disappearing mounting aft of the bridge.
These discussions were reduced to a scholastic level by the halt on all submarine development and construction by the preparations for the
Washington Naval Conference. Restriction of financial resources was an additional factor hampering development work and not only in the submarine category. Taken together these points meant that even when the policy of
abolition failed the, 'complicated problem of minelaying submarines, ' would be further, 'delayed by the great pressure of work on Submarine "X. l", the
design of, ' the, 'new patrol submarine and the ordinary current work. 14
Despite the general difficulties thirteen designs meeting the Staff Require-
ments for a submarine minelayer were submitted by 1923. The list was
to two basic types including quickly reduced the new requirement that the be inelaying tubes should capable of withstanding pressure at 200 feet.
The two groups of designs were divided into those which favoured
tubes positioning the minelaying aft and those which sited the tubes in a
central position. The total number of mines carried remained at 40 and
4. S. of M., 1923, ADM 1/9239, 'Report and proposals on Internal Submarine Minelayer. ' - 158 -
the laying was now to be expected. to take place at any speed between 4 and
15 knots. Positioning of the tubes in the extreme aft compartment of the submarine meant that the large variations in weight caused by the mine- laying could lead to difficulty in boat-handling. This problem was considered unlikely to arise if the minelaying tubes were centrally located. Moreover, the intention was that the mines would. be laid more slowly from the central position, allowing the trim of the submarine to be adjusted as the mines were laid. Final design selection also depended.
on whether a large number of small submarines would be more satisfactory than a few large boats, because of construction time, cost, number of
the areas to be mined, and operational radius required.. It appeared
that, in order to meet all these requirements, the positioning of the
mine tubes aft would result in a submarine far larger than any already built. Overall length would have been 420 feet and the pressure hull
24 feet, displacement diameter while was expected to be 4,500 - 5,000
tons. Despite this the Superintendent of Mining was firmly of the opinion
that the design incorporating a minelaying compartment at the rear was the
one most compatible with the Naval Staff Requirements.
D. N. C. favoured the alternative designs due to several constructional
the fact that the advantages, including overall dimensions closely matched.
those of 'X. 1'.
'The auxiliary engine room in Submarine "X. 1"" is 40 feet long and if the guns were omitted in that vessel another 18 feet of length would be available which with the omission of the auxiliary engines would result in a length of 58 feet being left available against 59 feet of Scheme L. The diameter of the pressure hull being 194 or less than the 20 feet of Scheme L. A vessel such as "X. 1" would therefore very nearly suit this scheme and probably it could be reduced by about 200 tons displacement leaving a surface displacement of about 2,600 tons. 15
5. Ibid. - 159 -
There was an alternative design based on the new ' 0' class patrol subma- rine but alterations to meet the minelayer requirements would have increased the length from 250 to 530 feet and the displacement from 1,500 to 1,900 tons. These figures tended to confirm D. N. C. in his choice of Scheme L but the Director of Tactical Division disagreed and proposed that the
Naval Staff Requirements be amended to. confine the size of the projected minelayer to'arouna that of the patrol submarine. There was also the problem caused by the alteration of the mine outfit from the moored variety to the buoyant combination. Although it was hoped to find a
solution, if the design displacement could not be reduced below 2,600
tons (as in Scheme L) then this was calculated as precluding any further
development of the buoyant combination.
The majority of Heads of Departments favoured a larger submarine than
the 10' class design, assuming that the displacement could be restricted
to 2,500 tons. In order to clear the impasse a 'conference was proposed,
attended by the relevant parties. The agenda was also to consist of
Scheme C. plus an alternative compromise scheme and included consideration
of types of mine, buoyant or non-buoyant, to be carried in the proposed
minelayer. This item proved to be the easiest to reach a decision on due
to the fact that the object of submarine minelaying was to lay a minefield.
unseen. One person'. at least, Rear-Admiral Sinclair, was certain that the
buoyant combination was unsuitable and that unless the Admiralty developed
a non-buoyant mine combination there was no use in even considering subma-
rine minelaying. Qualified support was given to this view by those
actually responsible for mine design. However it was considered that,
'it was quite possible, without any very great difficulties, to produce a satisfactory type of hydrostatic combination, which, with a release arrangement to release the mine before it reached - 160 -
Zits crushing depth, could be used in depth (The up to 140 fathoms. existing submarine )i6 mine, ' (was), 'limited to 60 fathoms.
modification to the Requirements meant that the aim was now to attempt as far as possible to give the final design, 'the attributes of an over- seas patrol submarine, with the addition of minelaying equipment. '7 In addition to adoption of as many features and capabilities of the patrol model as possible, endurance of 7,000 - 10,000 miles at cruising speed was required on a submerged displacement of 2,500 tons. IQinelaying capability was to be altered to allow groups of ten mines to be laid at speeds below 8 knots instead of. the original requirement of 15 knots. liaximum operational depth was now restricted to 200 feet, calculations showing that the minelaying tubes would be incapable of withstanding a deeper pressure. Meanwhile, the proposals for Scheme L had been modified to also limit the displacement to 2,500 tons. The number of mines were reduced to 36 with each being large enough to allow for a charge of
520 lbs. 'A variant of the moored mine was preferred to the buoyant
combination model; it would have similar tide resisting qualities and
some reserve of buoyancy to allow extra fittings to the mine. One scheme which did not, 'preclude the use of a buoyant combination, if the use of
such a combination from a submarine becomes feasible, '8 was Scheme C.
the laying This also allowed for of groups of twelve mines with no speed
restriction and required a submarine of only 2,000 tons. Despite this
the Conference decision was., 'to abandon any consideration of laying
buoyant combinations, ' from a submarine and,
6. D. T. M. to Admiralty, 22 June 1923, ADM 138/650, (N. ), National Maritime Museum M. M. 'Report of Conference on New Submarine Minelaying Equipment.
