How many generations must pass before such a site passes into being able to be scavenged for items of interest? There have never been remains found. In some wat

How many generations must pass before such a site passes into being able to be scavenged for items of interest? There have never been remains found. In some waters you could find bodies but not where the Titanic sits. Has it aged enough to fall into the same category we assign Egyptian artifacts? We have dug up remains of many societies and some are within a few hundred years of age. So it really comes down to, what is the rule? To me it should be allowed to retrieve items from the site and if no national government wants to sponsor it then why not a private organization? if placed under proper restrictions but not outright confiscation they should be able to operate as a museum type organization taking their historical artifacts on tour so others may enjoy them