The long maritime history of Britain offers an opportunity for the study of chemical changes in wood after extended immersion in aqueous environments. There are an estimated 46,000 shipwrecks in British waters today ; an unknown proportion of these are wooden. Rapidly changing coastlines mean that new shipwreck sites can appear and disappear quickly. The ability to rapidly assess the state of a wooden shipwreck will assist in determining what conservation efforts are appropriate. Furthermore, there are a number of preserved wooden vessels in both public and private hands: these massive historic artifacts require continuous care and monitoring . The importance of understanding the degradation of wet and waterlogged wood is not just limited to naval architecture; studies have also been carried out on submerged archaeological samples and sites , wooden samples from salt mines and active foundations below the water table in Venice, Italy .