I agree with you (somewhat). In other cases, Spain has won the rights over salvaged treasure from sunken Spanish ships, as the countries they plundered the gol

I agree with you (somewhat). In other cases, Spain has won the rights over salvaged treasure from sunken Spanish ships, as the countries they plundered the gold from weren't countries at the time, but colonies of Spain (for example: Peru). Sincerely, if this is in International waters, you would think there was a expiry date of shipwrecks and it's finders-keepers after, Oh, I dunno, a few hundred years or so.