no G CRAFT & HYDROFO

THE INTERNATIONAL REVIEW OF AIR CUSHION AND e're on ops no b'IW THE WORLD'S FIRST FULL Y-OPERATIONAL SQUADRON

BHC hovercraft have now BHC hovercraft lead the world. BHC hovercraft are the only joined the forces - as regulars Incorporating systems and hovercraft that have been used on enlisted for active service, at components proven in over 20,000 military operations - both by British home and abroad, with the hours of operation all over the Defence Forces and by the U.S. Royal Corps of world, the 10-ton SR.N6 carries 30 . They have proved themselves in extremes of climatic conditions,, Hovercraft Squadron. This fully-equipped troops or over 3 tons of freight, and is able to from tropical jungles and deserts vital decision by the British mount the latest weapons systems. to the frozen arctic - from Sweden Government to purchase BHC It cruises at 56 knots and is to Sarawak, from Thailand to the SR.NG's for the world's first unrestricted by reefs, sandbanks, far north of Canada. fully-operational hovercraft underwater defences, ice, tide BH C strength is further emphasised squadron, marks the full state or shallows, giving military by the recent Government decision establishment of hovercraft as forces a freedom and speed of to order the larger 40-ton BH.7 in front-line vehicles with a vital movement by day or night far in both the patrol version and role in military operations and advance of anything feasible for the logistics support version. will undoubtedly influence conventional craft. The 10-ton SR.N6 is in full production with the 40-ton BH.7 defence planning throughout to follow shortly. the world.

BRITISH HOVERCRAFT-WORLD LEADERS IN THE HOVER TRANSPORT REVOLUTION I

4 1966 WrrruNo *mcR*n rlMtrsn SAdHOEOS ROE DIVISION

Ebritish hovercra t corporation limited VEOVlb MARCH1967 Vor. 6, No 6

Editor : JUANITA KALERGHI HOVERING CRAFT AND is produced by Kaierglzi Publicatio~zs, 50-52 Blandford Stveet, London, WI. Telephone WELbeck 8678. Pvinted in Great Britain by Villiers Publications, London, NW5. Annual subscrip- tion: Five Guineas UK and equivalent overseas. USA and Carzada $15. There are twelve issues annually. Contents of this issue are the copyright of Kalerglli HOVEMNC CRAFT Publications. Perniission to reproduce pictures and text can be granted only under written agreement. Extracts & HYDROFOIL or coniments may be made with due acknowledgemenf to Hoveving Craft nnd Hydrofoil. FOUNDED OCTOBER 1961 ADVERTISING REPRESENTATIVE L. Ternple Rosswiclc Ltd, 3 Queens Court, Queensway, London, W2. Telephone BAYs~vatev5812 First Hovering Craft & Hydrufoil Monthly in the World

RITISH HOVERCRAFT CORPORATION are no longer the sole and water-screw propulsion will be incorporated. B possessors of a licence to manufacture hovercraft in There will be savings, too, in personnel. Training pilots Britain. Eighteen months after it started in business, for amphibious craft is an expensive business, Hover- Hovermarine Ltd has been given the go-ahead by Hover- marine's sidewall craft will be handled by marine skippers. craft Development Ltd to start production of sidewall The first Hovermarine craft is, after all, basically a marine craft in this country. The company will be unable, under conception. The lift engine and fan system are started up its licence, to touch flexible skirts, which remain the virtual and run at a fixed duty like the electrical generator system monopoly of BHC. But, late and limited. though it is, of a boat. the grant of Hovermarine's licence deserves an uninhibited Sideways drift will not be the problem it is to amphi- welcome. bious hovercraft in crosswinds. That is because of the HDL may seem open to criticism on the ground that it immersed keels. Nevertheless the new craft may eventually is preventing competition between manufacturers of have a certain amount of amphibious capability. It is similar types of craft. But it is encouraging healthy rivalry hoped that, at a later stage, the craft will be able to climb between the two main lines of hovercraft development. slipways. Indeed Hovermarine have already filed patents We can now settle down to watch a fascinating wall versus for necessary adaptations. skirt contest whose outcome will be pure gain to the industry as a whole, whatever the effects on the contenders. Three or four operators have already approached One possible result, perhaps the most likely one, is that Hovermarine for its new craft. Between Grimsby and Hull the Humber offers an obvious route. On the military each type will be found to have its advantages for different operations. Certainly this is what Hovermarine appear to side, Hovermarine will try to persuade buyers of the value envisage. As against the obvious drawback that their craft of their craft as carriers and fast patrol craft. will not be amphibious, they point out that for the opera- The possibilities are wide. tors who wish to reduce their financial risk, the first of Our final commendation should go to the City commo- their projected craft will be a 68-seater costing only about dity brokers C. Czarnikow Ltd who have given Hover- £60,000, whilst a 38-seater SR.N6 costs £120,000, Main- marine major financial backing. It is good to see a young tenance and running costs are correspondingly less since and enthusiastic team backed by experienced men in the normal marine components - marine diesels, for example, City.

The Hovercraft Pioneers 4 The First Air-Stabilised Suprarnar Hydrofoil Built by Westerrnoen Shipyard 15 People and Projects 7 f he World's Largest Hovereraft 20 The Application of Hovereraft 12 The History of Hydrofoils 28

COVER PICTURE : The first air-stabilised, 65-tort passenger hydrofoil craft. (See article on page 15) Bryan Coo

INthe short time that hovercraft have been in existence, they have not only introduced an entirely new concept in transportation but they now represent a thriving industry in their own right. It is only ten years since the first company, Hovercraft Limited, was formed by Christopher Cockerel1 in 1957 for the purpose of promoting his revolutionary idea. And yet in this period of time there have been significant advances. A number of different companies in the aviation and shipbuilding industries have worked on design studies and experimented with various prototypes. Regular passenger-carrying services have been inaugurated. Craft have been tested under many operational conditions - over snow and ice, desert and jungle, in calm inland waters and rough seas. Orders are now mounting for production craft, and the military use of hovercraft has been proved in Borneo and Viet- nam. Britain has the world's first fully-operational hovercraft squadron. The first hover- craft races have been held, in Australia and England. To the general public, hovercraft are no longer a one-day-wonder but have become such an accepted fact of life that a popular national newspaper can successfully run a "do-it-yourself hovercraft" promotion campaign. All this in ten years. And events continue to progress so rapidly that it is some- times difficult to remember just how short a time ago it was that the first hovercraft were built. As with the development of any new idea, it was mainly due to the drive and imagina- tion of a few pioneers in the early days that made hovercraft possible. Designers, engineers, test-pilots, financiers and civil servants all played their part at a time when there were many in responsible positions who said the idea was impractical and would not work. The leading pioneer was, of course, Christopher Cockerel1 himself, but there were others who had to make the concept a reality. It is these men, the pioneers of a new industry, who are the subject of this series of articles. First come the test-pilots, the forerunners of a new profession of hovercraft pilots who are today known as Hover-Commanders. They are now mainly concerned with training new pilots to meet the increasing demand from ferry operators and military services. But a few years ago, it was they themselves who sat at the controls of new hovercraft prototypes and, starting from scratch, developed techniques for piloting them. Three men in particular have pioneered work in this field - Leslie Colquhoun, Peter Lamb, and Peter Ayles. The subject of this first profile is Leslie Colquhoun. In July 1962 the world's first commercial hovercraft ser- vice was operated between the towns of Rhyl and Wallasey. Over a period of eight weeks, nearly 4,000 -paying pas- sengers were carried in the VA-3 craft built by Vickers- Armstrongs (Engineers) Limited. The chief pilot on this service, and also Hovercraft Operations Manager for Vickers, was Leslie Colquhoun. He thus became the first man to pilot a regular passenger-carrying hovercraft. Today, Leslie Colquhoun has moved on from the chal- lenge of test-flying to a new challenge in the world of business. At the age of forty-six, he is Managing Director of , a British-registered operating company set up jointly by Swedish Lloyd and Swedish American, and from an office in he is organising the cross- Channel hovercraft ferry service which Hoverlloyd first pioneered last year. But he is still concerned with the practical business of piloting hovercraft as an instructor of new pilots for this service. "We took a tremendous risk," says Colquhoun as he recalls the days of that first commercial service by Vickers. "It hadn't been done before, and we weren't even sure that the craft would stand up to it." In fact, there were break- downs, although most of these were repaired by engineers working all through the night so that the public was hardly aware they had occurred. And there was one occasion when the engines failed while the craft was out at sea and it had to be ignominiously towed ashore. Luckily, there were no passengers aboard at the time, for, as Colquhoun says, an accident of that sort or worse could have been a big setback to the public acceptance of hovercraft. "Handling a hovercraft is like driving on an icy road," says Colquhoun. "Directional control is the biggist prob- lem, and it takes a lot of experience and concentration to drive over water without sideways movements or skidding. %he biggest mistake that new pilots under training make is over-violence with the rudder, when they realise how quickly yaw and skid can be produced." Leslie Colquhoula Most, but not all, of the men Colquhoun is training have been pilots, but he considers that a knowledge of standard seamanship is highly important. So much of the the effective hoverheight to up to 2 ft. During 1962 and work of piloting a hovercraft requires an understanding of 1963 he took the VA-2 on demonstration trials to Ger- wave motion and of knowing the best conditions in which many, Holland, Sweden, Denmark and Libya. It was to turn. probably this craft, more than any other, which did most to demonstrate the idea of hovercraft overseas. In 1964 he "Turning downwind is difficult, and that's when you can spent several months in the United Statcs with the VA-3, get trouble," he says. "Slow-speed handling can also be a for which Vickers had a licence agreement with Republic problem. You can get into situations when it's like stalling Aviation, and he believes it was largely due to demonstra- in an aeroplane." tions of this craft that led to the keen interest now being Although Colquhoun has trained men in the United shown by the American military authorities. States to pilot a hovercraft in eight hours, he considers On returning to Britain, he found that Vickers were that it takes between SO to 100 hours for a man to become reconsidering their whole association with hoverc'raft and really competent. His own experience in piloting hover- very little development work was being done. craft goes back to the days when Vickers-Armstrongs first became interested in the craft. At the time, he was a test- "It was a great pity," he says. 'Tickers had lots of pilot at South Marston, responsible for fighter production ideas, not only for skirts but for wheeled vehicles and testing. But in 1959, when production orders for a number various load-carrying devices." of were cut, the company looked into the possi- Nevertheless, the company decided not to support further bilities of hovercraft and in fact became the second com- development on hovercraft, and Colquhoun left in Decem- pany to join the "Hovercraft Club", after Saunders-Roe. ber 1965 to become Operations Manager of Hoverlloyd. In 1960, Colquhoun became Operations Manager of the He was responsible for setting up the organisation for the newly-formed Hovercraft Division and worked on all the cross-Channel service which in 1966 carried some 10,000 early Vickers craft. He was closely concerned with the passengers, using an SR.N6 craft. Me was appointed Vickers development on skirts, particularly the first con- Managing Director of Hovermarine at the end of that voluted skirts fitted to the VA-2 in 1963, which increased year. Before becoming concerned with hovercraft, Leslie Vickers' chief test-pilot, with responsibility for all produc- Colquhoun had spent his whole career as a pilot, first with tion test flying of the sweptback wing Swift. When the the Royal Air Force and then, after the war, as a test- order for this aircraft was cancelled in 1957, he went to pilot for Vickers-Armstrongs He was nineteen when he South Marston as head of fighter production testing, work- joined the RAF in 1940 and became a photo reconnais- ing mostly on the Scimitar. Further cuts in aircraft orders sance pilot, flying Spitfires. In 1942 he was posted to Malta, were made, and then came the various mergers within the then holding the rank of sergeant-pilot, and was awarded aircraft industry, with Vickers-Armstrongs joining with the Distinguished Flying Medal for his work during the English Electric and Bristol Aircraft. It was in 1959 that siege of the island. At one time he was one of only two Vickers began to look into the possibilities of hovercraft pilots flying reconnaissance missions from Malta, covering and the following year Colquhoun was given the key job in particular the enemy build-up in Sicily. He was com- as Operations Manager. missioned and later, in 1943, as a flight lieutenant, he was Leslie Colquhoun now lives in Broadstairs with his wife, attached to a US Air Group in Italy. He was awarded the Kathleen, and four daughters, of whom the two eldest are Distinguished Flying Cross for his nnjssions in this area of twins. He is a quiet, unassuming man who nevertheless has combat. a determined belief in hovercraft. One of the reasons he In February 1945 he was seconded to Vickers-Arm- took his present job is that "it is a tremendous challenge strongs as a fighter test-pilot, but it was not until April of to demonstrate that there 1s a future for hovercraft". Much the following year that he finally left the RAF. He produc- of the opposition Colquhoun now finds is directed from tion tested a number of aircraft, including the Seafang and other ferry operators, who see hovercraft as a threat to the later Spitfires, and then came the Attacker, the first jet existing shipping services. fighter designed by Vickers. It was during a test flight in the first production model in the spring of 1950 that, while The Author flying low over the airfield, part of the wing collapsed. He Bryan Cooper is now a freelance author and screen- would have been well justified in using the ejector seat - writer, hut while he was working as ar public relations it would in fact have made him the first pilot to use such cpficer with British Petroleurn until 1965 he wax one of the a device. But he decided instead to try to save the aircraft. first to be~omeinvolved with hovercraft in their early i He managed to land at a speed of some 200 mph and days. "BP was the grand patron of the industry, handing handled the controls so well that the only damage caused out free fuel and products," he recalls. was a burnt tyre. It was therefore possible for the de- He is co-author with Dr Tom Gaskell of a successful signers to examine the aircraft and discover where the book, North Sea Oil - The Great Gamble, published lasf fault lay. For this exploit, Colquhoun was awarded the year by Heine~l~ann,and has written scripts for such well- George Medal. known television series as "The Troubleshooters" and "No After this came development tcsting of other aircraft, Hiding Place", as well a& documentary films, and plays for such as the 510 and the amphibious, variable instance wing BBC radio. He is at present working on a bolok on the Seagull. Then in 1954 he became deputy to Mike Lithgow, First World War.