7. Ibid.
8. D. of T. D., S. L. Willis to Admiralty, 51 May 1925, AD1,f 1`9259. - 161 --
'it was agreed that any schemes providing for laying of mines from a compartment near the stern need no longer be considered, in view of the great advantages to be obtained from a submarine and constructional point of view, by placing the mining compartment in the 9 mi.dships portion of the submarine. '
On construction, the hope was that the first of the proposed internal submarine minelayers could be ordered during the 1924-25 programme. This was quickly denied. 'No provision has been made in the "Programme of
Construction and Reconstruction" now under consideration by the Board for 10 the laying dotivn of a minelaying submarine in 1924/26. t If design work could be proved to be sufficiently advanced then the Admiralty held out hope that such a submarine would be ordered later, 'in order that trials may be carried out and the type tested as early as possible. '11 Progress on design work was considered to be crucial and concern was expressed that after three years of study no final design or construction plans were available. The blame was placed either on the mining School, for design delay, or the Naval Staff for frequent alteration. of the Require- ments. Despite this, the decision was that the original Requirements were 12 to be replaced by an entire new set. Therefore progress towards a final
design was evidently not going to be rapid.
Although the internal minelayer designs were preferred it was agreed
to postpone construction plans, in order to alloy further experiment3 with
to develop improved converted submarines minelaying arrangements and this
led to a re-investigation of the. external submarine minelayer designs. The
9. ADM 138/650, 'Conference on. Nerr Submarine Minelaying Equipment. ' (See Note 6. )
10. D. of P., 20 July 1923, ADM 138/650, N. M. M.
11. Ibid. _
12. D. N. E., D. L. Dent, 3 July 1925, ADM 138/650, N. M. M. - 162 -
concept had been that originally proposed by Captain Horton in November
1925 but it was not until March 1925 that the proposals were re-examined.
The external model was presented as a means of increasing the number of mines which could be carried. In 1923 the Admiralty concluded that the concept was too experimental to proceed with and be certain of a success- ful outcome. Nevertheless, now the,
'proposal was fully investigated at Blockhouse, (S) and was warmly supported by R. A. (Rear-Admiral 17. S. Nicholson), who succeeded in obtaining approval, in spite of the objections of the technical departments. As a consequence, the internal submarine minelayer investigation was officially dropped in 1925.113
A contributing factor had been the problem of attempting to produce an internal minelayer design within the revised Naval Staff Requirements.
Meanwhile, in order to investigate the external minelayer concept, 114.31 was to be converted to an experimental minelayer. However, since the design work on an internal minelayer had been in progress for five years it was decided that this work should be carried through, in the hope that it would be possible to make a comparison of the two systems before sel-
ecting a final design.
Before conversion work on 'H. 3' could take place it had to be
decided with which type of minelaying equipment the boat was to be fitted. (S), Rear-Admiral V. M. S. Haggard put forward two proposals based either
on the system of carrying all mines on two lines of rails running fore and
hull discharging aft over the pressure and over the stern, or on the system
line into two (four of dividing each sections sets of rails - 25 mines
per set). The foremost pair discharged mines before the conning tower
and the after pair discharged abaft the conning tower, the mines being run
13. Naval Staff, July 1920, ADM 138/72, N. M. M., 'Proposed Naval Staff Requirements for Minelaying Submarines - Appendix II: Submarine Minelayers, History. - 163 -
from aft forward. Although Haggard preferred the latter system he had to admit that there were problems with the discharging of the aft mines forward. Therefore, despite accepting this system it was decided to make alterations and experiment with the forward section discharging mines near the conning tower and the aft section discharging over the stern while the submarine was submerged. Delays persisted in producing a final design and restored some support for the internal design based on earlier reports, 'of a remarkable German design of internal submarine 14 minelayer, carrying 104 German mines on a displacement of 1,530 tons.,
Despite objections from D. N. C. the Admiralty appeared inclined to accept such a design as feasible.
These delays and new developments led to yet another conference on submarine minelayer design; three major points carne under consideration.
'(a) Whether a design of Internal Minelaying Submarine should not be investigated now, observing that if the "P,S. 3't trials are not successful, we should be left in the air at the end of 1928. t(b) To consider on what lines a design of external submarine minelayer would proceed, on the assumption that the "M. 31" trials will prove satisfactory. '(c) To consider what maximum of submarine is permissible, and thereafter to consider the Staff requirements in relation thereto, and the compromise which may have to be made between mine capacity and other desiderata. '15
A few months earlier, at the 1927 Geneva Tripartite Naval Conference,
provisional agreement had been reached on the maximum submarine displace-
ment of 1,800 tons, by accepting that:
'The standard displacement of a Submarine is the displacement of a vessel complete (exclu- sive of the water in non-watertight structure),
14. D. N. C., 16 June 1925, JDM 138/560) 3-0991/25) N. M. M., 'Conversion of 11M.2" and "1,1.3": Conversion of "M" class Submarine into a Minelayer. '
15. A. C. N. S., 2 Nov. 1927, ADM 1/9291, 'Report of Conference on Design of 1,Tinelaying Submarine. ' - 164 -
' fully mam-led, engined and equipped ready f or sea, including all armament and ammunition, equipment, outfit, provisions for crew, misc- ellaneous stores and implements of every description that are intended to be carried in war, but without fuel, lubricating oil, fresh water, or ballast water of any kind on board. t16
Acceptance of this limit and definition meant that all previous agreements on the displacement of the proposed minelayer submarine had to be re-examined.
