Time and its effect on the Mary Rose

The starboard side of the hull was protected from shipworm and gribble by the ‘blanket’ of organic rich silts of the seabed which cut off the oxygen, creating an anaerobic environment in which sea creatures couldn’t live and stopped the erosion of the tides and currents. But some bacteria can live in places without oxygen. These bacteria ate away at microscopic parts of the cells of the wood leaving only a sort of skeleton structure which then sea water filled.

When the Mary Rose was rediscovered in the 1970s the starboard side was under a metre to a metre and a half of silt and only four timbers were protruding from the seabed. Divers had to carefully remove the silt from above and inside of the hull.

The hull was raised in October 1982 on a special cradle and floated on a barge into HM Naval Base Portsmouth where she remains today.

Water was sprayed onto the ship to keep it wet for 10 years to desalinate the wood and to allow conservators and scientists to finalise the treatment plan.

After research and testing it was decided that the best way to preserve the hull was to use a waxy polymer called polyethylene glycol  (PEG) to fill the microscopic voids in the wood. Spraying PEG onto the hull started in 1994 and finished in 2013. After spraying with PEG the wood had to be carefully dried out, so large fabric ducts that supplied conditioned air to all parts of the ship were put in place. After three years of slow air drying, the ducts were removed. In 2016, after 34 years, the major conservation treatment of the Mary Rose was complete, and the ship was dry again.

The room where the hull is kept, the ship hall, still has air conditioning because if the temperature or humidity are too low or high, this can cause the wood to deteriorate. If, for example the humidity is too high, mould can start to grow and if the humidity is too low, the wood could dry out too much and split or crack.

There are a few ways we monitor the hull to make sure it isn’t changing over time. If you look carefully in the ship hall you will see what looks like a camera on a big pole; this is called a Total Station, and it automatically takes measurements of different points on the hull three times a day. We also measure small crack markers on the hull once a year to see if they have grown or shrunk, they look like small flags on both sides of a crack. In the summer each year we also remove dust from the hull using special hoovers, this can take two to three months.

We preserve and protect the Mary Rose so that she can be enjoyed and studied for a very long time to come.