ppp ------

LILY BRAND Pieter Schoen & Zoon Lfd, MARINE PAINTS

Stocks and agents all over the world Hovercraft Ltd have ordered a 165-ton The Israeli Government has approved plans for the pro- SR.N4 passenger/ ferry from the British Hovercraft duction of air cushion vehicles in Israel. Power units and Corporation. It will be delivered in the spring of 1968. other accessories are likely to be imported from Britain. An order for two SR.N4s was placed in June 1965 by The chief designer of the craft and director of the Hoverlloyd, a British-registered operating company set up company, Israel-American Motor Corporation, is Mr N. jointly by Swedish Lloyd Steamship Company and Swedish- Kripitznikoff. American Line. The first will be delivered early in 1968 A working prototype has already been tested success- and the second early in 1969. They will be used in a cross- fully, and a finished prototype is now in hand. The craft Channel service between Rarnsgate and due to start is a six-seater designed for use on inland waters, and will in May 1968. sell at $16,200 ex factory. It has a n~aximumspeed of Four SR.N4s are now under construction at the main 52 knots and a range of 155 miles, and can be used as a BHC plant at , . The first two are food transporter, ambulance service, mail , or for already in final assembly and manufacturer's trials are the transportation of passengers. Commercial production scheduled to begin this September. is to start within fifteen months. * * * * * -k-

The Soviet: Central Hydrofoil Design Institute is now Junior seamen of the are a two- working on new motor of the Qka type. Two types seater "Hoverhawk" at the training establishment Ganges of these boats will be put out: with hydrofoils and without near Ipswich. The craft is 10 ft long, 8 ft wide, and powered them. by second-hand motor-cycle engines. With four passengers on board, this boat, which is If the craft is ready on time they plan to enter it in the equipped with either one Vikhr or two Moskva outboard first official National Hovercraft Championships to be held motors, will be able to develop a speed of up to 30 rnph at Apethorpe, Northants, on June 3rd. using hydrofoils and up to 20 mph when gliding (without foils). The boat hull is 4.2 m long and 1.5 m wide. It is designed for personal use by hunters, anglers and tourists. Hover-Air Ltd, of Crowland, , have shipped * * -k one of their 'Woverbats" aboard Ellerman's Wilson Zydd ; on the Kent coast may become the first Line's cargo liner Salerno. The one-passenger craft, which international hoverport. The possibility of private shipping is powered by three 250 cc engines (one for lift and two companies co-operating with British and French railways for propulsion) and can over flat land surfaces or a to operate cross-Channel hovercraft services from the air- calm sea at up to 60 mph, will be demonstrated at the is being investigated. British United Airways, who Boat Show in Stockholm this month. own the field, are eager to take part. * -k *

Known as the "'Hoverboggun", th hovercraft sledge shown lzere with Mrs Angela Huwker "in control" was originally ceonstructe to avoid Reynold's number problems in the design of low- wear high eficiency cushion delivery systems. The machine is powered by a 7 bhp cultivator motor, and has a daylight clearance of approximately 2 in when loaded. Speed is dictated by the steepness of the incline traversed. The machine was designed by A. R. Hawker and J. E. Cook and built at Barnham Broom Hall, Norfolk The British Hovercraft Corporation's SR.N6 being loaded on the foredeck of the "Sylvania". The hovercraft wilE be fuelled and lubricated by BP. (See below for further details)

On Thursday, February 23rd, a British Hovercraft Corm From February 22nd to May loth, 1967, an SR.N6 poration's SR.N6 visited the River Humber to demonstrate hovercraft will be on charter to the Cunard Line. The the feasibility of regular passenger ferry operations to craft will be carried on board the RMS Sylvanie during leading industrialists and local government officials. five Mediterranean cruises which start and finish at The hovercraft followed a 16 nna route from an unpre- Gibraltar. pared base on the beach at Cleethorpes to Hull, and the The hovercraft will act as a passenger carrier at the journey time for the single trip was approximately twenty- various of call, and in addition demonstrations will two minutes. be given to potential civil and military customers during With the rapid industrial development which has recently visits to Lisbon, Malaga, Palma, Tripoli, Athens, Istanbul, taken place in North-east Lincolnshire, a pressing necd has Beirut and Gibraltar. arisen for a fast and reliable link across the River Humber. The SR.N6 carries thirty-eight passengers at a maximum Detailed investigations into local conditions by BHC indi- speed of 60-64 hots, and is powered by one Bristol cated that a hovercraft service could best meet this need. Siddeley Gnome gas turbine of 1,050 hp. The SR.N6 used on this exercise was chartered for the occasion by BHC from Hoverlloyd Ltd. * * * An idea for reducing the hydrodynamic drag of sidewall Hoverlloyd Ltd have announced that their cross-Channel curtains in hovercraft has been put forward by Jarornir hovercraft service between Ramsgate and Calais will begin Housa of Prague. He proposes that instead of the curtains its 1967 season on Saturday, April 29th. used today overlapping discs should be set along each side. There will be four scheduled return trips and extra ser- These should be free to spin by the pressure of the water vices will be run when required. remain at 45s single, as the craft moves forward, or should be driven by shafts day return 70s. For children under twelve the rates are: drawing power from propulsion machinery. single 22s 6d, day return 35s. He maintains that the free-spinning discs will quickly Hoverlloyd's two SW.N6 hovercraft, Swift and Sure. acquire a peripheral speed corresponding closely to the take approximately forty-five minutes to cross from Rams- forward speed of the craft, and he estimates that the side- gate to Calais. Each of the craft can carry thirty-six wall drag could thus be reduced from one-third to one- passengers, and special charter terms are available on sixth of its present value. If the discs are power driven, the , application for parties of twenty-four or more. drag should be reduced to almost zero. Bookings for Hoverlloyd flights can be made at Hover- Ms Housa admits that there will be some loss of cushion lloyd Ltd, The Hoverport, Ramsgate (Telephone: Thanet air in this arrangement and that extra weight is involved, 53701), and C. H. Foissey, The Hoverport, Calais (Tele- but he believes that these economic disadvantages will phone : Calais 34.38.93 and 34.55.03). diminish as the size of the hovercraft increases. * * * * * 34 Mr , CBE, talking to Mr Norman Piper, Managing Director of Hover- marine Ltd, at the Press con- ference held to announce Hover- marine's acquisition of a licence. In the background is Mr Douglas Harnmett, of British Petroleum

