any ship cannot leave a country from which it doesn't originate and return without stopping at another country
What? Might one put that in simple English please? Everyone has to be from somewhere.
I have heard of the Jones law: Prohibits ships of Non-U.S registry from embarking and debarking guests at two different U.S ports. Such travel would constitute point-to-point transportation between two U.S ports, which is prohibited on foreign flagged ships. US registries are of course exempt. Most sizable ships are registered with other nations due to our horridly expensive fees.