The logical alternative was to attempt to modify the '0' class design without excessive increases in displacement. The Geneva definition of standard displacement reduced the '0' class, on paper, from 1,710 to 1,540 tons and the necessary modifications to minelayer status were calculated to result in a submarine of 2,000 tons, trhich equalled a displacement of
1,750 tons under the Geneva definition. Prob ablg. speed was estimated as
10,000 16-17 knots and endurance as miles at 8 knots. The total number of mines to be carried was about 40. In at least one quarter there gras
strong opposition to the construction of any minelayer whose displacement
exceeded the '0' class since, 'for operations off the enemy's coast a 17 submarine exceeding "Odin" in displacement was undesirable. ' The
other delegates agreed that, 'the dual functions of minelaying and patrol
could not be allowed for in an "internal" type on "Odin's" displacement'
and since great sacrifices were necessary to achieve a successful internal
minelayer the recommendation was, 'that further consideration of the
internal submarine minelayer should be postponed until the results of
trials are known. 118
16. Tactical Division, Oct. 1927, ADM 1/9291, 'Agenda for Conference to be Held in Accordance with A. C. N. S. Minute of 3.10.27. - Design of Minelaying Submarine. '
17. Captain Phillips (representing R. A. (S). ), 2 Nov. 1927, ADM 1/9291, 'Conference on Design of Minelaying Submarine.
18. .ADM 1/9291, 'Report of Conference on Design of Minelaying Submarine. ' (See Note 15. - 165 -
Irrespective of the merits of the alternative system any decision was subordinate to the economic factors controlling the amount of constr- uctional resources available to the Admiralty. Thus, all available resources in the submarine category were allocated, with priority going to the patrol model. Immediate construction of a minelayer submarine was clearly precluded by the statement that,
Iin the submarine building programme, the provision of an adequate number of the overseas patrol type of submarine was of primary import- ance and that until requirements in this direction had been met, the laying down of a Submarine mine- layer which did not also conform to patrol require- ments was not recommended. '19
irrespective of the decisions of the conference, Rear-Admiral (S), H. E.
Grace considered that the external minelayer seas preferable to the
internal system because,
tan external minelayer could probably be evolved retaining all or nearly all the main features of the "Odin" class and thus be available for reconnaissance duties after, or when not minelaying, whereas, an internal minelayer, if limited as to size, would be of little use except for actual minelaying. r20
Underlying this view was the natural desire of the Submarine Service, in
financial a period of and constructional stringency, to utilise its
to the submarine force maximum. Little could be done to alter existing
be models but pressure could applied to new designs in the hope of securing
a multi-role boat.
However, if the trials of 111.51 proved successful then provisional
that, 'it be agreement was might recommended to lay dorm one minclaying
19. D. of P., 2 Nov. 1927, AW 1/9291, 'Conference on Design of Minelaying Submarines. '
20. Rear-Admiral (S), H. E. Grace to Admiralty, 1 Dec. 1927, ADM 1/9291, 'Comments on Conclusions of Admiralty Conference on Design for New Minelaying Submarine., - 166 -
'submarine in 1929 and subsequent years, subject to the tentative 21 programme of sic submarines per annum being approved. ' Meanwhile, clearly if the minelayer design was to be based on the '0' class displacement, rather than a larger submarine resulting from the '15.5' trials, then certain major components would have to be omitted. These included the stern torpedo tubes, guns, Asdic, and a reduction in diving depth from 500 to 200 feet. The seriousness of these omissions meant that although the recommendation had been for research into designs based on patrol submarine displacement, the final decision was to depend
on the results of trials with '14.3'. The Admiralty decided therefore,
, to defer investigation of a new design of Minelaying Submarine until
the end of the present year. '22 Moreover, the Submarine Section of the
D. N. C. 's department was already'fully committed to development work on
fleet submarine and 'fast' patrol submarine designs. The most that could
be allocated to the minelayer problem was work on the conversion of 114.31.
However, the expectation was that by early 1929, 'more time should be
available for the consideration of the minelaying design and by that time
""M. 3" should have had sufficient experience to indicate if her arrange- 25 ments are sufficiently successful to be worth repeating. 1
Various conversion problems meant that the trials were unlikely to
begin until January or February 1929 which left little time for preper-
ation of designs if the first of the new minelayers was to be included in
the 1929 programme, as planned. Nevertheless, the expection was, (that
21. ADd 1/9291, 'Report of Conference on Design of 1Linelaying Submarine. ' (See Note 15. )
22. Admiralty to Grace, 20 Apr. 1928, ADM 1/9291) S. 0233/28.
23. D. IT. C., 7 liar. 1928, ADIS 1/9291, S. 0.2533/28. - 167 -
'there would still be time to prepare the design on the assumption that tenders would be called for in November 1929. '24 However, in December, it was suddenly announced that delays in design of minelaying gear prev- ented any trials with 'M. 3' until the end of March at the earliest. It was calculated that the decision not to place an order in 1929 would
enable more thorough trials with '11.5' than had been possible under previous arrangements. The result was expected to be the construction of
a more satisfactory submarine than if the existing designs were rushed 25 through to completion. Confirmation of this decision was announced the
following month. 'Their Lordships have decided to await the completion
of H. M. Submarine "M-5's" trials before considering the design of a new 26 minelaying submarine.