On 16th February, 1967, Movemarine Etd, of South- Mr G. C. J. Hodgson ampton, announced that it had been granted a licence by Mr Gerald Christopher John Hodgson, aged 45, is Hovercraft Development Ltd to develop, build and market Commercial, Production and Sales Director. A Lanca- rigid-sidewall craft. The hulls and superstructures of the strian, he was educated at Dumfries ,4cademy and Edin- first two 60-seat craft will be built in glass reinforced burgh University, and was apprenticed to Dumfries County plastic by Halrnatic Ltd, of . Council as a civil engineer. During the war he rose to the In addition to the company's standard range of diesel- rank of Captain, Royal Engineers (Field Squadron), and powered 30- and 60-seaters (to craft up to 70 tons) with served in Burma for three years. After the war he joined speeds of between 35 and 50 knots, they are developing John Holt and Co, the Liverpool shipowners, and was in the HM.4, a new concept of the sidewall principle, where charge of their technical department for West Africa. He the payload is carried in two longitudinal members com- then had a spell with the north west sales organisation of prising the sidewalls. The structure is braced by tubular Williams & Williams, metal window manufacturers, before members and the cushion retained by a flexible membrane joining Saunders-Roe to sell military engineering and cover. The craft will have a 150 ton payload, maximum bridging equipment. Later he worked with C. H. Bailey speed of 45 knots and a wave height capacity of 8 ft. Ltd in Malta and South Wales, and then became sales Also, in conjunction with Helicopter Patrol Craft Ltd, manager of Halmatic Ltd, who specialise in vessels built Hovermarine has formulated HPC-HI, a sidewall hover- of glass reinforced plastics, Mr Hodgson lives at Crow- craft to act as a mobile floating helicopter base. thorne, Berks. Hovermarine Directors are :- Mr E. G. Tattersall, BSc(Eng) Mr IV. D. Piper Technical Director is 35-year-old Edward Gunston Managing Director of Hovermarine Ltd is Norman Tattersall, who has been engaged in hovercraft design Douglas Piper, aged 46 A Tynesider, born at Blaydora, ever since they were first developed in Britain. Born in he served thirteen years in the Royal Navy, starting in the Cardiff, he was educated locally and at Loughborough Fleet Air Arm and later transferring as an officer to sub- College. After national service in the RAF, he was a post- , minesweepers and general service. After the war graduate apprentice with Saunders-Roe and later joined he was a founder member of the Navy's Clearance Diving their hydrodynamics department. He left that company in Division. He began his post-war career with the marine 1959 to join Hovercraft Development Ltd, and worked division of Turner & Newall Ltd, who specialise in non- closely with Mr Christopher Cockerell, CBE. He left HDL combustible materials for . He then joined Saunders- in 1965, as a principal hovercraft engineer, to join Hover- Roe, at Anglesey, and was concerned with the construction marine when it was formed. During his time with HDL he of MTBs and gunboats, handling their world-wide sales. acted as technical liaison officer with Denny Hovercraft Later, the company, which was part of De Havilland, was Ltd; latterly he was responsible for full-scale craft testing. absorbed by the Hawker Siddeley Group. Mr Piper was Mr Tattersall lives at Hythe, Southampton. partly responsible for setting up a new company (Hawker Siddeley Marine Ltd) to investigate marine projects, includ- Mr H. M. Watson ing hovercraft and hydrofoils. He was appointed Managing Youngest member of the board is Hilary Michael Director of Hovermarine Ltd at its inception in September Watson, the 32-year-old Engineering Director. Born in 1965. Mr Piper lives at Kenley, Surrey. (Continued on page 14) Three air cushion vehicles, after eight months of patrol Rolls-Royce Ltd has announced that it has formed a off the coasts of Vietnam and in ~tsmonsoon-flooded new division to handle all the company's business on interior, have been retuned to the United States. The US industrial and narine gas turbines. It will be known as Navy announced that they were brought back for "over- the Rolls-Rovce "Industrial and Marine Gas Turbine haul, modification and training of replacement crews". Division". The 7+-t0n anlphibious craft swung out of the open well The new division will be able to offer a wider range of deck of the USS Gunston Hall and swept ashore to the industrial and marine gas turbines based on aero engine Naval Amphibious Base at Coronado, California. Painted gas generators than any other manufacturer in the world. across their rubber bows were grinning mouths of sharks' The whole of thc gas turbine range of engines presently teeth, the designs scuffcd and worn by the craft's two weeks being manufactured and developed by the Rolls-Royce of fighting in the Plain of Reeds. Aero Engine Division and the Bristol Siddeley Aero Divj- The skimmers had been tested under a wide variety of sion and Srnall Engine Division will be available to it for conditions to determine their best military use. Textron's adaptation for industrial and marine purposes. Industrial Bell Aerosystems Company of Buffalo, New York, had and/or marine applications of Olympus, Avon, Proteus, delivered them to the Navy in . Tyne and Gnome are already in operation. The division is being formed by amalgamating the in- The Gunston Wall, landing dock, also brought back dustrial and marine gas turbine activities of the Aero two junks supplied by the Vietnamese Navy. They will be Engine Division of Rolls-Royce Etd at Derby and the used to train US Navy crews in procedures for Industrial Division of Bristol Siddeley Engines Ltd. Its stopping, and inspecting junks and sampans along South Vietnam's 1,000-mile-long coast and its numerous headquarters will be located at Ansty, near Covcntry, in the premises occupied by the Bristol Siddeley Industrial inland waterways. Division. The Cunrton Hall is similar to the USS Tortuga, the Managing Director of the division will be Mr W. F. LSD from which the three skimmers conducted coastal Saxton. Other members of the divisional board are to be: patrols for several months off South Vietnam. The Navy Mr W. H. Lindsey, Director of Engineering ; Mr F. T. Patrol Air Cushion Vehicles (PACV) also operated from a Blakey, Financial Controller and Commercial Director ; beach base at Cat Lo in river patrols against the Viet Cong. Mr A. H. Fletcher, Director of Marketing; Mr A. Jubb, Riding on a 43 ft thick cushion of air, the skimmers can Director of Future Projects ; and htfr R. W. F. Farthing, move over water, swampland, mud or dry land with equal Director. ease, at speeds up to 70 mph. Power is provided by a In consequence of the new division, Mr Saxton and Mr 1,000 hp gas turbine engine which drives the lift fan and Lindsey will cease to be members of the board of Bristol four-blade variable-pitch which pushes the craft Siddeley Engines Ltd. forward. Commenting on the new division, Sir Denning Pearson, The skimmers completed their Vietnam mission under Chief Executive and Deputy Chairman of Rolls-Royce, their own power despite bullet holes. None of the three said: "The potential market for industrial and marine was put out of service by the enemy hits, applications of gas rtubines is expanding rapidly and the The PACVs, with US Special Forces and Vietnamese new Rolls-Royce division will concentrate on satisfying this troops, formed an amphibious task force for the sweeps market. We look forward with confidence to a growing through the Viet Cong-held Plain of Reeds about seventy- future for this type of product, particularly in the export five miles west of Saigon. They were guided by field." at times through grass-like growth 12 ft tall. The area was Prior to the amalgamation of Rolls-Royce and Bristol just beginning to drain after the monsoon rains ; much of Siddeley, both companies had embarked on successful it was still under water. programmes of adapting gas turbines for industrial and The Plain of Reeds mission was named "Operation Quai marine applications. The creation of the new division is, Vat", adopting the Vietnamese word for "monster". In therefore, a logical integration of the two activities. addition to its crew of one officer and four enlisted men, The new division will start with a considerable back-log each craft carried an average of ten Vietnamese soldiers of business. At the present time more than 450 Olympus, and Special Forces personnel. Avon, Proteus, Tyne and Gnome industrial and marine gas The flotilla covered 220 miles from its jump-off point at turbines are in service, or have been ordered, for operation Cat Lo the first day, shooting up an enemy village on the around the world. The total value of export orders to date way to the craft's base camp at Moc Hoa. Lt-Cdr Charles is £1 5,000,000. Billings of the River Patrol Force served as tactical com- Following initial ordcrs by the Royal Navy in the late mander and Navy Lt Kenneth H. Luenser commanded 1950s and their continued support, ten other are PACV Division 107 (renamed Coastal Division 17 in operating, or have selected, the company's marine gas February). turbines to power naval craft. Its engines have also been Lt Luenser commented: "One Green Beret captain told chosen for the next generation of British gas-turbine- us that the area we covered in the last three days of our powered warships. operation would have taken him three months to cover. The Tyne and Proteus are powering prototype PGH-1 b They would have done it in sampans - and what is it, and PGH-2 patrol gunboat hydrofoils to be evaluated by one mile per hour, that you can get out of a sampan?" the , and the Tyne is fitted in the Moving over swamp and mud that was often waist- Grumman Dolphin class hydrofoil. All British gas turbine deep, the skimmer crews discovered and investigated 194 hovercraft to date are powered by the company's engines bunkers. They killed twenty-three Viet Cong in action and and in addition the Proteus has been designated the power captured eleven more. They destroyed seventy-one sampans unit for second generation military and civil hovercraft and an equal number of other structures, a Viet Cong now under construction. printing press, and captured rifles, hand grenades, small Industrial Olympus, Avon and Proteus gas turbines arms ammunition, medical kits and 60 1b of documents. operating on both gaseous and light distillate fuels are in Sr * -A. service or on order in Europe, the Near and Middle East, North and South America, Africa and the Canaries. These Details of the plan included encouraging the growth of engines are engaged on base load, peak lopping and stand- the sport of hovcrcrafting through the Hoverclub of Great by electrical generation, and gas and oil pumping duties. Britain ; orga~isinga National Rally to be held in the Isle In addition to the direct sale of its gas turbines around of Wight in June 1967 ; setting up area rallies and demon- the world the new division will have the backing of a num- strations at Autocross meetings and similar events through- ber of co-operation and licence agreements with overseas out the country. The means and guidance for the setting companies. Thcse include licence pr~ductionof engines and up of local clubs by enthusiasts will be provided. The spares, technical assistance and joint sales collaboration. Hoverclub already has members in many parts of the who it is hoped will form the nucleus of Particular emphasis will be placed on the study of all the local club movement. future possible applications of aero engine gas generators Technicians and engineers in the Hoverclub are already in all fields, and one of the directors will be exclusively working at a Player's club-prototype hovercraft and the concerned with this work. These studies will include "total advice of the Air Registration Board and the Board of energy" units and the use of the gas turbine for rail Trade has been sought in regard to safety requirements, traction. licensing and certifying of hovercraft. The Hover Award scheme, which has been designed to makc possible the development of the many technological A plan to develop the British-invented hovercraft as a features and other ideas which at present only exist as new popular sport and simultaneously to provide finance "backyard" projects, is to be open to three categories. for furthering British hovercraft technology was announced Major needs at present are : on February 7th, 1967, by the Hoverclub of Great Britain I. for improvemcnts in propulsion, braking and steer- and Nottingham tobacco manufacturers John Player & ing ; Sons. It includes a £5,000 hovercraft ideas award. 2. the hover system ; and The scheme has been worked out with the Hoverclub - 3. accurate instrumentation, for example the "speedo- the only club which exists in Britain to promote the in- meter''. terests of the user of small hovercraft. A four-point plan Prizes of £1,000 will be offered to amateurs who in the includes a Player's No 6 £5,000 Hover Award ; sponsorship opinion of a panel of experts produce the best ideas or of national and regional rallies ; setting up of affiliate clubs actual designs in each of these areas. throughout the country ; and publication of a definitive There will also be an inter-club Concours d'Elegance as hovercraft manual. well as a perpetual trophy for the most outstanding achieve- Announcing the plan, Mr Geoffrey Kent, a director of ment of the year in the design or use of hovercraft. The award is open for competitors as from March lst, Player's, said : "The scheme is conceived as a long-term aid 1967, and all entries must be received by the Hoverclub to a uniquely British enterprise. We are at present ahead by November 30th to be eligible for the current year's of the rest of the world in hovercraft technology and one awards. Details and application forms are available from purpose of the scheme will be to maintain that lead. the Hoverclub of Great Britain, 12113 Castle Street, , Industry as a whole should help to provide opportunities Isle of Wight. and the incentive for keeping the fruits of our national genius in this country. Publicity has recently spotlighted the * * * The Inca Arrow, a 27-passenger hydrofoil run by concern felt at the 'hover brain drain' overseas by top-level Crillon tours of La Paz, carries tourists on the waterleg professional engincers. Encouragement for the small man of the journey between La Paz and Lima. The trip across now should help to build a reservoir of talent. Lake Titicaca (12,500 ft up in the Andes) takes seven hours "We think, too, that hovercraft have a tremendous appeal with stops at Indian villages and Sun and Moon islands, for use in ways similar to power-boating and motoring. where the Inca empire is reputed to have had its beginning. We believe that this four-point plan will form the basis The Inca Arrow carries a hostess on board who describes for a constructive programme which will make hovercraft- the points of interest and serves coffee and snacks en route. ing a practical and exciting new sport." The tourist can travel from La Paz to Lima for $70. The Hoverclub of Great Britain was made up of enthu- The price includes overnight hotel accommodation in siasts and experts who were in the forefront of a new wave Puno, Peru, where passengers board the train for the ten of practical technology, said Mr Kent. His company had hour trip to Lima. The two hour ride from La Paz agreed to provide backing to help them and others move to the lake crosses the Altiplano where llamas and alpacas forward more quickly. graze, and the 18,000 ft high Andes serve as a magnificent Explaining the potential of the plan, Mr G. W. Dorley- backdrop. Brown, Secretary of the Hoverclub of Great Britain, said: A a k "The hovercraft, like the motor car and the aeroplane, Mr Dan Reece has resigned as director and chief developed from the genius and determination of a small designer of Lord Brassey's hovercraft company "Hover- number of men We believe that in the accelerating pace air". Mr Reece designed, built and piloted the prototype of modern society there is great potential for rapid and model which won &hehovercraft rally held in 1966. rewarding development of this British principle." * * * Big companies had their own resources, but today even An SR.N6 hovercraft is currently being demonstrated on simple ideas needed financial backing and long-term en- the Tagus River in Portugal, and the Portuguese are couragement on a permanent basis, he said. reportedly showing great interest in the craft for military "We are greatly encouraged by Player's agreement to purposes. It is considered ideal for use along rivers and take a long-term and comprehensive interest in British in the swampland of Portuguese Guinea where rebel insur- hovercrafting. Now that money has been made available in gents are still active. a practical and responsible manner we are confident that British policy is that she is prepared to sell weapons to we shall see real advances in technological achievement for Metropolitan Portugal as a fellow NATO member, but small hovercraft and in bringing a new and British pastime not for use in overseas provinces. Use would have to be to the fore." restricted to Metropolitan Portugal. aw, O.B.E.

