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Home , Margaret Rule, Mary Rose

Underwater Technology

Based on a paper presented at an SUT International Conference on Man-made Objects on the Sea Floor, held 1/2 February 1995, London. See p.3? for areport on the conference The Raising of the : Archaeology and Salvage Combined

by C. T. C. DOBBS*

Abstract the next seven years the outline ofthe was revealed The Mary Rose was buiIt between 1509 and 1511 and as they excavated around the ship to expose the was a highly successful warship until she capsized and structure. Excavation was purposely confined to areas sank in in 1uly 1545. In 1982, after many outside the hull until a dear picture was obtained years of painstaking search and investigation, the of how the ship was lying on the sea bed. It was not M ary Rose was recovered from the sea bed with until 1978 that a major trench was excavated across unprecedented interest and support from the public. the ship, in the bow area. This not only revealed that In this paper, some of the problems associated with many of the personal possessions of the crew and ship's raising a fragile structure which also has great stores had been preserved in situ, but also that the archaeological and historical importance are described, surviving hull was indeed a coherent structure and and aspects of the salvage programme are given from that it might weIl be possible to salvage her. the perspective of one of the archaeological divers The major excavation of the hull was carried out involved with the raising of the Mary Rose. Finally, in the four main diving seasons of 1979 to 1982 and the importance of integrating the professions of both revealed a fascinating cross section of artefacts from salvage and archaeology in such an operation is a Tudor ship, many of which are on display at the illustra ted. Mary Rose Exhibition in . The story of the search, discovery, and excavation has been covered Introduction in a number of books (Bradford, 1982; McKee, 1982; The Mary Rose was built in Portsmouth between 1509 Rule, 1982; Rule, 1983b for salvage). More recent and 1511 and served in Henry vm's Navy for 34 years work in the ship hall has been summarised elsewhere before sinking in the Solent on luly 19th 1545. Soon (Dobbs et al., 1990; Dobbs, 1994) and this article will after, contemporary salvage attempts failed and she concentrate on certain aspects oft he salvage operations. was abandoned. AIthough a number of items including A further aspect of the project that will be of guns were recovered during these attempts and again particular interest to members of the SUT concerns in the 1830s when the pioneer heImet divers lohn and the large amount of 'high-tech' equipment used or Charles Deane carried out some further salvage, she tested on the Mary Rose site at various stages in the was otherwise left alone until 1965 when Alexander investigations. This was part of a far-sighted policy by McKee initiated the modern attempts to find her. His the Archaeological Director, , that 'Project Solent Ships' aimed to investigate a number ensured that the cutting edge of technology was used of the historic wrecks in the Solent, and from 1966 wherever possible to develop the techniques of remote sensing techniques were used to augment the . Whilst some of these items diver searches in the area where he suspected that the such as video cameras are in common use nowadays Mary Rose lay buried. on scientific projects, this was not the case in the 1970s In 1967 and 1968 a combination of sidescan when many were only just being made more widely and sub-bottom profiler was tried and this recorded available. It is beyond the scope of this artide to an anomaly that led to the identification of the site. describe them in great detail and more information is This vital work was carried out by Professor Harold available in Rule (1983) and Clark (1981), but they Edgerton of the Massachusetts Institute of Technology included the following items. and lohn Mills and was a great encouragement for Video was used extensivelyon the project both to the . It also stimulated the formation of record aspects of ship structure and to help with the The Mary Rose (1967) Committee to co-ordinate work training and briefing of the amateur divers. Marconi on the site with Margaret Rule as Archaeological Avionics loaned their equipment-initially the 'Blue- Director and Alexander McKee as Director of ball', black and white video camera and this was later Excavations. However, as the ship was still buried, a augmented by a colour system. The low-light capability great deal more patient work was needed before the of this camera was of great benefit in the murky water timbers could be seen. of the Solent and another advantage of video is the In 1971, archaeologists and divers caught their first ease with which a simple tracking shot could be used glimpse of a few frames of the ship. Gradually over to show the re1ationships between parts of the structure that could not be illustrated using a static *M ary Rose Trust, College Road, H M N aval Base, Portsmouth, shot. As the video cameras were linked to the surface POl3LX by umbilical, live views of the work in progress on the