When trials finally got underway the main emphasis was placed on
developing a more efficient means of spacing the mines.
'The usual method of spacing is by a time interval, which, under conditions of lour speed and strong tides, may give results of extreme inaccuracy. It is even thought possible for one mine to be dropped on the top of another. When submarines carried only 14 or 16 mines there was a tendency for these to be laid in scattered groups with a very large spacing; but now that "M. 3'" can carry 100 mines it is thought desirable that she should possess the means of spacing them with fair accuracy. '27
This gras a crucial point since the proposed new designs had been intended
to carry only approximately 40 mines. The method chosen for the trials
was a form of taut-urire gear and the idea was to run out a 'string' of
24. D. N. C., 14 Nov. 1928, ADM 1/9291.
25. A. C. N. S., Vice-Admiral Dudley Pound, 18 Dec. 1928, ADM 1/9291.
26. Admiralty to Grace, 7 Jan. 1929, ADIM 1/9291.
27. Captain, H. M. S. 'Vernon' to Admiralty, 29 July 1929, ADP,,1/950,1,11.1097j29, 'Spacing of Nines from Submarines. ' - 168 -
mines on a measured length of wire at set intervals and then cut the wire
as the last mine in a group was laid. Successful trials were held during 28 early December, resulting in the recommendation that a special taut-wi. re 29 machine be designed for submarine minelayers. Endurance trials with mines on board were scheduled for 1930 and the equipment tests were planned
to conclude in March. Following this, it had been intended that 'M. 3'
should be assigned to operational duty with the Fleet. This mine1oying
role was vetoed, it being pointed out that,
11115.3's" minelaying equipment was fitted as an experiment, with a view to the possible evolution of an external minelaying submarine from the experience gained. in "ßi. 3", and it is doubtful whether it will be possible ever to produce the maximum obtainable efficiency in an old submarine, to which has been added an experimental minelaying equipment. 150
Before any further trials could take place an agreement was concluded
at the London Naval Conference which confirmed the maximum submarine 51 displacement as 2,000 tons. In addition, Britain was restricted to a
total submarine force of 52,700 tons and in order to comply with this
figure it was necessary to scrap 17,000 tons. Clearly experimental and
specialist submarines were most vulnerable. 11.51 had now completed her
the for trials and results were ready presentation to the conference called
28. Tactical Division, July 1930, ADM 186/476., C. B. 3002/29, 'Progress in Torpedo, Mining, and A/S Warfare (P. T. PMI.A. S. ) 1929. '
29. Rear-Admiral (S), M. E. Dunbar-Nasmith to Admiralty, 1929, 1/9504. (Concurrence 20 Dec. ADM in remarks of Captain of '14.3' and Captain (S) H. M. S. 'Dolphin'. )
30. D. iJ. E., 19 rTov. 1929, ADM 1/9505, T. 0.615/29, 'Submarine "M. 3". '
1930,11DM 31. Naval Staff, 7 Feb. 116/2748, 'Documents on the London Naval Conference - Position at the London Naval Conference, 1930, of His Majesty's Government in the United Kingdom, Part II, Para. 8. ' - 169 -
to decide,
'the future of the vessel as well as the design of'future minelaying submarines. As regards the future of "M. 3", the conversion of the vessel into a minelayer has very seriously impaired her characteristics as a submarine and it is considered that. extensive alterations will be required to overcome these defects before she is fit to join the Fleet. '32
It was, 'tentatively proposed that 11M.3" should be disposed of in 1953,
in which year she reaches thirteen years of age. '33 The decision was
only tentative because the Admiralty considered that there still had not been adequate time to assess which submarines were essential. This factor
vra.s important because of the poor replacement rate from construction, even
judged by the amount of tonnage allowed under the London Treaty, since
only three submarines were ordered annually compared to the four to five
possible on the Treaty quota. The result was that even after being reduced
to 52,700 tons the British submarine force would still contain several
boats. An factor the over-age . additional was refusal of the French and the Italians to ratify London aty, which made any decisions on scrapping
dependent, 'on a number of factors which cannot be determined at the
decision is likely present time and no final in the near future. 134- if
'. 3' were not scrapped, then any decision on her future use was reserved
for the forthcoming conference on submarine minelayer development.
prior to this meeting the 1930 submarine building programme came
under review. There were already one 'G' and two IS, class boats on order
but as these were considered experimental it was not intended to order
32. Dunbar-Nasmith to Admiralty, 14 May 1930, ADM 1/9526, 548/S. 97A, 'Future of H. M. Submarine "1I. 3'ß. t
33. D. of P. to Admiralty, 20 May 1930, ADM 1/9326.
S4. Ibid. . -. Tw' .. _..
- 170 -
further IG' class for the moment. Neither was it considered that add- itional 'R' class patrol submarines should be ordered,
'since the possibility of having to take over the two Australian "0"'s might arise if the Australian Authorities found they could not maintain them, ' therefore: 'After hearing details of certain improvements and alterations in the arrangements for mine-dropping from submarines, the possibility of including a minelaying submarine in the 1930 programme was r considered. ''ýJ
On cost it was accepted that if three small submarines ('S' class) were
ordered then three larger submarines would have to be ordered the follow-
ing year. Therefore the decision was to include one minelayer instead of
an extra 'S' class boat. The decision was conditioned on the fact that,
'if one Minelaying submarine was laid down this. year, it should be consid-
trial, further ered as under and ... no minelaying submarines should be 56 laid down until the first had been tried out. '
