The Mary Rose ship sank in 1545. When in 1982 it was raised from the sea, 1,200 cannonballs were discovered. It is a huge historical treasure, worthy of preservation, but chlorine from seawater damages iron very easily when it is exposed to air. Now scientists from UCL, The Mary Rose and Diamond Light Source made major advances in attempts to preserve the cannonballs from the Henry VIII’s flagship vessel.
Chlorine can be removed – this was done with hope that it will stop cannonballs from disintegrating. However, the process of corrosion did not stop after cannonballs have been displayed for public to see. And people must be able to see these artefacts of historical weaponry and sea battles. That is why scientists have been looking for better preservation methods ever since. However, even with our current scientific methods, it is still trial and error – scientists are trying various methods and checking how they work using an advanced X-Ray imaging technique.
Scientists took 12 cannonballs from the batch for the research. 6 of them were cut in pieces – while this seems like a destruction of historical artefacts, this may help saving the others. On the other hand, scientists are experimenting with only 1% of the balls, so that reminder can remain untouched until times comes to put the newly developed preservation methods to use. All the cannonballs were raised from the sea at the same time and they were made in the same foundry – only one iron blast furnace existed in Britain at the time of the Mary Rose’s construction. This means that a solution discovered testing 6 or 12 cannonballs will apply to all 1,200.
X-Ray machine has been crucial to the process. It allows imaging the corrosion and which elements are participating in it. Also, it helps seeing how various methods are affecting the corrosive process. Hayley Simon, one of the researchers from the team, said: “These results represent a first step towards the development of new protective techniques. We are launching a long duration experiment next, which will observe changes in the corrosion product during long-term immersion in various conservation treatments to monitor their effects”. Samples, taken from the cannonballs are required for accuracy. This is a small sacrifice, which, hopefully, will help preserving these cannonballs for generations to come.
Scientists are also saying that methods they are developing will be useful around the word to deal with iron-rich artefacts. Currently, historical pieces raised from the sea are corroding at a fast pace and scientists can only slow down this process. However, soon there should be reliable new preservation methods.