This paper was presented to the Swedish Institute of Naval Architects, Stockholm, February 22nd, 1967

PEAKING in a country some of whose citizens have shown For places such as these the application of hovercraft has S the world thcir confidence in hovercraft by being the to be part of a very large-scale economic plan aimed at first to order a really big one, the 165-ton SR.N4, my using the new transport potential of the hovercraft concept choice of a subject may seem rather strange. However, I to change the whole environment. The enormous transport capacity of a single hovercraft, even when it is no bigger feel that we are only at the very beginning with this con- r) cept. Inevitably hovercraft have not yet reached their peak than the SR.N4, which is capable of transporting 10,000,000 performance or their most economic form, and for the ton-miles or 100,000,000 passenger-miles a year, dictates immediate future anyone engaging in hovercraft operation the scale of the economic plans in which they could be as a business venture will be very careful of his choice of used. It is fortunate that hovercraft by their nature are route. Traffic volume, route conditions, existing fare struc- very versatile carriers. In very large measure the same craft ture and the relative advantages to the traveller of the can be used to carry in the equipment needed to open up hovercraft's speed and terminal arrangements all affect the new territory as will be needed later to transport its people choice. In the narrows of the all these and their products and supplies. A particular type of area factors promise to be favourable for a craft the size of the where hovercrdft could come into their own- and this is SR.N4. For a still larger craft, if such existed, I believe of special interest to Sweden since you border on it -is they could be even more favourable. Certainly, the route the Arctic. At present no transport but aircraft serve these conditions, with the limits imposed for passenger comfort, regions throughout the year, and the limitations of aircraft would prevent the little SR.N6 from being an economic are obvious. Our trials last year with an SR.NS in Arctic proposition, for it achieved only 45% regularity evcn in Canada demonstrated very clearly the potential of hover- the summer months. Its main purpose was, however, to craft in these conditions. Even a craft as small as this gain experience of operations over the route. operated with almost complete freedom, Its ability to con- tinue operations at speed at night, even in poor visibility, Around the world there must be a number of short sea picking its way through the ice ridges using its radar, routes with similar conditions to the English Channel which greatly impressed the Canadians. There is no question in can be exploited with the SR.N4. When the craft has my mind that a larger craft such as the SR.N4 could been successfully demonstrated, doubtless other prospective revolutionise transport in the Arctic. operators will come forward. On some of the routes where There are three classes of hovercraft operations where the SR.N4 could be used, however, the traffic is highly strictly business considerations of making a profit on the seasonal, and the possibility should not be lost sight of hovercraft operation itself do not enter into the picture. that big hovercraft could be migratory. A journey of 1,000 Among these are Government operations, both civil and miles in reasonable weather conditions need take little military, and special-purpose operations such as explora- more than a day. When hovercraft fleets are large enough tion and survey, where the facility of the hovercraft makes; a proportion of the craft could be moved several times a possible an enterprise in itself profitable, which would be year between coinplementary routes. In this way services impossible or very restricted otherwise. We should not could be maintained but the frequency varied according to forget either the personal transport and recreational possi- the traffic. bilities of hovercraft in an increasingly affluent society. The In looking around the world for likely hovercraft opera- price of freedom, convenience and speed of movement is tions, the routes on which hovercraft could be operated far not always calculated very carefully. My reason for men- outnumber the routes on which the present traffic would tioning these non-profit-making classes of operation is that justify their operation. The concentrations of people in the they offer chances of immediate or early application of a world and the trasc that these imply are as much depen- hovercraft, substantially within the existing state of the art. dent on the transport that has been possible with available Describing them as non-profit-making is not to suggest that transport systc~:~C.~ on the location of natural resources. the requirements these operations set are necessarily easy There are vast areas, Brazil for example, with the resources to meet, Performance, safety, reliability, low first cost and largely untapped and very thinly populated, mainly because ease of maintenance are all demanded just as fiercely for the only transport routes available are unreliable rivers. them as for the commercial, profit-making craft. Among the classes of Government civil operations which So far as the mechanics of their lift is concerned, as would use hovercraft I would list medical and rescue ser- hovercraft get bigger they should get simpler. The lift air vices - particularly airfield crash rescue on some coastal is required mainly near the edges and I see no reason why airfields, firefighting, customs and police patrol, Speed and the requirements of a larger craft cannot be met by a all-weather availability are paramount in these roles. In simple multiplication of the fan systems of a smaller one. military use their logistic possibilities for beach landings The mechanics of the propulsion of hovercraft are a and all types of amphibious operation are obvious. In the difTerent matter. Up till now, with only one or two excep- naval role, fast patrol and interception and anti-submarine tions, hovercraft designs have relied on conventional air- operations are immediately attractive. In some degree craft or marine propellers. With air propellers there is hovercraft combine the virtues of the helicopter and the great scope for development, especially for hovercraft. The ship, and avoid some of their disadvantages. A large hover- requirements of propellers for aircraft and hovercraft are craft could provide a convenient helicopter platform, and different, and though it has been convenient to use aircraft the advantages of combining the two deserve examination. type propellers up till now, we believe that there are great In the UK we have been helped very much in hovercraft possibilities of improvement in economy and in noise level development by a steadily increasing interest and activity by designing specially for hovercraft. A programme of from the Defence side, and many of the development trials, propeller development is under way. An alternative form including the Canadian Arctic one, have been undertaken of air propulsion for hovercraft is being worked on in by our Inter-Services Hovercraft Trials TJnit. England by the firm of Cushioncraft Ltd, formerly Britten- Up till now the trends in hovercraft design have been Norman. They have built small hovercraft which use slow- along fairly narrowly prescribed lines. There is a strong running ducted fans for both lift and propulsion. These are family resemblance in the SR.Nl-6 series. These have all relatively very quiet craft but this form of propulsion is been air-propelled, fully alnphibious craft. With increasing not so efficient as a good propeller -possibly as low as size the number of lift fans has been increased from one to two-thirds the efficiency. However, though installing extra four, and the tendency to site these near the edges, where power is expensive, there would be balancing factors ; and the cushion air is delivered, tends to. leave the centre of fuel costs, though important, are not a major component the large craft unobstructed, a favourable trend. All the in operating costs. Cushioncraft have designs under way craft have an installed power of about 100 hp/ton, which for a small passengerlcar ferry, the CC-6, and for a rather does not itself suggest any improvement with increasing smaller passengerlfreight craft, the CC-7, both using this size, but when account is taken of the rather higher cruising propulsion system. speed, and the ability to continue operation in rougher seas, The advent of hovercraft, particularly for over-water there is clearly a favourable trend towards increasing operations, has directed attention to the problems, and in efficiency with increasing size. fact the general inadequacy, of water propellers for high A type of hovercraft which aims at a more modest per- speeds. Water propulsion, if the difficulties could be over- formance, but still high by ship standards, is the sidewall come, would have inherent advantages for hovercraft type of hovercraft. In broad ternis these craft currently use operating over water -low noise level for one. If some * about 50 hplton, about half the power of the pure hover- small degree of amphibious operation was required it craft, and they operate at about two-thirds the speed. might be tolerable to make provision for it in addition, Pioneered in the UK by the Denny Shipbuilding Company, even in a relatively inefficient way. I believe that a water the concept is experiencing a revival of interest both with propulsion system based on ducted propellers, for example, us and in the USA. A new company, Hovermarine Ltd, and the sidewall type of hovercraft is particularly well has been formed in England to exploit this concept. It is suited to this, could prove worth the effort of development. in many ways a direct rival of the hydrofoil craft, subject Exposed water propellers are particularly vulnerable on to some of the same operating limitations, but generally hovercraft because at speed these craft make little or no not to the same degree. A sidewall hovercraft is water- wash and so do not throw debris aside. borne and therefore needs some depth of water, but not so much as a hydrofoil craft. It likes clear water also, object- Anxiety is sometimes expressed about the control of ing to floating ice and debris, but is less vulnerable to these hovercraft because with the amphibious type they can be than a hydrofoil craft. Its design lends itself better than a seen moving with considerable sideslip, even broadside. An hydrofoil craft to installing a ducted water propulsion sys- airborne hovercraft tends to align itself with the relative tem, and thus one of the major problems of operating with wind, and when it is moving across wind will appear to be coating debris in the water could be overcome. I am not, yawed. In a turn also there is a natural tendency to skid. however, very confident of the all-season operation of such There is nothing particularly hazardous in this, and an craft around Sweden, but there are many parts of the experienced pilot with a properly designed craft can, if world where they can be used. circumstances require it, modify this behaviour as he wishes. A sidewall hovercraft of course is almost incapable In contrast with hydrofoil craft, where as size is increased of skidding and handles rather like a ! The control of a tendency to require an increasing proportion of structure a hovercraft in general is dependent on the variation and weight has to be fought with better materials and more deflection of thrust vectors, and in the nature of the craft refined engineering, hovercraft, it seems to me, pose a pro- the installed thrust is a small proportion of the craft weight, gressively simpler structural problem, at least so far as so that even if it could all be used to best advantage the their hard structure is concerned, as their size is increased. control forces and moments would still be small by aircraft I arn not so sure about the soft structure, the skirt systems. and road vehicle standards. By comparison with ship stan- In this area both the art and the science of design has to dards, however, the control available in a hovercraft is very be built up. However, since the fabric part represents only good. For example, the radius of the turning circle of the a small fraction of the structure weight, whether it in- creases or not with increasing size is not likely to affect the SR.N4 at 50 knots is 500 yards. overall result very much. I believe that, overall, as hover- All hovercraft in addition have exceptional stopping craft get bigger and we learn more about their structural capability over water. Simply by going into reverse pitch design, their percentage structure weights will get steadily on the propellers the SR.N4 will come to rest from 50 knots smaller. in 550 yards. In emergency the craft can be ditched by Built in the Rodriquez Shipyard at Messina. cutting the power also, and then the craft can come to a stop in less than 200 yards, say four to five craft lengths. At low speeds, off the cushion, the craft can be manoeuvred very precisely, even making deliberate lateral movements, something normally impractical with ships. In contrast to ships again, there is no reason to expect much reduction in manoeuvrability and control as the craft get larger. Over- land, however, hovercraft are at a disadvantage in control by comparison with conventional wheeled vehicles, and generally hovercraft require a fair amount of elbow room. Where it is justificd, however, craft can be fitted with small retractable wheels which take only a small fraction of the weight. Differential braking on these has been found to give very precise control at low speeds over smooth hard sur- faces such as concrete or tarmac. Finally, a word about legislation, since I gather you are considering this very much at the moment in Sweden. We in England are saying that hovercraft are hovercraft, and not ships or aircraft. It happens that they began their activity under the Ministry of Aviation and it was con- venient to treat them as aircraft and license their opera- tions under a permit to fly. As time has gone on they have begun to establish a character of their own and it is clear that they will require some new legislation. At the moment, however, we are thinking in terms of "holding" legislation, establishing responsibilities rather than defining detail regu- lations, which will follow as experience is gained. Their operation over land and over water will have to take account of regulations for existing traffic, but regulations for their construction and crews will depend on the nature of the hovercraft as a vehicle in its own right. The Gearbox is of paramount importance

where marine vessels are concerned, The light, high-speed diesel engines of hydro-foil-boats require equally effi- cient marine reversing gears. The ZF Gearbox fully satisfies this demand. It is light, easy to operate and extremely reliable. Our production range includes power transmissions from 10 to 3,000 H.P. Please ask for leaflets and instal- e and Projects lation proposals. (Contirzued from page 9) West Kilbride, Ayrshire, and educated as an apprentice to Fairlie Yacht Slip, and studied at Paisley Technical College. After spending two years with Sharp & Co, of Richborough, Kent, manufacturers of gear, he served three years with Denny Hovercraft Etd, working on hovercraft, and joined Hovermarine in 1966. Mr Watson's home is in Southampton.