Thus, when the conference on submarine minelayers opened on 26 June,
the delegates were faced with the urgent need to decide on a final design
for inclusion in the 1950 programme. The latest Requirements were based,
, on the decision that a war in the Far Bast should govern our defence
measures, ' and that: 'The submarines would operate from Hong Kong. '37
This base' ryas at least 1,500 miles from the furthest port likely to need
to be mined and it was calculated that six submarines, each carrying 40
mines, would be needed to mine the 22 ports specified. Fewer submarines
of greater mine-carrying capacity were rejected since this was considered
35. First Sea Lord, Admiral Madden, 13 June 1930, ADM 138/722, N. M. M., ' Submarine Building Programme. '
36. Ibid.
37. Naval Staff, 1930, ADM 158/722, N. M. M., 'Proposed Staff Requirements for Minelaying Submarines. ' - 171 -
to prevent close adherence to the overall minelaying plan. The use of
smaller submarines was also rejected in this case, because such a policy
was regardea as an uneconomical use of the limited. submarine tonnage
available. However, this did not mean that the Naval Staff considered
40 mines per boat as the ideal number since six submarines, 'would be hard pressed to carry out the war plan, especially over a long period, and
it would be advantageous if the submarine could carry a few more mines, providing this entailed no sacrifice of other qualities. t38 On displace- ment, the limit of 2,000 tons was very much in mind but it was, 'considered
that a submarine considerably smaller than this would fulfil the require- meats. '39 One proposal was for a design of an external minelayer of only
1,490 tons (standard), capable of carrying 50 mines. Internal minelayer
designs of 1,500 tons were also presented along with others based on
existing patrol submarines.
Official policy required the final design to possess the capability
to pursue a monthly patrol cycle, allowing two to three weeks in the
operational area, and the offensive power to operate in the anti-warship
role. This implied acceptance of the need, due to limited numbers, to
develop all future submarines with a degree of general-purpose ability.
The position was reflected in the statement that:
'One of the most important requirements in a war with Japan will be the obtaining of news the limited of enemy vessels ... In view of very number of submarines we shall possess, it would be most uneconomical if submarines which are employed in operations off the enemy's coast to were unable report news of enemy movements ...
38. Ibid.
39 dDM 138/722, . 'Staff Requirements for j,Iinelaying Submarines. ' (See Note 37. ) - 172 -
'It is therefore necessary for the minelayer submarine to be equipped with a W/T instal- lation of equal capacity to that of a patrol submarine. 14=0
On the future of 11,1.31 the decision was to place this submarine in the
Material Reserve because, Ishe is a good minelayer but a bad submarine 41 and would therefore be unlikely to survive long in war. ' Others wished. to go further and pressed for 11.31 to be scrapped so as to allow tonnage to 3' be allocated to patrol submarines. '1M. ,' on account of her bad. diving qualities, is of no value as a unit of the fleet unless a large sum of money is spent on her. '42 Cost proved to be the fatal factor and resulted in '1.i. 3' being placed on the disposal list. In 1932 the submarine was sold for scrap.
Meanwhile, design work continued on the new submarine minelayer, 1ri.-fh the 'R' class design being used as the basis. In order to provide for the increase in weight caused by the mines and associated machinery it was fouth necessary to reduce the weight and power of the engines. This led to a reduction in speed from 17z to 15 knots although endurance remained unchanged on 10,000 miles at 8 knots. No alteration was expected in underwater speed but the stern tubes were omitted along with the 4.7 inch deck gun. In keeping with the Naval Staff request, the Yßi/T was to be retained as was the Asdic. Diving depth was set at 300 feet which was considered adequate by the Staff. The original intention had been to ' produce three designs, with one being an external minelayer and the
40. fDM 138/722, 'Staff Requirements for Minelaying Submarines. ' (See Note 37. )
41. Third Sea Lord, Rear-Admiral Backhouse, July 1930, Submarine Archives H. M. S. 'Dolphin', £L932/15, 'Disposal of "15.3". '
42. Dunbar-Nasmith to Admiralty, 28 Aug. 1930, Submarine Archives H. M. S. 'Dolphin', £L929/1.2,927/S. 96, 'Scrapping of Submarines in Accordance with London Naval Treaty. '
45. See Appendix: E(7). -173-
ti, e other two internal. The essential difference between/two systems was that in the former,
'the space required for the stowage and inspection of the mines is wholly outside the pressure hull buoyancy. In the internal type the stowage space, the discharge tubes, etc., must be provided for within the pressure hull buoyancy, and although 40 mines displace only 50 tons of water, yet when stowed inside the submarine, they, with their necessary gear, require a space corresponding to about 500 tons. '`'
The external minelayer was to be capable of carrying 50 mines stowed on a single line of rails. ' at the middle line of the sifomarine, with the rails extending for about three quarters of the length of the boat. The rails passed under the conning tower and as a result the conning tower and peris- copes had to be placed off the middle line. In the internal minelayer, the mine stowage and discharge arrangements were based on the 1914-18
German designs. This meant that the mines were stowed and discharged horizontally through two tubes, each carrying three mines. The system was favoured by the D. N. C. largely because the arrangement was known to have been used by the Germans with some success.
11.4.5' had not only proved invaluable in providing information on the stowage and systematic laying of mines from a submarine but had also shown the unique problem experienced by such boats in diving compared to patrol, fleet or cruiser submarines. Originally in the Admiralty's view, 'an excellent diving boat, ' when designed as a monitor submarine, the:
the behaviour 'Reports ... received on of "P1.3" as a minelaying submarine, ' 45 indicated, 'that her diving qualities, ' were, 'poor and erratic. '
44. D. N. C., 9 Sept. 1930, ADM 1/9512.
45. Submarine Archives H. M. S. 'Dolphin', 'London (See ) Treaty - Submarine Scrapping. ' Note 42. - 174 -
Investigations pointed to the conclusion that the change was due mainly to three reasons.
