01/10/2010 an Evaluation of the Recovery, Conservation And
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Written: 01/10/2010 An Evaluation of the Recovery, Conservation and Display of the Mary Rose Alan White Abstract The following paper will evaluate the methods used to recover, conserve and display the hull of the Mary Rose. The methods used to recover the many varied artefacts will not be covered, but their conservation and display will be evaluated albeit in less detail than for the hull. Conservation is a complicated scientific procedure and only the basic methods used will be covered in this paper. The current and future museums will also be discussed and evaluated. Keywords Mary Rose, conservation, recovery, museum Introduction The sinking of the Mary Rose The Mary Rose, named after Henry VIII's sister, Mary Tudor (Rule, 1986: 3) was built in Portsmouth between 1509 and 1511, and rebuilt in 1536 (Rule, 1982: 22-28). On the 19th of July 1545 as part of an English fleet opposing a French attack, she sank in the Solent near to the entrance of Portsmouth Harbour, Hampshire, England. Netting placed over the deck caused nearly the entire crew to perish, with reports of losses varying between 400 and 700 hundred lives (Dobbs, 2007: 1). The reason for her sinking is unknown, but may have simply been due to mishandling causing water to enter her gun-ports (Martin, 1987: 142). Early attempts at recovery were abandoned and she slowly sank into the silts of the Solent (McKee, 1982: 36). Tides, weather, bacteria and worm attack took their toll on the exposed section of the ship. The remaining section of the hull and artefacts were preserved in the silts of the Solent, leaving a 'time capsule' of life on board a Tudor warship (Martin, 1987: 142, Lister 2005: 81 and 86). The Mary Rose Trust In 1966 diver Alexander McKee made a chance discovery of the position of the Mary Rose on an 1841 chart (Marsden, 2003: 29, McKee, 1982: 54). A number of years of tireless work resulted in the formation of the Mary Rose Trust, with the aim “to find, to record, to excavate, raise, bring ashore, preserve, report on and display for all time in Portsmouth, the Mary Rose”. In 1982 the hull was recovered and was witnessed by 60 million television viewers worldwide (Dobbs, 2007: 1, Lewis 2003: 51-59, Gaimster, 2003). The Mary Rose now rests in the Historic Dockyard, Portsmouth along with some 19,000 recovered artefacts, many of which can be seen in the Mary Rose Museum (Harrison, 2003: 63). Raising the Mary Rose Earlier attempts at recovery The first attempts at raising the Mary Rose were carried out in the August, soon after her sinking. It appears she was so deeply embedded in the silt that an attempt to upright her had only succeeded in breaking a mast. On the 16th June 1836 the diver John Deane working with his brother Charles Written: 01/10/2010 discovered the wreck while removing snagged fishing nets, a number of artefacts were recovered. Although believed by many to have been destroyed, Alexander McKee led a team of divers in a new search for the wreck in 1965, resulting in her rediscovery in May 1971 by diver Percy Ackland (McKee, 1982: 34-42, Dobbs, 2007: 1, Martin, 1987: 142). The difficulties of recovery During the course of the excavations the decision was taken to recover the hull, this task was fraught with difficulties, due to the fragile and complex nature of the structure. When in the water the ship weighed approximately 45 tonnes but would weigh maybe six or seven times this when out of the water. Therefore there was a strong possibility that the hull would collapse under its own weight when lifted from the sea (Lewis, 2003: 51, Rule, 1982: 202). The only recovery previously carried out on this scale was of the 17th century Swedish warship the Vasa, which was virtually complete and sitting upright in calm water in Stockholm Harbour, Sweden. The Vasa was raised using steel cables and pontoons, then moved into shallower water where she was excavated, the process took twenty months to complete (Franzen, 1961: 14-18, Bass, 1966: 63-66). In comparison only about a third of the Mary Rose remained, in a fragile condition and lying on her side (Lewis, 2003: 51, Rule, 1982: 202-205). Once exposed on the seabed the Mary Rose would be open to attack from micro-organism (aerobic bacteria, fungi etc.), macro-organism (wood borers) (Lewis, 2003: 51, Jones (ed.), 2003: 28-32) The lifting plan and recovery There were number of proposals put forward on how the hull and contents could be raised, these fell into two main categories. The hull, complete with its contents could be transferred to a wet dock then emptied, the other option was to excavate in situ and then move the hull to a land site. The option chosen was to empty the hull of