The Mary Rose is the only 16th century ship on display in the world. It was once the flagship of Henry VIII’s fleet but sank in 1545 during the battle of Solent with the French invasion fleet.
The circumstances of the wreckage are not well known, as there are three different versions of the story. The French tought they had sank the ship during a fight at dawn, however, there is no archaeological evidence to support this theory. They were firing on the ship, so it was normal to think that they sank it. The second version comes from one of the 25 or 30 survivors of the wreckage. He states that the ship sank because the gunports were left open when executing an abrupt turn. One last version states that indiscipline among the crew members sank the ship. The most accepted theory is the second one, although there is no direct evidence of that fact.
The wreck was discovered in 1965 but was excavated in 1982 using a sophisticated technique of lifting the Mary Rose on a cradle and solidifying it before rising above the water. Along with the hull of the ship, divers have recovered 20571 artifacts from the site. However, there are still many pieces of the ship underwater. It is planned that the stempost and an anchor will be recovered in october 2005.
But you might ask, why does it make the news right now?
A team led by swedish scientist Magnus Sandström showed that the accumulation of sulphur causes conservation problem because when exposed to oxygen (such as rust attacking the nails or other iron parts), the sulphur transforms itself into sulphuric acid. It then attacks the wood in a fairly severe manner.
Using earlier reports, 2 tons of sulphur has been found in the wood itself, posing a great threat to preservation of the hull. The team studied the ship using a synchrotron X-ray beam from Stanford Synchrotron Radiation Laboratory in collaboratio nwith the European Synchrotron Radiation Facility. The results of this study has been published today.
The Mary Rose Trust, which is behind the preservation of the ship, has begun a new phase of the treatment to slow the growth of acid in the wood. For slowing down the organo-sulphur oxidation reaction and prevent new acid formation, wood samples from the Mary Rose are being treated with antioxidants in combination with low and high grade polyethylene glycol (PEG). Another approach to slow down acid formation in PEG treated conserved archaeological wood is to maintain it in a stable climate. It is hoped that keeping a constant low humidity of 50-55% without variations of temperature will stop changes in sulphur speciation. To maintain a stable microclimate within the wood structure a surface coating offers a possible solution, although the effectiveness of this approach has yet to be tested. “This ongoing research is considered to be an important step forward in devising improvements to the current Mary Rose hull treatment programme”, explains Mark Jones, curator of the Mary Rose.
For complementary information, visit the original press release.
Reference: Magnus Sandström, Farideh Jalilehvand, Emiliana Damian, Yvonne Fors, Ulrik Gelius, Mark Jones and Murielle Salomé. Sulphur accumulation in the timbers of King Henry VIII’s warship Mary Rose: a pathway in the sulphur cycle of conservation concern, PNAS, Proc. Natl. Acad. Sci. USA published 26 September 2005, 10.1073/pnas.0504490102. Link to abstract and Full text (Suscription might be required for the full text)
September 27th, 2005 | General Science | No comments