-'(a) The position, both vertically and long- itudinally, of the buoyancy of the mines themselves. This is such as to cause the stern of the submarine to sink rapidly initially, thus making it difficult to submerge the bow and utilise the hydroplanes. The amount of this buoyancy and its longitudinal position also vary vdth the number of mines on board. '(b) The size, and to some degree the shape, of the superstructure casing in which the mines are stowed. '(c) The large increase in the overall submerged displacement due to the water carried in the super- structure casing, without a corresponding increase in hydroplane area. '`
It was decided that these problems could be solved in the external mine- layer design by providing a pressure-tight bow buoyancy tank of sufficient capacity to ensure, 'that the vessel will dive by the bow whatever the number of mines on board. '47 Improvements were also to be made to the superstructure to improve the rough weather ability of the submarine and the after hydroplanes were to be re-positioned in an attempt to rectify the diving problems arising from the increase in submerged displacement.
'M. 3' as a minelayer had an abnormal free-flooding capacity due to the large superstructure casing. The new design was still calculated to have twice the capacity of the 'R' class but not greatly different to 'X. l' or 'K. 261,48 both of which were regarded by D. N. C. as tgood diving boats. '
The internal minelayer designs allowed only 830/loof the buoyancy,
'in which to install the other features of the design, and these must therefore be inferior to those of the external type. '49 Moreover, it
46. ADM 1/9312, D. N. C. (See Note 44. )
47. ADDS1/9312, D. N. C. (See Note 44. )
48. See Appendix: E(8).
49. ADMS1/9312) D. N. C. (See Note 44. ) . - 175 -
was considered that only two features, length and power of the diesels and the size of the battery and motors, could be substantially modified.
Nevertheless, the internal minelayer was not expected to have greatly inferior diving qualities compared to the 'R' class design on which it was based. The major facts in reaching a decision were: 'This, ' diving quality, 'with a better inspection of the mines and an appreciably smaller silhouette when on the surface, are the main advantages of the internal type. In'other respects the external minelayer has outstanding advan- tages. '50, A decision on the final selection of the most suitable design was left to a conference called for the 29 September. D. IT. C. and Rear-
Admiral"(S)'were firmly in favour of the 'external' design and supported by the Controller; it was decided to recommend this type for inclusion in 51 the 1930 progrämme. A major factor in this decision was the ability to meet the Naval Staff Requirements. Experiments with had shown that mines could be stowed on board for the minimum period of one month and that propulsion and machinery were up to standard.
Once the decision had been-reached on a final design the hope was that approval would be granted by the Board the following month52 and. that specifications could be ready by March 1951.55 Then, pending the results of the London Naval Conference, a decision would probably be made on whether or not to implement the suspended 1929 and 1950 programmes. If the decision was favourable it was hoped to place the initial order in
50. ADM 1/9312, D. N. C. (See Note 44. )
51. Backhouse, 30 Sept. 1930, ADM 1/9312, 'Conference on Irevr Submarine Minelayer. ' (Attended by A. C. N. S., R. A. (S), D. I1. C., D. IF. E. (S), D. N. O., D. T. L4., E. in C., D. E. E. )
52. Board of Admiralty, 2 Oct. 1930, ADIS 1/9312.
53. Board Minute No. 2805,5 Mar. 1931, ADM 167/87, 'Design Approval H. M. S. "Porpoise" 1930 Submarine Minelayer. ' PAGE
NUMBERING
AS ORIGINAL - 177 -
Two hundred tons, although small when taken out of context, was made extremely significant by the London Naval Treaty. Nevertheless, it was considered that, 'if the increase can be regarded as final for the class and would materially increase efficiency, it might be acceptable. '57
This attitude highlights the problems which tended to stem from limitation agreements, with the overall numbers affected and leading to artificial conclusions being drawn as to strategic requirements While suppressing the number of models under development in favour of production of the maximum number of hulls permissible. Support was provided by those,
'opposed to exploiting of "surplus" treaty tonnage in the way proposed by
D. of T. D., '58 opinion being that total numbers were more important.
Successful efforts were made by D. N. C. to counter the attitudes against increasing displacement, in the case of the 'Porpoise' class, as well as satisfying those who wished to be reassured that the changes prop- osed would increase the fighting efficiency of these submarines. During may 1953 it was pointed out that sea experience with H. I.I. S. 'Porpoise' had shorm that the stability of this boat in a state of loin buoyancy was unacceptable for future submarines of this class. However, an increase in displacement was expected to provide the solution. The view was now that, allied to the other advantages already proposed, the new develop- ment justified the increase in displacement. Endorsement was provided at a conference on 12 June, attended by the First Sea Lord, Controller, and Deputy and. Assistant Chiefs of the Naval Staff.
One other design alteration, considered and approved by this confer- ence, concerned the carrying of oil fuel within the pressure hull of
57. D., of P., 22 Mar. 1933, ADM 1/9552, M. F. 0.786/53,4.
58. D. C. N. S., Vice-Admiral C. J. C. Little to Third Sea Lord, Rear-Admiral C. M. Forbes, 20 Apr. 1933, ADM 1/9352, M. F. O. 786/53. - 176 -
June 1931, since the last three 'L' class converted minelayers were about to reach scrapping age and this gave some urgency to the subsequent action: all target dates being achieved despite the continuing climate of retrench- ment and disarmament. Unlike the case of the cruiser submarine there was a real requirement and unlike the fleet model the project was technically feasible and achievable. The first of the 'Porpoise' class54 minelayers,
H. M. S. 'Porpoise', was launched on 30 August 1932, twelve years after the initial Naval Staff Requirements were set out.