Mr J. D. C. Stone, FCA Sole Agent for the U. K.: The company's Financial Director is James Drake Harold Ludicke Engineers Ltd. Colborne Stone, sixty. He comes from Ealing, Middlesex, 79, Alexandra Road and was educated at Wolverhampton Grammar School. He has been forty-two years in his profession, and for London, N. W. 8 many years has been senior partner of Messrs West & Phone: MAlda Vale 27 29 Drake, which firm is now incorporated in Allfields, of Arundel Street, London, who act as accountants to Hover- marine. He lives at Brookmans Park, Herts. ZAHlr~iRADFABRIKFRIEDRICHSHAFEN AG On February Sfh, 1967, the first air-stabilised Supramar PT 50 hydrofoil craft Flipper was demonstrated at Mandal, Norway, on invitation of the Westermoen Shipyard. The 65-ton vessel was built several years ago by this yard and then, at the end of last year, supplied with a fully sub- merged air-stabilised rear foil in place of the conventional surface-piercing configuration. More than fifty representatives of Scandinavian and British shipping coinpanies, classification and ship control companies, the Norwegian Navy, n German shipyard and towing test station, the ltalian and Japanese Supramar iicensees as well as a number of newspaper correspondents attended the dernonstratiolns on a seventy-mile trip from Mandal to Kri,stiansand und return. second Westermoen- built unstabilised PT 50 was operated side by side with Flipper, and acceleration measurements were made simul- taneously on both craft. Unfortrrnately, the highest waves on this day scarcely reached 3 ft; thus the important improvements of the new system were not much in evidence. However, during similar measurements which were made on the preceding day, average wave heights from 4 ft to over 6 ft were encountered. After the demonstrations, the stabilised craft departed for Copenhagen, where it will be for a short period of time in passenger service between Copenhagen and Aarhus; Denmark, under heavy sea conditions.

INTRODUCTION ODERN development of transportation means is M directed towards increasing the speed and riding comfort of the craft. Under improving the comfort it is understood here, in the physical sense, the reduction of vertical and lateral accelerations to which passengers are exposed while travelling in such craft. In the efforts to decrease uncomfortable accelerations, by far the most diffi- cult problems are encountered in water-craft as compared to all other means of transportation. Whilst land vehicles can attain an easy ride on modern smooth roads and rails, and aircraft avoid atmospheric motions by flying at high altitudes, water-craft must combat directly the waves which are encountered on their way to the destination point. Indeed, experience gained by Supramar from a ten-year operation with the surface-piercing foil system in various continents has taught us that the stress on passengers in heavy seas can become too great. The craft are then sub- jected to abruptly induced rolling and pitching oscillations with accompanying accelerations. If these accelerations exceed about 0.25 g, then the ride is no longer agreeable for the passengers, who can be exposed to such conditions for only a limited time. As a consequence, the number of passengers drops - at least during stormy periods - on such routes and the lines become unprofitable. This means that a great number of routes, which could be operated economically, cannot yet be served by hydrofoil boats. From the commercial point of view the problem of sea- worthiness cannot be solved by simply increasing the dis- placement. Apart from the cases in which the number of passengers available does not justify the use of a larger vessel, the advantage of smaller fast craft is lost. This advantage consists in low investment. small risk and in the well-known fact that a shuttle service with many small units rcsults in a higher passenger frequency than a service at long intervals with large units. Besides, the shuttle schedule is less affected by the stoppage or failure of a single boat out of several in service. Knowledge of these facts made it necessary to develop a system which offers the passenger an agreeable trip in smaller boats in seaway conditions, under which the travellers, for the present, still prefer other means of transportation. Not only would the number of passengers increased and of a heaving foil portion reduced. Hitherto increase on the existing lines, but many ferry services could the change of lift was brought about by change of angle be initiated which are presently not established by the of attack of the foil, or by deflection of flaps which are shipping companies in view of existing sea conditions. hinged to the trailing edge of the foil. This kind of lift control requires high torque moment for the foil or flap PRESENT TECHNICAL STAGE actuation and consequently voluminous hydraulic devices Before describing the new technical solution which was (see Fig 1, upper part). found by Supramar for the improvement of seaworthiness The Schertel-Supramar air-control is based on new and riding comfort, a short abstract of the! properties of physical principles. Air is admitted, or better sucked in, the presently known two basic foil systems is given for the from the free atmosphere via ducts and air-exit openings sake of better understanding: on the foil surface into its low pressure regions. The As is known, the inherently stable surface-piercing foil air-flow decreases the suction on the surface and is deflected system is distinguished by its simplicity, functional reliability away from the contour with an effect similar to that of a and low initial and maintenance costs. Up to the present defiected flap. Simultaneously there is a virtual lengthening time these properties contributed towards the acceptance of of the profile generated by the air cavities extending behind this hydrofoil system as the only one economically feasible the foil. As d result lift is reduced and varies with the for international passenger service. The disadvantage of the admitted quantity of air, which in turn is controlled by a system can be seen in its relatively hard riding character- valve (see Fig 1, lower part). istics in open sea conditions. When cruising in a following Thus a lift control of the simplest and most reliable sea, the pitching angles, caused by the orbital motions in design has been created which requires neither electric or waves, can become so large that the hull sometimes touches hydraulic power sources nor pivotable foils or flaps. The the wave crests and sustains considerable speed losses. mechanical work which must be performed for varying lift The automatically controlled fully submerged foil system by means of air valves is only in the order of 1 /30,000 of experiences smaller and smoother rolling and pitching that required for actuating the flaps. Initial costs are low motions than the first described foil configuration and and maintenance, compared with the electronic control, so passengers therefore travel in greater comfort. Also a better platform is provided for weapons or instrument systems in military craft, However, these advantages are only rcalised with a complicated electronic-hydraulic control system, which must function faultlessly to maintain the proper per- formance of the boat. These difficulties, and the very high construction costs, have contributed to the present situation where this electronic system has not yet found application in passenger servicc where profit must be made. The described stage of development at which good sea- Flap controlled lift behaviour can only be achieved by considerable technical and financial effort, gave rise to the desire to find a system which embodies the simplicity, reliability and the low initial and maintenance costs of the surface-piercing system but approaches the seakeeping qualities of the fully submerged foil arrangement. However, this posed the task that such hydraulic acfuator a system would warrant sufficient operational safety in order to be accepted by shipowners, naval authorities and classification companies. On the other hand, Supramar's objective is to convert these vessels now in operation from the old to the new system with a relatively small amount of cost and time. This result had a two-fold advantage for Supramar - improvement of the seakeeping qualities of the present boats in operation, and availability to the naval authorities of hydrofoil craft capable of fulfilling their respective requirements. DESCRIPTION OF THE SYSTEM Air confroiled iift The solution which has been found and developed by Supramar during the past several years is a system which p d;= 1/30 000 P.D includes a surface-piercing front foil of reduced auto- stability and a fully submerged air-stabilised rear foil. The air-stabilisation must be divided into two parts : the air-feeding system of the foil for producing lift variations, and the air admittance controlling device which in turn is operated automatically by sensors responding to the motion of the craft. (a) The Air-f eed System of the Foil A ship stabilisation system, as is known, reduces the roll angles in waves by producing restoring moments. In the case of hydrofoil boats, the stabilisation for rolling and for Ib, pitching is effected automatically by changing lift on foil parts in such a way that lift of a lowering foil portion is Figure I Figure 3

the effectiveness of the artificial roll-stabilisation of the rear foil on the other hand. It is obvious that the more rolling angles can be reduced, the more the natural front foil stability is exceeded by the recovering moment of the artificial stern foil stabilisation which does - as known - not respond to the wave contour, but tends to maintain the craft's horizontal position. The bowfoil also is used for roll stabilisation by provid-

V= Valve A~Amplifier G=Rate Gyro P-Pendulum Ac = Accelerometer . ing it with a centre strut with alternating control air-feeding to both sides of its lower immersed part. The moments producing area of the strut has a very large lever arm to Block Diagram of the centre of gravity of the boat, and the stabilisation is therefore very effective, almost doubling the restoring moments of the roll stabilisation. The respective sensor arrangement is seen in Fig 2, upper part. This control configuration, however, requires modifications on the bow- foil of the already existing Supramar boats. easy that the control can be handled by normally trained The submergence depth stability is ensured by the natural ship's personnel. auto-stability of the surface-piercing front foil. The trouble- free maintenance of the submergence depth by its inherent (b) The Autoar~aticAir Quantity Control Device stability is the main difference to the fully submerged The air quantity controlling valve is actuated by the system which, for this function, so far required an expen- mechani~allyadded signals of a damped pendulum and a sive, complicated electronic control device, e.g. ultrasonic rate gyro. The pendulum causes righting moments at sensors. static lists. If it is exposed to a centrifugal force in turning, The dynamic submergence stability of the front foil can it causes a moment, which is directed towards the centre be increascd by an artificial stabilisation in which the air of the turning circle, thus avoiding outside banking of the valve is controlled by an accelerometer or a device which craft. Tlne rate gyro responds to angular velocity and acts senses lift variations caused by the orbital motion in waves dynamically in the sense of damping rolling motions. The (see Fig 2, upper part). This arrangement rcduces vertical signals of the sensors are added by a summation lever and accelerations of the front foil and thereby also the pitching then amplified by only a small and simple pneumatic angles, thus preventing the impacting of the hull into wave amplifier which receives its propulsive force by the suction crests in a following sea in a more effective way than with formed at the strut, so that no pump is required (see block the air stabilisation on the rear foil alone. diagram, Fig 2). The pitch-stability is niaintained by the auto-stabilisation The described stabilisation devices are housed in water- of front and rear foils. It is known that the fully sub- tight casings (see Fig 3) which are installed above the merged rear foil has a natural submergence stability in rudders for controlling the rear foil. tandem arrangement with the front foil, because variations from its submergence depth are connected with restoring 1 (c) Maintenance of Stability changes of angle of attack which occur when pivoting With the aid of the control system described under (a) about the front foil. The pitching angles are reduced by and (b), the stability of the craft is maintained in the the artificial stabilisation of the rear foil. It is obvious that following way : in this case both valves on the rear foil are actuated in the The roll-stability is kept jointly by the natural auto. same sense by the two rate gyros, whereas the pendulum stability of the surface-piercing front foil and the artificial only responds to rolling motions. stability of the fully submerged rear foil. Hereby is the With regard to the seaworthiness to be expected from normally provided natural roll-stability of the front foil the described partly stabilised system as compared with reduced to almost indifferent static stability in order to the fully stabilised boat, one has to realise that the surface- decrease the water impact on the front foil and to increase piercing front foil as well as the submergence depth sensing device of the fully submerged foil respond to the was provided m7ith the described centre strut with alter- wave contour at a rate which depends on the foil's sub- natively controlled air-feed to both sides. mergence characteristic. Since both systems can receive the The systcm was submitted to a one-month trial period same characteristic, and since nearly the same effectiveness in the wash of passenger steamers and in wind-waves which can b:: obtained with the two roll and pitch stabilisations, were only moderate on the Lake of Lucerne during the theoretically the same seaway behaviour results for both test time. The results were vcry satisfactory. A very high systems, provided that the surface-piercing front foil is degree of transversal stability with strong damped rolling supplied with an orbital influence or acceleration sensing motions could be established. The rolling angles at about device. The preponderance of the fully submerged system 0.5 m wave height were only +. 2". Transferred to PT 50, consists merely in the changeability of its submergence a corresponding wave height of 1.2 m for the same rolling characteristic at will, and because a damping or short-wave angle could be anticipated. The abruptly induced rolling filtering function can be introduced, allowing an adaptation movements of the conventional surface-piercing foil system to the seaway conditions. In addition to this and under the were no longer felt. The stabilisation completely eliminated assumption that the dihedral foil would have a smaller the directional instability which was experienced with the mean submergence than the fully submerged foil, the latter unstabilised boat. would be exposed in short waves to the orbital motion with As a very important result, it became apparent that the a smaller amplitude because this decreases with the water stabilised craft could pass through all steamer waves in depth. their running direction without any extensive hull im- However, the considered part-air-stabilised boat offers mersion, whilst with the pitch-stabilisation off, the hull very important advantages over the craft with fully sub- repeatedly crashed into the waves. merged foil. These are, above all, simplicity, low cost and Mr Westerrnoen attended some tests with the experi- operational safety. The boat is able to continue its travel mental boat and found the results so convincing that "foilborne" at somewhat reduced speed in case of a very he decided to supply the PT 50 craft Flipper with a fully improbable failure of the air stabilisation, whilst the vessel submerged air-controlled rear foil (see Fig 5). No modifi- with fully submerged foils becomes inoperative in such cations were made on the bowfoil which, in the opinion cases, and can only proceed in a displacement condition. of Suyramar, only requires stabilisation if a boat is to be This capability of the part-stabilised craft is an essential subjected to very heavy sea conditions. factor for keeping to the timetable. Even greater is its TRIALS WITH THE S'TABILISED PT 50 importance for military craft. The modification work on the PT 50 Flipper was com- TESTS WITH AIR-STABILISED EXPERIMENTAL pleted in the middle of January 1967. The first test run was BOAT made on January 21st. The stabilisation worked well from In order to test the new conception, the foil configura- the very beginning and its effect immediately became tion of an existing 4-ton PT 3 boat was changed. A fully apparent when th,c boat encountered the first waves. The submerged air-controlled rear foil (see Fig 4) was installed crew could walk freely on board in a sea state where every- in place of the original surface-piercing foil. The bowfoil body would otherwise have had to hold on in the un- stabilised craft. At the end of January and beginning of February, tests were very much impaired by cold weather, ice and snow storms, so that only little experience had been gained when the comparative tests and demonstration took place with the stabilised Flipper and a second boat of the conventional type PT 50, both supplied with accelera- tion recording instruments. The first day (February 7th), with waves of 1.5 m average height, was very instructive. Whilst the conventional craft in one case frequently dipped into wave crests to such an extent that the front foil tip became submerged, Flipper ran smoothly with perceptibly smaller roll and pitch angles. Unfortunately, the accelerometers were on this day insufi- ciently damped, so that the accelerations could not be

