BandA wrote:[OT] most passenger ships are foreign registeredFWIW, There's only three ocean prowling passenger ships capable of traveling "overseas" I'm aware of today flying the American flag. USNS Akula (also known as "The Cat") and her sister USNS Guam are fast ferries, and the cruise ship MS Pride of America. You can ride on the Akula during the summer months between Portland Maine and Yarmouth Nova Scotia, American servicemen and families can ride the Guam to and from Okinawa to various Asian ports, and you can ride the Pride of America usually on weekly cruises from Honolulu. In all cases, crimes occuring in International waters are handled by International law.
Getting back on topic, whether a Federal law is made or not, the FBI and other Federal agenices may get involved with the case upon invitation by local law enforcement - which usually occurs anyways. The only valid reason to make it a Federal crime is to change who prosecutes the case in court, the local district attorney or some case lawyer working in the US Justice Department.