Following fitting out, 'Porpoise' underwent extensive minelaying trials during May, June, and October 1935, laying up to 50 mines until 55 there was final satisfaction with the submarine's progress.
Prior to the authorisation of any further boats of this type it had been considered necessary to examine the design implications of several general decisions.
D. N. C. was hopeful of an early favourable decision, which would allow work to begin on the next 'Porpoise' class submarine (tGrampus') by June
1954. Although the D. of T. M. and the D. S. D. concurred, there was a less enthusiastic response from other quarters. Talbot, when D. N. E., had been concerned about the increase in tonnage generally, caused by the adoption
of the suggested proposals which he felt would not add much to the fighting
efficiency of these submarines.
'As regards submarine new construction in general between 1929 and 1952 inclusive, the total original standard displacement of 12,895 tons will be increased by 210 tons, if the proposed increase of "Porpoise" class is included. This increase is equivalent to approximately one third of the Standard displacement of one Swordfish" class submarine. '56
54. See Appendix: D(29).
55. D. T. M. 19 Dec. 1953, ADM 158/752, N. M. M. ,
56. D. N. C., 16 Feb. 1955, ADM 1/9552, II. F. 0.786/33,1. PAGE MISSING IN ORIGINAL - 178 -
future 'Porpoise' class submarines. In the case of H. M. S. 'Grampus' the whole of the tank space available within the pressure hull was already required for trimming and compensating water for diving the boat, compen- sation for mines, fresh water and lubricating oil. In order to include the oil fuel it was necessary to lengthen'the pressure hull. Approval having been given to the principle of post-design increases in displace- ment, this could logically only lead to agreement to the oil fuel storage scheme. These proposals were put before the Board along with a proposal to transfer 'Grampus' to the 1935 programme and delay construction until
March'1934. This was to allow time to complete design changes, such as 59 oil fuel storage. The final design retained a4 inch gun, allowed an increase of oil fuel to 116 tons and included the after external main tanks being fitted as reserve oil tanks. This ensured a reduction of only 1,500 miles endurance from the original design as against the expected 3,500 60 miles and allowed a radius of 10,000 miles at 8 knots.
Another three submarines of this class, built to the revised 'Grampus' designs were ordered under the 1934,1935, and 1956 programmes. The mine- laying gear in"all these boats gras based on the chain conveyor system fitted at the stern below the main rails which were laid externally along the pressure hull, and enclosed by a high casing extending the entire length of the hull, except in 'Porpoise'. The mine laid was the standard
Mark XVI.
On the outbreak of war, in September 1939, it was intended to supple- ment these submarines by converting some of the new 'T' class boats to lay
59. Board. Minute No. 3086,22 June 1933, ADM 1/9552, M. F. 0.786/35.
60. Secretary to Board, 31 Oct. 1955, AD 1 9552, M. F. 0.786/33, 'Memorandum on Sketch Design for Minelaying Submarines of the 1953 Programme. ' - 179 -
mines from vertical tubes fitted in their external ballast tanks. However,
trials indicated that. the fitting of mine tubes in the external tanks
reduced the speed of these submarines by 12 knots. In addition, diffic-
ulties were encountered with the release mechanism of the mines and also
water noises caused by the mine tubes interfered with the submarine's
Asdic. It had been intended to order three more 'Porpoise' class boats
under the 1940 Emergency War Programme but by 1940 the design of the
Mark II ground magnetic mine, intended to be discharged from the subma-
internal rine's torpedo tubes, had been finalised. As a result it was
decided not only to abandon the existing schemes for submarines mine- laying, halting conversions of the 'T' class and causing the cancellation
the further three of 'Porpoise' class boats, but also plans to design a
class of five new submarine minelayers based on the 'S' class design, 61 larger although and heavier. These had been intended as a combined patrol/minelayer submarine carrying twelve Vickers Type T Mark III mines in free-flooding tanks and capable of laying -these mines submerged in depths 62 up to twelve fathoms.
Later it was discovered that the Mark II mines were ineffective if laid. deeper than ten fathoms and not until 1944 were a number of these 63 mines laid successfully by submarine, in the Far East.
The original requirement for a submarine minelayer was essentially
tactical sound and met a need. The question mark against such a concept
the was and remained whether limited number of mines which could be carried
61. See Appendix: E(9).
62. D. N. C. to Third Sea Lord, Rear-Admiral B. A. Frazer, ADA 199/1924, 'Proposed 1939 Patrol/Minelayig Submarine. '
65. Admiralty, 1945, ADS 1997±924, 'State of the Submarine Service, 1939/45 - ?lining. ' - 180 =
would ever constitute more than a nuisance value. Clearly only submarines
could lay mines close to enemy ports but minesweeping forces were able to
clear small fields fairly easily. Nevertheless, this required the enemy permanently to assign extra minesweeper forces to these areas. Such was
the situation at the close of the First World War. Over the next decade
and a half a slow but regular effort was undertaken to produce an efficient
specialist minelayer submarine capable of carrying standard mines. In this respect the Admiralty design teams proved effective but other technology kept pace with them and finally outstripped them in the form of minelaying by aircraft. These could undertake the close inshore minelaying previously reserved for submarines far easier, more quickly and much more economically.