Figure 4 Figure 5 clearly distinguished from the vibration traces. Therefore only an approximation could be made, which gives as result a transversal acceleration for Flipper of 0.12-0.15 g LEOPOLDO RODRlQUEZ and a four times higher value for the unstabilised boat. According to visual horizon bearings, mean rolling angles SHIPYARD of the unstabilised craft were also about four times larger MESSINA - ITALY than those of Flipper., which showed scarcely fi 2" in quite good correspondence with the anticipated value based on the experimental craft trials. On the second day (February 8th), in waves of about 0.5 m height, the ratio of lateral accelerations was only about 1 : 3, as it has to be expected in low waves. Licensed by Supramar A.G. Zug-Switzerland The vertical accelerations had not been measured on the first day. The mean values on the second day, when inter- The polated between bow and rear foil, were for Flipper about 0.07 g and for the conventional PT 50 approximately 0.13 g. Greatest Experience The pitch stabilisation applied for Flipper is only effec- tive at relatively short wave-encountering periods. The in reason for this is that the used rate gyro as sensor responds Hydrofoil Boat Building inadequately to slow oscillation. This deficiency will be corrected. The stabilised Flipper is somewhat slower in smooth water than the unstabilised craft due to additional air-feed drag. In the case of a flap-controlled foil a similar speed drop would occur because a part of the engine output must be used for the hydraulic actuation. It has to be mentioned that tank tests showed that air-feed drag decreases with growing speed and can become null. The trials at Mandal proved, however, that Flipper is faster in a seaway on account of her smaller oscillations and reduced hull-wave Hydrofoil Boats Across contact. It is intended to continue the measurements with boats The World's Seas running side by side in order to establish the advantages of air stabilisation more thoroughly. A in 18 Countries The Westerrnoen Shipyard has a 150-ton combined passenger and car ferry (a Supramar PT 150 design) under construction. The decision has already been taken that this type will have an air-stabilised rear and front foil.

THE HISTORY OF AIR CUSHION VEHICLES

by Leslie Hayward

ANY KIND UK and Europe, 5s 6d (incl. postage) sf SHIP REPAIRS The d's Larges Hovercraf The SR.N4 at Co

by Terence Ford C. Eng, AFRAeS

The SR.N4 with a normal operating weight of 165 tons is considered to be the optimum size of hovercraft for operation over open coastal waters. It will be capable of maintaining services in seas of up to 12 ft wave heights at speeds of up to 70 knots over stage lengths of 100 miles. The basic craft will be able to carry 50 tons of payload, equivalent to 34 and 174 seated passengers, but several alternative versions have been proposed; for example one carrying 30 cars and 254 passengers, or an all-passenger version-for609. '

STRUCTURAL FEATURES fi \ BAGGAGE i EAGGAGE CREW DOOR LAYOUT OF BASIC CRAFT I74 PASSENGERS 34 CARS

Length, overall ...... Basic craft - 34 cars and 174 passengers Beam, overall ...... Basic weight ...... 101.5 tons (1 03,l totlnes) Height, overall ...... D,isposable load : Bow ramp aperture . . . Crew ...... 0.45 Stern door aperture . . . Cars, passengers Vehicle deck headroom . . . and luggage 50.55 Cushion area ...... Fuel ...... 12.0 Cushion loading at 165 tons AUW Total . .. 63.0 63 tons Buoyancy reserve at Normal AUW ...... 164.5 tons (167,l tonnes) 165 tons AUW 250% (total buoyancy approx Mean operating weight . . . 147.5 tons (158 tonnes) 550 tons)

POWER PLANTS AND TRANSMISSION Engines : Main ...... Four Bristol "Marine Proteus" Max speed (optimum gas turbines trim) : Max continuous power 3,400 shp Max power ...... 77 knots (143 krn/hr) Max permissible power 4,250 shp Max cont power . . . 70 knots (130 km/hr) Auxiliary ...... Two Rover IS190 gas turbines Service average speed : Transmission ...... BHC integrated drive for lift fan max cont power . . . 6 1 knots (1 13 km/hr) and propulsion propeller Airspeed into wind in

Propellers , . . . Four Hawker Siddeley Dynamics, 4-5 ft waves (Channel four-bladed, 19 ft (5,s m) dia, type seas) ...... 56-65 knots (102-120 km/hr) controllable pitch Airspeed into wind in . . . . . Four BHC twelve-bladed, 11 ft 6 in 8-10 ft waves (Channel) (3,s m) dia centrifugal, fixed type seas) ...... 50-60 knots (93-1 11 km/hr) pitch Time to accelerate to Flexible trunks ...... 7 ft (2,13 m) combination type 50 knots ...... 55 sec EAR~ENINGproof of the present healthy state of the H hovercraft industry in this couiltry and the ambitious plans for ~tsfuture weie evident during a recent vlslt to the SR N4 production lrne at the works of the Brrtish Ilovercraft Corporation The first SR N4 1s now recognisably a large capacity craft and the Inner bulkheads have been added, enabllng an overall Impression of he~ght as well as of spaciousness to be gained. Thls hovercraft 1s due to be completed in the autumn and to be delivered to Brltish Rail in the early part of next year, while the second SR N4 will coinmence service with Hoverlloyd In May 1968 The SK N4 1s an all-metal crdft constructed chiefly of llght alloy materials and powered by four Bristol Siddeley Marine Proteus gas turbine engines mounted in pairs In two engine rooms at the rear of the craft, each engine drlvlng a propulsion propeller and centrifugal lifting fan The pi opcllers are mounted on pylons wh~chcan be pivoted to change the d~rectlonof thrust and control the craft, and Buoyuncy compartments almost completed and decking of the fins mounted aft of the rear propellers move in conjunctlon whole areri in process with the rear pylons to glve additional directlo~lalstability which 1s further enhanced by geared rudders The buoyancy tank and bow are divided into twenty-four The propeller transmission also drives the l~ftingfans watertight compartments so that even a rlp from end to which are mounted below each propeller. Air is drawn by end would not cause the craft to sink or overturn In the the fan through intakes on each side of the pylon and consldcration of stability calculations, the compartments of directed through plenum chambers under the passenger the bow structuie togethel wlth the inherent buoyancy of cabins into the peripheral trunks, from where il is directed the sandwich panels used for the major horizontal surfaces inboard beneath the craft to create the air cushion. The have been neglected, although in fact they are quite con- control cabin is situated on the cabin roof ahead of the siderable. Nevertheless the reserve buoyancy is over 250% forward pylons and provides accommodation for three crew -that 1s to say, more than 550 tons. plus one supernumerary. Standardlscd components are used throughout the SR.N4, more so than with any prevrous hovercraft, and a typical example of th~ais the basic structural grid, which IS made Structural Features of sections 94 rn long by 473 in wide and built up of light In the design of the SR.N4 particular attention ha.: been alloy panels stiffened where necessary On top of these paid to minimising the amount of day-to-day rnaintenancc sections is placed the main car deck, lncorporatlng a non- C required to be undertaken by an operator, and to this end slip surface All horizontal surfaces are constructed of pre- reliable components and systems of proved long life have fabrrcated sandwich panels with the exception of the roof, been coinblned with an essentially simple structure. which is of skin and stringer panels. Double curvature ha3 The central main deck accommodates cars, while the been avoided other than in the reglon of the air intakes and passenger cabins are along the sides of the craft and raised the bow above the level of the car deck. At the forward end of the The structural grid, as well as having the buoyancy tank vehicle deck is a l~ydraulically-operatedramp which com- built aiound it, also governs the superstructure, being main- pletely seals off the deck when raised and enables the cars tamed on the elevated passenger decks and the roof, where to drive off when lowcred. The deck of the craft prior to the panels are supported by deep transverse and longi- the fitting of the bulkheads is an impressive slght with an tudinal frames The buoyancy tank 1s joined to the roof by overall length of 130 ft 2 in and a beam of 76 ft 10 in, longltud~nalwalls, forming a st~fffore-and-aft structure, appearing at this stage as one continuous area. At the aft and the tank is also desrgned to take any lateral bend~ng end of the car deck provision has been made for double doors extending the full width of the deck, while the passenger doors are in the sides of the craft and these, together with retractable stairs, enable the passengers to embark or disembark concurrently with the cars. Steps give access from the car deck to both the forward and centre passenger cabins, these being 3 ft above the car deck. With the engines situated well aft, a low noise level is realisable in the passengel cabins because of the extensive use made of modern soundproofing techniqucs and materials. In the basic craft illustrated, 174 passenger seats are shown together with baggage stowage space and two toilets. The car capacity of this particular layout is thirty-four, based upon a random select~onof a typical payload. Trans- verse width of the car deck (32 ft at the ends) is such that reasonable passageways may be left for passenger access. On the assumption that each car carries an average of four passengers and that they remain in their cars, a 100% capacity payload for this layout would be 61 tons and the AUW with maximum fuel would be 176 tons. Installing the first major bulkhead Inner bulkhead

'The top and bottom surfaces of the tank cons~stof panel\ bolted on to the frames, the upper surface formlng the vehlcle deck. Ovcr the centre 16 ft of thls deck the panels ale reinforced to carry vehicles of a maxlmum unladen welght up to 9 tons (axle load 13,000 lb), whrle the remainder IS designed to carry lrghter vehlcles wlth a maxlmum axle load of up to 4,500 Ib. The articulated loading ramp 1s 18 ft wldc and 1s bullt Into the forward end of the craft On to the underslde of the buoyancy chamber ale bullt five sprung landing pads of 2+ ft diameter, which elve a ground clearance of 21 Close-up showing mairl car declc with non-sli~r surface in at nornlal all-up weight. As us~din prevlous BHC hover- posrtion crait, a systeni of per~pheral trunks wlth a thwartship stability trunk 1s burlt Into the SR N4. but the method by Q whlch the air 1s d~rectedhas been altered so that the ali In thz slde and bow trunks is ci~rectcd lnto the cushlon through a serles of fingers whlch form the lower thlrd of tile trunks The aft and stablllly trunks are sim~larIn con- structlon to the s~detrunks but dlffer 111 that the alr is dlrected Into the cushron through Inverted cones The mater~alused for the trunks 1s neoprene-coated nylon fabr~c and that for the fingers arid cones IS the same, but of much l~ghterwelght 11 1s the greater flexlbrlity of the lower por- tlon of the trunks that contributes in no small way to rmproved control, stablllty and cornfort

