The Guardian has a good article on the impending excavation of the wreck of the Sussex, a British warship that sank in 1694 while on a secret diplomatic mission for King William III.
The estimated value of the contents of the vessel is £2.4bn. A company called Odyssey will be very rich if it finds what its looking for. The British government will also get its share:
The deal struck between the US firm and the MoD sees Britain get a share of the spoils on a sliding scale, which initially favours the Americans, who would get 80% of the first £28m. Anything more than this would be shared equally, up to £319m after which the Treasury share rises to 60%.
The UK has most of the rights to any artefacts, such as canon, anchors etc. Odyssey’s bargaining position was that it found the wreck, and has borne all the costs – more than £2m so far – and the financial risks, should the project not come off.