If it is in a nation's territorial water there's going to be some caveats to that depending on the nature of the debris, circumstances under which it was abando

If it is in a nation's territorial water there's going to be some caveats to that depending on the nature of the debris, circumstances under which it was abandoned and other specific facts of the situation. There are all sorts of laws regarding property that is abandoned in various contexts that could apply in those cases and in many cases these laws can conflict with the maritime laws of that nation and international maritime laws (the former may very well just be a pointer to the latter in many cases). Handling these gray areas is why we have courts. Imagine some subcontractor to an oil company is forced to abandon a small craft in protected federal land in Alaska. You've got federal maritime law, state law, federal law regarding resource extraction, federal law regarding protected land, etc, etc. Some of these laws are intended to give the property owners the right to go get their stuff back on a very, very permissive timetable. Some of these laws are intended to let the locals, state, feds, even general public, claim the property almost as soon as their want in order to facilitate speedy remediation. Oh and remember, possession is 9/10ths the law so that could get weird depending on if the abandoned property is titled property, etc. This crap can get real complex, real fast. A lot of these potential conflicts have been hammered out via case law but many of them also haven't and different facts can make the prior case law not very relevant. If neither side is willing to settle it could really drag on.