In addition, the design of fast surface minelayers meant that large mine- fields could be laid under cover of darkness, so that the correct decision was taken not to expand the 'Porpoise' class beyond the six ordered.
Finally, with the design of mines capable of being laid through submarine
torpedo tubes it was recognised that the requirement for the specialist
submarine was over. The limitation on shipbuilding facilities caused. by
the neglect of the inter-war period also meant that priority had to be
accorded to those categories of warships most vital to the immediate needs
of the Second World War and in 1939-40 this meant the patrol model in the
submarine category. - 181 -
CONO JSTON
The problem of providing sufficient numbers of submarines to make an effective contribution to British naval strategy properly belongs to the realm of policy. However the effect infiltrated the practical problems of development throughout the period. The symptom was a greater constraint on the amount of resources allocated for submarine construction and develop- 1 ment than viere applied to any other category of warship. Successive naval disarmament conferences had first threatened the complete abolition of the submarine and later brought about tonnage limitation agreements.
Either abolition or limitation would hopefully bring financial savings and this theme, coupled to an awareness of the destructive power of the subma- rine in the hands of an enemy, dominated the initial attitude of the
British Government and Admiralty to submarine development.
In the immediate post-1918 period, the Royal Navy possessed a variety
of different submarine models. It is understandable that the pressures of war produced such a diversity of types but a simple explanation does not
exist for the prevalence of experiments which persisted between 1918 and
1939. The situation is even more difficult to understand against the background of economic stringency and arms limitation pressures. The
steady reduction of submarine tonnage, because of the attempts to get
international controls, resulted in fewer submarines to cover many oper-
ational requirements. This precluded extensive improvements to all subma-
rine types and. finally development was concentrated on the patrol submarine, which was capable of undertaking the majority of roles, such as reconn-
aissance and anti-warship attacks. Nevertheless, it was not until 1923
1. See Appendices: C&B, for comparison of annual naval estimates and yearly submarine construction figures. - 182 -
that the first post-war designs - '0' class - were sanctioned as part of a limited development programme. This in turn was only a small section 2 of the overall construction programme for the Royal Navy, authorised. as much to alleviate the severe unemployment in the traditional heavy industries such as shipbuilding and steel making, as for any specific strategic purpose.
The struggle by the Submarine Service for resources within the Navy was at another level typical of the situation facing the Admiralty in relation to the public budget as a whole. The Admiralty waged a rearguard action through the twenties against the pressuret by successive Governments to. reduce defence r xcpenditure. The acceleration of defence cuts, which culminated in the tonnage quotas agreed to at the 1950 London Naval Confer- ence, were both cause and effect in a collapse of morale and reflected the indifferent leadership within the Admiralty after Admiral Beatty's retire- ment. Nevertheless, following the failure of the 1955 London Naval
Conference the Admiralty reiterated that there would be a- decline in the absolute as well as the relative strength of the entire Royal Navy unless
Britain followed the other naval Powers and undertook extensive new construction. However, long years of neglect meant that British ship- building capacity,. especially in submarines, could not be rapidly regen- erate. d; time and massive financial aid were essential for success. No means of control existed over the former factor but the real threat of foreign aggression gradually secured the release of constructional resources.
The weakness-of the Royal Navy's submarine force, in September 1939, was primarily in numbers available. How far economic stringency was an excuse rather than an explanation is not clear but there was no doubt about
(See 2. JiDM 1 8702`151. Chap. 7, Note 16. ) Out of a programme of £23.3 million provision was made for only three submarines. - 185 -
the failure to provide an adequate number of hulls. Seventy eight
British submarines were lost during the Second World War, 21 more than
the number available at the outbreak of war. The shortage was to be
critical early on and the persistent attention to disarmament or arms
control policies must bear much of the responsibility. Despite these financial, political, and tactical shortcomings of support for the
submarine, the question of technological development was not ignored.
Advances were not regular or spectacular and the development of such
specialist submarines as the fleet and cruiser models was to prove
unsuccessful. Nevertheless, progress was made and the Royal Navy came
to possess three sound designs (QS', 'T' and 'U' classes) which success-
fully formed the mainstay of British submarine strength during the Second
World War. Although surface and submerged speeds remained largely unchanged
from 1918 the boats in service in 1939 were more strongly built, could
dive deeper, possessed greater endurance, and a larger torpedo armament
(though not much more advanced torpedoes), as well as new auxiliary equip-
ment such as Asdic and longer-range W/T.
The importance of these technological developments was not Tost on
the Royal Navy but the period was dominated by a constant stringency which
spread the 'jam' - in money and in research and development terms - very
thinly. Submariners had to compete not only in a choice between submarine
options but also with the need to improve surface warships, in the face
of increases in the strength of the other major surface navies. Despite
the relegation of the submarine to a subsidiary role, the fact that it
continued to received what attention it did after 1918 was a refl66tion
of its success as a threat as much as it was a reflection of the perceived
need for a British submarine force. Thus the technical problems faced and
sometimes overcome during this period were linked with the more complex
national and international political factors which overshadowed the two - 184 -
decades of peace between the fforld Wars. The political need for financial stringency influenced the pressure for reduction of defence forces and expenditure. This resulted in greater financial influence over decisions rather than adherence to any criterion of military requirements. The specific political problems faced by the Submarine Service during the inter-war years were to reflect to a serious degree the overall difficulties facing the Royal Navy during this period as one disarmament conference succeeded another. Only when this policy was played out was the British submarine force then able to turn from the struggle to survive to the struggle to provide an adequate contribution to the general functions of the Fleet.
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