29 Volume 21 Number I Underwater Techoology

seabed could be seen on the salvage vessel and, on were discussed at two meetings, specially convened by special occasions, these were relayed to the public the Mary Rose (1967) Committee. gaHeries at Castle via a microwave link that One considered the first question, and was attended had been set up by the late Jim Clark at British by archaeologists, ship historians, naval architects and Airways. During the salvage operations, an ROV museologists, who considered the archaeological provided by Comex Houlder was also deployed on evidence and the historical importance of the ship in the site. Stereo video was also used, as was a sonic cultural, social and military terms. They agreed that camera, but the lack of a large database to assist with the M ary Rose should be completely excavated and the interpretation of results meant that the sonic recorded as she lay on the sea bed. They also agreed camera could not be used to its fuH potential. Whilst that if this was feasible, the hull itself should be sidescan sonar had first been used on the site in 1967, recovered and brought ashore to form the centre-piece a stereo sidescan system was used in 1978 and a sector of a Tudor Ship Museum. scanning sonar was demonstrated in 1981. This latter The second meeting was attended by salvage system was tested for its potential for monitoring consultants, salvage contractors, structural engineers divers underwater, but on our particular site there was and naval architects who agreed that it should indeed too much 'background noise' from the compressed air be possible to reinforce and recover the hull, although system supplying the airlifts. this could only be confirmed after the ship had been In certain conditions, surveys were greatly assisted emptied and surveyed in greater detail. by the use of through-water communications for the As a of these two meetings, a charitable divers on scuba, whilst during the salvage operations company, the M ary Rose Trust, was formed in January this was not needed as the diving team then had the 1979 with objectives that included: 'To find, to record, benefit of the hard wire communications of the SODE to excavate, raise, bring ashore, preserve, publish, (Surface Demand ) system. The report on and display for all time in Portsmouth, the accuracy of measurements taken over larger distances Mary Rose.'.(Rule1982b, 1983). was assured by using a rangemeter developed by John Although the original aim was ro raise the hull if Partridge in surveys undertaken by Nigel Kelland of at all possible, the final decision to go ahead with the Sonardyne. He and David Lawes of Sonardyne also salvage operation was not taken until January 1982 provided the sonar docking system that was installed when all the necessary information to make the to monitor the transfer of the hull and lifting frame decision was available. Even after that date there were from their original position to dock with the lifting various 'cut-off dates' when the decision to halt, cradle. survey and backfill could still be taken. As the excavation became deeper, the need for a All salvage operations present their own particular user-friendly, three-dimensional survey method became set of problems but an important factor in trying to apparent as traditional methods such as using a plumb salvage the Mary Rose was that the remaining hull bob to position the horizontal measurements and was an open shell, consisting mainly of the starboard measure the depth below datum were not appropriate side of the hull, rather than a complete cross section given the problems with visibility and currents. A with transverse strength. Many salvage methods were was provided by Nick Rule who developed considered and the Trust had the benefit of expert a survey method and corresponding computer pro- advice from an Advisory Committee under the gramme that was fast, simple and accurate and also chairmanship of Professor G. Goodrich. The problem enabled errors to be quantified (Rule, N., 1989). of the open shell led to an important decision being Named th~ Direct Survey Method or DSM, the taken: namely to carry out the lifting operation in three technique allowed slant measurements to be taken very distinct stages. direct to die objects from the known datum points, In the first stage, the problem of 'bottom suction' rat her than requiring horizontal and vertical measure- had to be overcome. This was achieved by raising the ments. The programme has been further developed first few centimetres over aperiod of several days using since the original work on the Mary Rose and is now an ingenious system of twelve hydraulic jacks which in use on many underwater sites worldwide. raised the lifting frame slowly up the four legs (Fig. la). It was only when the hull was hanging freely Aspects of the salvage operations from the lifting frame, clear of the sea bed and the The decision on whether or not to salvage the hull of suction effect of the surrounding mud, that the salvage a historic ship is not an easy one to make. Due progressed to the second stage when the hull was lifted consideration has to be given to so many different completely clear of the sea bed and transferred factors, varying from whether it is technically and underwater into the lifting cradle (Fig. 1b). economically feasible to whether the funding can be For this lifting operation the giant floating crane sustained for the long-term restoration and con- Tog Mor was the ideal vessel as the 'Stielcken derrick' servation programmes that are required after salvage. enabled it to position the hook and the load very The 1978 excavation showed that salvage might be accurately without the need for continually adjusting possible. Two major questions then had to be the four point mooring system. The third and final answered. Was it desirable to carry out a full stage was to lift the entire structure into air, by excavation of the ship and her contents and then which time the hull would also be supported from raise her? Secondly, was this feasible? These questions below (Fig. lc). This would ensure maximum support