its contents, stiffen it with steel braces and frames then lift it using nylon strops. On reaching the surface, the hull would be pumped out then transferred onto a steel support cradle on a barge for transporting to the shore (Lewis, 2003: 52, Rule, 1982: 210-212). In mid-1982 the lifting plan was revised in favour of lifting the ship from the seabed using an underwater lifting frame (ULF). The hull and the ULF would be transferred whilst under the water onto a cradle lined with air bags. The entire arrangement would then be lifted to the surface, placed onto a barge then transferred to a dry dock. The decision to revise the lifting plan at such a late stage increased an already large workload (Dobbs, 2007: 3-4, Lewis, 2003: 53-54, Rule, 1982: 216). Suction on the seabed had been a concern when raising the Vasa and the same problem afflicted the Mary Rose (Franzen, 1961: 72). Undercutting of the hull to position salvage bolts had alleviated some of the problem, and a “peeling” technique would be used when lifting (Dobbs, 2007: 2, Lewis, 2003: 56). Decking planks, cabins and bulkheads were removed for safety reasons from the hull before recovery (Rule, 1986: 5). On the 29th September 1982 everything was in place and around midnight on the 30th September lifting commenced. Once removed from the seabed the hull was transferred under the water, ready for lifting a week later, the time lapse was to avoid the spring tides. It was discovered when docking the ULF into the cradle that one of the legs had been bent. This was probably caused by the leg not clearing the seabed when transferring, after some debate the offending leg was removed. On reaching the surface it was noticed that the south-east lifting sling had been incorrectly positioned, this resulted in a sudden slippage, and fortunately no damage occurred. Once on board the barge a new leg was welded into place and the Mary Rose was towed into Portsmouth Harbour after 437 Written: 01/10/2010 years at sea. Having hovered near disaster the hull was transferred to a dry dock, this successfully completed the enormous and difficult task of recovery (Lewis, 2003: 54-59, Rule, 1986: 6-7). Errors had occurred during the task of recovery, but the job had been carried out in poor visibility and some difficult decisions. Fortunately the steel ropes and shackles used withstood the extra stresses put on them; this episode highlighted the importance of good quality equipment (Lewis, 2003: 57-58). The project had coped with the loss of experienced divers due to the Falklands War, increased workloads and poor weather. The task of recovering the Mary Rose had been pioneering, the success of which was mainly due to an almost national effort and the flexibility and innovation of the lifting plan. The importance of a good underwater survey cannot be underestimated, this had allowed the structural engineers to successfully design the lifting frame and cradle. The Mary Rose had arrived at dry dock undamaged and could now be conserved (Rule, 1986: 7). Conservation of the Mary Rose hull and artefacts Site geology and preservation The Eocene clays in which the Mary Rose sank had contributed to her preservation; these sediments provided oxygen free (anaerobic) conditions that protected her from micro-organisms and macro- organisms. If the ship had sunk onto the nearby flint gravels it is unlikely that she would have survived (Cronyn, 1990: 15, Jones (ed.), 2003: 22-27, Collins and Mallinson, 2003: 71-75) The reasons for conservation Reversibility is a desired effect of any conservation process, this is in the event that a new process emerges or additional conservation is required. Organic material such as rope, wood, textile, and leather can crumble to dust in a matter of a few hours if not conserved. Iron can last a few days or months according to size and density and bone, glass and pottery slowly de-vitrify if not conserved (Hamilton, 2000). Conservation should begin as early as possible and some protection of the Mary Rose was provided on the seabed by covering the hull in plastic sheeting during seasonal breaks in excavation (Jones (ed.), 2003: 31). Each recovered artefact was catalogued and recorded, then 'first aid' was applied before carefully packing and transferring to shore (Rule, 1986: 12). It was of great importance that a plan was in place for the conservation of the hull and the artefacts that were recovered from the Mary Rose (Hamilton, 2000). It was decided to tackle this problem in conjunction with Portsmouth City Museum (Rule, 1982: 89-93). Once on dry land bacteria and worm damage of the hull and wooden artefacts would occur within a short time, some recovered timbers and wooden artefacts were stored in a pond or wrapped in polyethylene sheeting (Jones (ed.), 2003: 32-40).