Inner bulkkcad on the SR.NI. Note the nasjewgcr deck which Close-up of buoyancy tank framework is 3 ft above the level oj the car deck Power Plants and Tra~lsmission Each of the Marine Proteus engines drives one of four identical propeller/fan units, two forward and two aft. The propulsion propellers are Hawker Siddeley Dynamics four-bladed type with variable and reversible pitch and are 19 ft in diameter, while the BHC lift fans are centri- fugal and twelve-bladed and of 11 ft 6 in diameter. The Proteus engine fitted in the SR.N4 develops 3,400 shp at continuous rating and up to 4,250shp for emergency conditions or for limiled use in extreme weather condi- tions. The power distribution is accomplished by means of integrated lift/propulsion-- that is, since the gear ratios between the engine, fan and propeller are fixed, by chang- ing the propeller pitch and hence varying the speed of the system, the power absorbed by the fixed pitch fan is also altered. This power can be varied from almost zero to 2,100 shp within the engine speed limitations. A typical division at max cruise power would be 2,000 shp to the propeller and 1,150 shp to the fan, the remaining 250 shp being accounted for by engine power fall-off due to the turbine rpm drop, transmission losses and the auxiliary drives. Accessibility of the engine is a most important feature of the engine room layout and it is envisaged that an engine change will be possible in three to four hours. The drive shafts from the engine are flanged light alloy tubes 74 ft long supported by steady bearings and con- nected by self-aligning couplings. The shafting to the rear propeller/fan units is quite short but is about 60 ft to the forward units. In an accompanying figure is shown the variation of engine output power in ISA conditions with turbine speed for a range of compressor rpm with craft operating con- ditions superimposed. In most conditions anticipated, the

engine would be operating within the area shown and to achieve the performance indicated here the compressor would need to be run at 11,250 rpm7 which is the cruise or maximum continuous rating of the engine. It is emphasised that operation at higher compressor speeds is of course possible up to the maximum value of 11,750 rpm, corres- ponding to 4,200 shp from each engine at the maximum turbine speed of 10,720 rpm, but that this will greatly reduce the engine life. Operators are advised that if they can achieve power ratings below maximum on their schedules, if only occasionally, the engine life will be appreciably increased. At temperatures above TSA, the engine output at a par- ticular compressor speed or throttle setting falls with increase in temperature, by about 0.8% per degree C rise at the maximum continuous rating, and rises with decrease in temperature. To achieve a high engine life it is recom- mended that in cold climates the engine output is restricted to a maximum of 3,400 shp. In normal operation, the turbine speed will vary from 6,800 rpm, where the fan will generate a pressure sufficient to lift off the craft, up to the maximum turbine speed which is governed to 10,720 rpm. Within this operating range of the turbine, the minimum power required from the engine is given by the lower boundary of the operating region. The main gearbox of each unit consists of a spiral bevel reduction gear with outputs at the top and bottom of the box to the vertical propeller and fan drive shafts respec- tively. The vertical shafts and couplings are similar to the main transmission shafts except that the shafts above the main gearbox are of steel instead of light alloy so that they ENGINE OPERATING CONDITIONS can transmit the greater torque loads to the propeller. This gearbox is equipped with the means to take off power to drive an auxiliary gearbox with drives for pressure and scavenge lubricating oil pumps as well as a hydraulic pump for the pylon and fin steering control. The upper gearbox, mounted on top of the pylon, tur~lsthe propeller drive through 90" and has a gear ratio of 1.16 to 1, and has its own self-contained lubricating system. Accessibility for maintenance is a feature of the engines and auxiliaries, RUDDER BAR WHEEL which can all be reached from inside the craft, while engines, propellers, pylons and all gearboxes can be re- moved for overhaul without dlsturbi~lgthe main structure. PYLON AND FIN ANGLE The lift fan itself rotatcs on a pintle which is attached to the main structure, and th~sassembly may be detached and

I removed inboard on to the car deck wlthout the necessity RUDDER 8Aii COLUMN of removing any main components.

Craft Control The controls in the cabin rnclude a rudder bar for steer- ing the craft and the commander achieves this by pivoting the propeller pylons differentially - that is to say, if the right foot is moved forward the forward pylons move clockwise, viewed from above, and the aft pylons and fins move anti-clockwise, thus producing a turning moment to starboard. Rudder bar movement also varies the pqopeller blade angles differentially so that the craft's turning moment produced by pylon and fin movement is further increased.

It has been emphasised that this method of control is PROPEL\-ER PITCH essentially a double SR.N3 system in which the thrust lines and pitch angles of the propellers can be varied either collectively or differentrally. The pylons, fins and rudders move thtough angles of +-35", -+30° and &40°, respec- tively. Both positive thrust on the propellers (as described above) and negative thrust is obtainable, as in using the propellers for braking, but m the latter case the pylons * and fins are automatically turned to opposing angles, thus maintaining the turn. A wheel mounted on a control ACTUATOR column enables the commander to move the pylons and THROTTLE CONTROL fin? in unison to produce a drift to either port or starboard DIAGRAM OF CONTROL SYSTEM as required, and collective variation of the propeller pitch angles, and hence control of the d~stribution of power it serves as a ballast system and by the necessity to keep between propellers and fans, is made by fore-and-aft move- the main tanks outside the area of the vehicle deck. Safety ments of the control wheel used in conjunction with the considerations dictated the latter requirement - for ex- engine throttle levers. In the accompanying diagram of the ample, running the system pipes along the outside of the control system, the groups of pick-offs for each signalling buoyancy tank away from the top surface where they might system are shown at each of the commander's controls. be damaged by debris ingested by the fan. The fuel is The electrrcal circuits are fed from a DC supply and will contained in four groups of three bag-type tanks contained continue to operate in the event of a complete generation within fuel-tight compartments, with a total usable capacity failure - a most unlikely contingency. of 4,500 gallons (16 tons). The basic crew requirement is for a commander, an Each group of tanks is fitted with an engine feed pump engineerlradio operator and a radar operatorlnavigator, and two larger pumps which transfer fuel in the event of a while a seat is provided for a fourth crew member or a main feed pump failure, or for trimming purposes. The crew member under training. The remainder of the crew large pumps are designed to be able to transfer 4 tons of are concerned with passenger service or car handling and fuel longitudinally or laterally in 53 minutes. In the event are located in the main cabins, although, of course. this of failure of any one engine feed pump, the supply to the arrangement may be modified to suit individual operators' associated engine is maintained automatically, its supply requirements. Access to the control cabin is by two pipe being connected to that of the other engine on that methods: when cars are arranged in four lanes, a hatch sida of the craft. To prevent a situation where two engines 1. in the cabin floor 1s reached by a ladder from the car were then being supplied from the same source, two means deck, but when heavy vehicles are carried on the centre are adopted: either fuel can be transferred into the tank !atle, a door in the port side of the passenger cabin gives or the transfer pumps in the relevant tank are used in access to a ladder leading on to the main cabin roof from place of the failed pump, after opening a cock in the feed where an entrance door into the cabin can be reached. llne. Transfer of fuel 1s an automatic operation insofar as the associated transfer cock, the transfer pumps in the tanks Systems from which Iha fuel is to be transferred and the refuelling The fuel system has been designed for maximum relia- valve in the receiving tank are operated simultaneously by bility in the event of the failure of a pump or similar the closing of a switch after the required sequence has been component and has been greatly influenced by the fact that selected. Electrical power is supplicd by turbo-alternators driven orno by two Rover 1S/90 auxiliary power units (APUs), one SCALE IN FEET being housed in each of the port and starboard engine rooms. Fuel is supplied to the auxiliary power units from the main tanks by a DC generator which can be operated from the main batteries, enabling the APUs to be started before the main engines. A pressure refuelling point is provided on either side of the craft, each one being designed for a refuelling rate of 300 gallons per minute. If the two re- fuelling points arc used simultaneously, the craft can take I IN I5 RAMP on a normal fuel load in six minutes. The arrangernent of the hydraulic system gives a high degree of safety over the control of the craft, since the ,/C"lloMs ;Ihl*iiO)

failure of any one component cannot affect another system. . .CAR PARK FOR CUITOUS Long pipelines which would normally be associated with a I IN I SLOPE.-__ craft of this size have been avoided. There are eight separate hydraulic systems, two of which are electro- hydraulic, one for the actuation of the bow ramp, star- board fan intake shutters and passenger stairs, and the I. ~4-- --

other for operating the rear doors, the port fan intake BARRIER MBARXATION CAR PARK shutters and the passenger steps. Each pylon also has its USTOMS (OUTWAPO)

AINTLIIANCL JACKS own self-contained system driven from its main gearbox ANCLL BLTYFFN RA MA" BP RC0"Ci0 , comprising pump, filter, servo valves, jacks and tanks, while IU~T erii LNwirbilo the fins are operated by similar systems. Four feed pumps, one on each of the propeller gearboxes, supply oil pressure i iN ii RAMP---- to actuate the propeller pitch change mechanism, and in

addition a hydraulic parking brake is provided for each 'CFNLRAL CAR PARK transmission system which is manually operated by levers adjacent to each fan. A11 the cngines and gearboxes are independently pressure- lubricated and a failure in any lubrication system affects only its associated equipment and will, at the worst, cause only a shut-down of one engine/propeller/fan unit. Before starting the main engines, one of the APUs must be started from the two 28v batteries. This provides AC power which is rectified using full-wave rectifiers to pro- HOVERPORT FOR AN INTERNATIONAL SERVICE duce a substantial DC supply capable of operating the electrical starters on the Proteus engines. call be assisted in a number of ways and the SR.N4 will For the operation of the heating and ventilating systems, have many of these fitted as standard, among them being a duct directed into the eye of the lifting fan withdraws air radio communication, radar, Decca navigator equipment from the car deck and, as both the passenger cabins and and other aids. Under normal conditions, approach buoys, control cabin are vented into the car deck, the complete ramp centreline markers, guide lights and radar reflectors craft is ventilated by this source. will be required, various forms of which are curre~itly The craft also has a self-contained bilging system which undergoing evaluation. For night operations the ramp must enables each compartment of the buoyancy tank to be be floodllt as soon as the craft comes to rest to give free bilged independently. movement of passengers and cars without any risk of accident or confusion. Operational Performance A typical hoverport is illustrated, this being of the inter- For routine maintenance the craft can be parked on nat~onaltype with Customs and immigration, although the ground capable of taking loads from the land~ngpads. Tn type shown could be used anywhere where a moderate the case of level ground where all five pads are in contact, frequency of service is expected. The essential feature is the ground pressure would be from about 4.5 tonslsq ft the layout of the aprons and ramps, the inshore part of the to 7 tonslsq ft for the unladen and maximum weights hoverport being arranged to suit whatever type of service respectively. For inspection and maintenance of the bottom is envisaged, It has been estimated that this hoverport area and the skirts, the craft may be lifted by three palrs should be capable of handling the arrival and departure of jacks housed in tubular legs on which the craft can of an SR.N4 every seven minutes (five minutes turn-round stand for indefinite periods. A mobile crane is the only plus two minutes manoeuvring) on a short domestic route, large plece of equipment required for major servicing giving as a peak a potential maximum traffic of 300 cars operations. and 2,500 passengers per hour. On longer ~nternational The SR.W4 has been specifically designed for a rapid routes the turn-round plus manoeuvring time would prob- turn-round as this is particularly important on short routes. ably be up to fifteen minutes, reducing the traffic figures to It is possible for vehicles to drive straight off as soon as 120 cars and 1,000 passengers per hour. the power-operated bow ramp is lowered, while passengers A d~agramillustrating the total thrust and drag acting leave simultaneously by the integral steps on either side of on the craft in still air is reproduced here, showing these the craft. During this time a mobile ramp call be brought quantities plotted against forward speed for the mean up to the wide stern doors, permitting cars to drive on AUW of 147.5 tons. The drag curve is composed of aero- easily and quickly as soon as the deck is clear. dynamic profile drag, the momentum drag of the air enter- Operat~onsin bad weather and during hours of darkness ing the fan intake and the hydrodynamic drag, which been estimated that with the SR.N4 a wave height of up to 6 ft will have very little effect on craft air speed into wind, the reduction in alr speed being about 10%. This is because the higher waves are being negotiated at a lower water speed and thus the hydrodyllarnic drag as well as the aerodynamic drag remains substantially constant. An average service speed of 60 knots is envisaged for cross-Channel operations, and it is confidently predicted by the British Hovercraft Corporation that the SR.N4 will be able to cope with all but the mose extreme conditions met with on these routes. Year-round services will be estab- lished with suspensions in operation on perhaps two or three days a year, when even conventional marine craft will be unable to leave harbour.