Summer 1995 30 Underwater Technology

Fig. Ja The hu/l is wired up to the lifting frame from the bolt positions. Hydraulic jaeks, operating on the legs of the frame, then raised the hu/l those first eritieal centimetres until it was free of the 'suction' effeet of the silts below

Fig. Jb The hull, hanging from the lifting frame, could now be transferred underwater into the support cradle. This required precise positioning to loeate the legs of the frame into the four 'stabbing guides' of the cradle. The eradle had been built to conform to the shape of the hull using the section drawings produeed from the arehaeologieal surveys

Fig. Je The hull is safely in the eradle and is ready for the finallifi into air supported from both below and above. Additional eushioning for the hu/l is provided by a series of air bags positioned between the hull and the cradle. The lifiing frame now acts as aspreader for the wire straps from the crane hook

31 Volume 21 Number 1 Underwater Technology

2 Gun Pon urround

o Main Beam- helr ______Ortop Iringer

Orlop Deck Beam- helr

Diagonal Brace

_--- l:Iold Iringer

lUder

, eclion 2'

Fig. 2 The bolt positions in the bows of the' Mary Rose'

for that crucial period at the interface between the location of the salvage bolts to distribute the water and air. equally. As late as June 1982, a change to the method of The actual bolt positions that were chosen in each stropping was proposed when it was decided to lift of these areas can best be illustrated by referring to the hull with a network of bolts and internal lifting Figure 2 which shows the bolt positions in the bow. wires rather than use the more traditional salvage Looking along 'Section 2' we can see a typical method ofusing external strops (Rule, 1983b: 217). The sequence of the structural elements chosen as the advantage of this method was that the loading of the strong points of each section. There were exceptions !ift could be spread much more evenly over the entire to this pa ttern but the rationale of selection was similar structure of the hull and the need for heavy stiffening in each area. inside the hull was avoided. There were disadvantages in changing the method Each of the 67 main lifting points consisted of a of salvage in the light of the new programme of work bolt passed through the hull and, when tightened down that was now required. Every single lifting point had onto the internal and external spreader plates, these to be individually located and drilled, the bolt placed in bolts also acted as clamps to the hull firmly position, the hull undercut to enable the backing plate together. One hundred and three further bolts were to be fitted, and the bolts tightened up. Figure 3 and fitted to act as additional clamps. In many areas of the associated captions illustrate this new sequence of the ship these were merely an additional safety factor tasks required for attaching the hull to the lifting frame. as the original treenails were still extremely firm, The M ary Rose Trust's team were but in the weaker areas such as at the bow, the weIl qualified to do this work as they were not only sterncastle and along the eroded port side, the extra fully qualified to use the commercial equipment and strength given by the clamps was vital for holding the procedures that made the work effective and safe, but component timbers together. also included individuals who were graduate archae- The decision on where the clamps and lifting ologists or engineers, surveyors and other pro- points should be located is based on the way in fessionals. In addition they had thousands of hours which the ship is constructed. The length of the experience on the site and an intimate knowledge of hull can be considered in terms of 12 areas. In eight the hull. of these areas, the riders fitted into the hold of The schedule to complete this new work programme the ship during a rebuild in the 1530s were still in was very tight and the availability of a surface piace and these riders, coupled with ten diagonal and supplied diving system was vital to the success of the vertical braces, acted as further important points for work. The benefit of an unlimited air supply and the

