The Raising of the Mary Rose: Archaeology & Salvage Combined - Page 2 of 8

All salvage operations present their own particular set of problems but an important factor in trying to salvage the Mary Rose was that the remaining hull was an open shell, consisting mainly of the starboard side of the hull, rather than a complete cross section with transverse strength. Many methods were considered and the Trust had the benefit of expert advice from an Advisory Committee under the chairmanship of Professor G. Goodrich. The problem of the open shell led to an important decision being taken: namely to carry out the lifting operation in three very distinct stages.

In the first stage, the problem of 'bottom suction' had to be overcome. This was achieved by raising the first few centimetres over a period of several days using an ingenious system of twelve hydraulic jacks which raised the lifting frame slowly up the four legs. It was only when the hull was hanging freely from the lifting frame, clear of the sea bed and the suction effect of the surrounding mud, that the salvage progressed to the second stage when the hull was lifted completely clear of the sea bed and transferred underwater into the lifting cradle (fig. 1b).

Model of the Lifting Cradle

For this lifting operation the giant floating crane Tog Mor was the ideal vessel as the 'Stielcken derrick' enabled it to position the hook and the load very accurately without the need for continually adjusting the four point mooring system.

The third and final stage was to lift the entire structure into air, by which time the hull would also be supported from below (fig. 1c). This would ensure maximum support for that crucial period at the interface between water and air.

Tog Mor

As late as June 1982, a change to the method of stropping was proposed when it was decided to lift the hull with a network of bolts and internal lifting wires rather than use the more traditional salvage method of using external strops (Rule, 1983: 217). The advantage of this method was that the loading of the lift could be spread much more evenly over the entire structure of the hull and the need for heavy stiffening inside the hull was avoided. Each of the 67 main lifting points consisted of a bolt passed through the hull and, when tightened down onto the internal and external spreader plates, these bolts also acted as clamps to hold the hull firmly together.

 

Back to top