The international laws of the sea will provide jurisdiction, which means that the vessel remains the property of that nation. If it is within territorial waters, then you apply an additional punitive consequence to do it. An example of that is, if you recall back in the mid-1980s, Dr. Ballard, who was a researcher, found the Bismarck, the German battleship, way out in international waters and indicated that he intended and do some exploration on the Bismarck. That vessel has hundreds and hundreds of sailors still on board who went down with that ship. Germany's response was immediate, very swift, and basically told them that the vessel belonged to Germany under international law and, in order to do anything on that vessel, they would have to request to do that, and it would always be denied because it is not a wreck. It is a war grave.
On February 7th, 2018. See this statement in context.