Summer 1995 32 Underwater Technology

Fig. 3a At eaeh seetion of the hul/, the key structural timbers to take the salvage bolts IIwe identified and the bolt positions were marked with tags (see arro\Vs). The holes ,•.ere then dri/led using an Atlas Copco pneumatic . Special bits over 1500 mm long had to be manufaetured for the longest bolt holes. Accurate drilling in the very lo\V visibility required great patience and skil/.

Fig. 3b As each seetion was eonnected up to the lifting frame, divers could Ihen dig furlher under the hul/ 10 locate the nexl bolt positions. This work was carried out using Ihe combinalion of a \Vaterjet to eut through the hard c/ay and a 6 inch airlift to extract the spoi/. Steel rods plaeed in the bolt holes helped divers to loeate the neXI area by feet.

use of surface deeompression meant that dive times need to be jetted away to expose the next bolt eould be extended and speeific tasks eould be completed position. in each dive. Time not spent underwater or on standby Another erueial advantage of adopting the internal was used on the assoeiated tasks of tending divers, wire method of stropping was that the wires were also running the surfaee demand dives or ehamber de- used to monitor the even lifting of the hull during the eompression sehedules, and making up eaeh of the first few eentimetres out of the mud. If the wires on baeking plate assemblies on the deek of the salvage one side went bar tight and on the other side went platform Sleipner. slack, the jaeking eould be adjusted to even out the After the baeking plates were fitted and tightened, lift. Additional monitoring was provided by 'tell tales' the exaet distanees were measured from the eyebolts eonsisting of plastie tags attaehed to either side of inside the huH to the eyes on the lifting frame above. important joints in the huH. The wires could then be made up to the eorreet length The jaeking lift and subsequent underwater transfer by the diving team and taken down for fitting (Fig. 3d). were erueial to the sueeess of the salvage and it was Onee eaeh seetion of the huH was wired up to always assumed that these would be the triekiest parts the lifting frame, the huH was undereut to loeate of the operation. Indeed there were problems both the next row of baeking plate positions. In this way with these two stages and with the final lift into air, the divers never had to work underneath areas of the but fortunately all these problems had their own huH that were not held up from above. Further safety individual . On one of my dives before the was provided by the baulks of clay that remained final salvage, I went down with Margaret Rule to supporting the hull from below and which did not inspeet the ship and we eould feel the hull gently

33 Volume 21 Number 1 Underwater Technology

Fig. 3c Fitting the bolt and backing plate assemblies and tightening the bolts was a two person task. However they could easily co-ordinate this work through the surface as their heimets had excel/ent voice communications. A typical backing plate consisted of a 600 mm square sandwich of lIVo types of expanded foam backed by 7-ply marine timber and heavy channel bar. For some locations, backing plates were specially prepared to shape.