BHC AND BELL AEROSYSTEMS FORM ORGANISATlON FOR

On February 14th, 1967, Bell Aerosystems Canada and the British Hovercraft Corporation announced formation of a joint marketing organisation in Canada. James G. Mills, Vice-President and Managing Director of Bell Aerosystems Canada, and Stuart J. Miller, North American Manager for the British Hovercraft Corporation, will direct the co-ordinated market development pro- gramme designed to introduce air cushion vehicles into comrncrcial and Government operations in Canada. "We intend to pay specific attention to the requirements of potential ACV users in Canada," Mills and Miller explained. "Once the market has developed," they con- tinued, "qualified Canadian operating companies will become established." Headquarters of the BAC/BHC organisation are located in the Credit Foncier Building at 199 Ray Street, Toronto, Ontario. Formation of the joint marketing organisation follows two years of preliminary research and several months of THRUST AND DRAG operational trials of hovercraft in various Canadian en- vironments. These operations have ranged from trials of a includes that due to wave and water wetting. l:he last two British SR.N.5 hovercraft in the Tuktoyatuk region of the quantities cause the peak evident in the drag curve at Canadian Arctic to the recently concluded evaluation of a 21 knots, but with further increase in speed the contri- Bell SK-5 at Trenton, Ontario, by the Canadian Depart- bution of the ware drag diminishes, while that of the other ment of Transport. components increases. The thrust is composed of three Performance during these trials has proven that ACVs terms, that from the propeller, from the engine exhaust have the unique ability to traverse any surface, including and due to the cushion jet, and the reduction in total water, land, ice, snow, tundra, muskeg, mud and even thrust seen with the increase in forward speed is due to rivers during ice break-up while carrying heavy payloads the typical fall in propeller thrust. at high speed. Where the thrust and drag curves intersect, the craft is Thus, these vehicles could solve some of Canada's more in equilibrium, and up to this point the difference between difficult transportation problems. The wide range of appli- the curves is a measure of the acceleration which can be cation-; for the craft include transport of supplies and achieved at a given forward speed. The lower of the two equipment to remote sites in Northern Canada for mining, thrust curves shows that produced when the engine is hydro-electric development, water conservation and ex- operating at the maximum continuous rating of 3,400 shp, ploration and survey work, harbour patrol and mainten- this giving a maximum speed at the AUW quoted of 70 ance, air-sea rescue operations, and passenger ferry service. knots. This speed can be increased for a limited duration Bell Aerosystems Canada, a division of Textron Canada of time to 77 knots, but it is not recommended for general Ltd, was formed by 'extron's Bell Aerosystems Company use because of the adverse effects referred to previously. of Buffalo, New York, in October 1966. The estimates refer to skirts 7 ft in length, of the type British Hovercraft Corporation of Yeovil, England, and where the lower type of the skirt is in the form of fingers Bell Aerosystems have been linked by licensing agreements through which the cushion air is directed. since 1963 when the two companies joined forces in an A great deal of data has been collected from existing international programme to promote and develop ACV hovercraft trials and commercial operations regarding ovcr- transportation, wave performance and the frequency with which severe The two companies offer a broad spectrum of air cushion conditions have been met. particularly valuable being the vehicles ranging from a 7-ton ACV capable of carrying 'information on the different kinds of sea state that may be 19 passengers or 6,000 1b payload to a car ferry with a encountered across any particular stretch of water. It has capacity for 30 automobiles and 250 passengers. (Part XIV)

ie Hayward

"Stryela" An anhedral type nose foil has been fitted to improve HIS 92-passenger craft successfully completed its trials stability in open sea conditions. Ladder type foils are fitted T on the Black Sea in the autumn of 1961. Speeds up to both fore and aft, and a surface-skimming foil has been 50 knots were attained. Stryela is similar in appearance to added amidships. Various passenger cabin arrangements Mir, and unlike most of the Russian craft is fitted with have been adopted ; the seagoing craft have sleeping cabins surface-piercing foils. Twin diesels, collectively developing for 100-120 passengers, and the short-haul type carries up 2,400 hp, are arranged to drive twin screws. Fully auto- to 150 passengers. Two 1,100 hp diesel engines drive twin matic control systems are installed and an automatic helms- propellers. This craft was designed and developed by the man inay be locked in on long voyages. shipyards at Sormova but the production craft are built at In June 1962 this craft was put in service between Yalta the Georgia yards on the Black Sea coast. and Sevastopol, the time taken by the normal ferry service Two Kometa craft will be delivered to the USA by the of 69 hours being cut to 1+ hours. Soviet Sudo-import Organisation during 1967. Ko~neta A second craft completed in October 1965 probably craft have already been exported to Western Germany and holds the world's record for a long-distance journey by Bulgaria, and negotiations are proceeding on the sale of a hydrofoil. The journey from Yalta to Leningrad, a distance craft to Greece. of 2,735 m~les,was accomplished in 100 hours' operational time. The craft traversed the Black Sea to the Sea of Azov, the Volga-Don, the Volga and then through a series The Fulgar is a single-seat research and development of interconnecting lakes at Tsimlyansk, Volgograd and craft. Rybinsk to the new Volga-Balt canal, where it passed An interesting feature of this craft is the form of pneu- through Lakes Svir and Onyega to the River Neva. matic insulation provided to deaden wave shock at the In recent months Stryela craft have been operating on stern. Adjustable incidence, "V"-shaped arrow-like foils are scheduled service between Tallinn and Leningrad. fitted, the incidence angle being variable from the cockpit. Fulgar is reported to have reached speeds of 37 knots. "Delphin" Acceptance trials of this 120-150-passenger craft were "Vikhr" completed on the Volga during May 1964. Powered by Probably the largest seagoing hydrofoil craft at present turbo-jet engines, said to be similar to the power units of operating anywhere in the world, Vikhr appears to have the TU.124 aircraft, Delphin is the first passenger-carrying, been developed from the Sputnik class of craft. gas-turbine-engined hydrofoil craft produced in Russia. The hull, of lightweight construction built up by welding, Length overall ...... 1 57 ft 0 in is very streamlined in shape. A system of water-jet reaction Breadth overall ...... 29 ft 6 in is used for propulsion instead of the orthodox propellers. Total displacement ...... 110 tons Speed of the Delphin is reputed to be in the range of 68- Maximum speed ...... 25 knots Cruising speed ...... 43 kllots 70 knots. Passenger capacity ...... 300 persons

"Kometa" Built at the Sormovo yards and launched during 1962, Very similar in construction and appearance to the scheduled services have been carried out between Odessa Meteor craft, Kometa was launched in the late autumn of and Crimea resorts and Odessa and Yalta. Four 1,200 hp 1961. Extensive trials and minor modifications were carried diesel engines power four water propellers for propulsion, out before this craft was put in regular service on the the propellers being supported by stern struts attached to Black Sea in the spring of 1962. the underside of the rear of the hull. The front and rear foils are of "V" shape and are also swept backwards. An Length overall ...... 115fLOin amidships foil assists in attaining longitudinal stability. Breadth overall ...... 31 ft 6 in Maximum draught : Pull displacement role ... 10 ft 6 in "Chaika" When on foils ...... 4ft8in Developed by the Krasnoye Sormovo shipyards at Gorki, Total displacement ...... 58 tons the experimental Chaika has been used to test a water-jet Maximum speed ...... 40 knots '# Cruising speed ...... 34 knots propulsion system likely to be used in larger Russian craft Passenger capacity ...... 150 persons now under construction. ...",

Figure 98. Sketch of the general luyout of the "Chaikci"

Length overall ...... 86 ft 3 in rnanoeuvrab~lity and docklng operations. Var~ableinci- Breadth overall ...... 12ft 6i11 dence, fully submerged, t~taniumfo~ls are fitted at the bows Maximum draught : and stern, the folk belng protected by outr~ggerplatforms i Full displacement: role . . . 3 ft 10 in Wheilonfoils ...... Ift Oin whlch also serve as service platforms. Total displacement . . . . . 14.3 tons Maximum speed . . . . . 60 knots Cruising speed ...... 46.5knots Length overall 142fl 0111 Passcliger capacity ...... 30 persons Brcadth overall 22ft O ln Range ...... 3lOmiles Maximum draught Full displdcement role Sft loin A 1,200 hp diesel engine drives a two-stage pump pro- When on folls I ft 41n (0 Total displacemeiit 62 tons viding water-jet propulsion. Rudders on each side of the Max~murn speed SO knots water-jet nozzle provide directional control. Hull design Cruising speed . 65 knots and compartmentation are similar to that used for Sputnik. Passenger capacrty 1 SO persons A full description of this craft was given in Vol 3 No 9 of Hovering Craft & Hydrofoil, June 1964. General Considerable research actlvlty on varlous types of hydro- Claimed by the Russ~ansas belng technically and opera- foil craft 1s belng undertal

Figure 99. "Chuika" Figure 100. "13ureve.stnik"

POLAND The Zryw-I has two shallow submerged stainless steel Tn 1961 the Department of Naval Architecture of the foils with a longitudinal and transverse dihedral in a tan- Gdansk Techn~calUnlvers~ty wds consulted by the Pollsh dem system. The front foil is of thc surface-piercing type Central Board of Inland Navigat~onand R~verShipyards and the rear foil is fully submerged. The light alloy hull is concerning the dcs~gnof a hydrofoil craft for operation In of almost fully welded construction, riveting being applied the F~rthof Szczecin The Zryw craft bu~ltdurlng 1964-65 only for the jolnts of the framlngs wlth the outer plating by Gdansk River Sh~pyardwas the result of thls collabora- of the roof, partii~onwalls and for loln~ngsteel and light tlO11. alloy elements. A Russian dlesel englne of 1,200 hp IS used to drive the Length overall ...... 90ft6)in three-blade water propeller. This craft has been in service Breadth overall ...... 22ft Oin Maximum draught : on the S~czec~~~-Sw~noujsc~eroute, the forty-one mlles Full displacement role ... 6 ft 9 in being covered In approximately fifty-five mlnutes When on foils ...... 4 ft 1 in Total displacement ...... 30.7 tons Maximum speed ...... 45 knots Cruising speed ...... 35 knots Paasengcr capacity ...... 76 persons all you need to know to UNDERSTAND COMPUTERS A book, 'The Computer and Your Company9, written specially for men in industry

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