Fig. 3d The final part of the programme was to fltthe wires between selected bolts and the liftingframe above the hul/. Each wire was made to the specific length required and equaltensioning throughout the hul/ was achieved wiChthe bottle screw on each wire. (Drawings by J. Adams

swaying on the salvage wires from the lifting frame. project through to the phase of 'active conservation', From that moment we knew that salvage was which started in September 1994, confirms that it has feasible, although not yet completed (Rule, 1983a). also been a successful project. In retrospect, the story of the salvage is filled with However it must be realised that the decision to similar moments of relief, moments of great tension, salvage, or even excavate a wreck of archaeological and finally moments of elation when the hull was or historical importance, is a very bold one and should towed into in the evening of only be taken after the most searching studies of the October 11th 1982. The tumultuous welcome was consequences have been made. All the necessary quite overwhelming and after the exhaustion of the recording and conservation work takes a tremendous previous months, it was only when confronted with amount oftime and money and the decision to uncover these crowds that the diving teams fully realised the or recover objects on the sea floOf must be taken with importance of the feat that had been achieved by a full awareness of these responsibilities. combination of diving, archaeology, engineering and technology. The fragile but substantial remains of a Acknowledgements Tudor warship had been salvaged successfully after The successful raising of the Mary Rose was, above 437 years on the sea bed (Fig. 4). all else, a team effort. It could not have been accomplished without the dedication of an enormous Discussion number of companies and individuals and it would The excavation and raising ofthe Mary Rose was quite not be possible to list them all. However, I would an achievement of archaeology and engineering by particularly like to acknowledge the following: The any standards and the continued development of the Advisory Committee on Recovery, chaired by Professor

Summer 1995 34 Underwater Technology

Fig.4 The 'Mary Rose' 's finally raised, supported (rom below by the steel 'ifting cradle

G. Goodrich; Nigel Kelland of Sonardyne: the late 2. Clark, J. 1981. Mary Rose-electronic systems, in Jim Clark of British Airways; John Grace of R. J. J. Shand (ed.), Progress in Underwater Science, 6, Crocker; Bill Summers of Bygwik Telford; Captain 72. John Suddes and Captain John Gray of Howard 3. Dobbs, C. T. c., Rule, M. H. and Jones, A. M. 1990. Marine; Captain Arthur King of Alexander Towing; 'The Excavation, Salvage and Recovery, and John Higginson of Comex Houlder, now Stolt Comex Passive Conservation of the Tudor Warship Mary Seaway, and the major efforts of the R.E.D.E. Diving Rose', Paper given at 11 Curso de Arquitectura Team. Naval, Siglos XIV al XVIII 'Quinto Centenario', Former members of staff at the Madrid, December 1990. whose input must be acknowledged inc1ude: Colonel 4. Dobbs, C. T. C. 1994. Recent Work on the Hull Wendell Lewis, Director of Salvage and Recovery; of the Mary Rose. World Ship Review, 4, 7-8. Dr Margaret Rule, Deputy Executive Director with 5. Rule, M. H. 1982.The Mary Rose. The Excavation Executive Responsibility for Recovery; Adrian Barak; and Raising of Henry VIII's flagship, Conway Jonathan Adams and Christopher Underwood the Maritime Press, London. Co-Superintendents of the Salvage Diving Team and 6. Rule, M. H. 1983a. Henry VIII's Lost Warship. the team itself; and Andrew Fielding, Deputy Director National Geographie, May 1983, 163(5), pp. 646- of Archaeology, whose section surveys were a crucial 675. aspect of the salvage method and the cradle design. 7. Rule, M. H. 1983b. The Mary Rose. The excavation I am also grateful to Mr Adams for permission to and Raising of Henry VIII's flagship, Second reproduce his drawings that illustrate the sequence of Edition 1983, Conway Maritime Press, London. drilling, tunnelling, bolting and rigging and to Debbie 240 pp. Fox for her work on the original isometrie drawings. 8. Rule, N. 1989. The Direct Survey Method (DSM) Although the scope of this artic1e had to be restricted of Underwater Survey, and its Application Under- to just a few aspects of the salvage operations, any water'. International Journal 01 Nautical Arehaeology omissions and errors are entirely the responsibility and Underwater Exploration, 18(2), pp. 157-162. of the author. 9. McKee, A. 1982. How We Found the Mary Rose, Souvenir Press, London. References 1. Bradford, E. 1982. The Story of the Mary Rose, Hamish Hamilton, London.

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