There are lots of problems with keeping weapons aboard ships. First, your insurance rates will go UP. 2nd, many countries will not let you enter their ports with weapons, those that do require lots of paperwork with serial numbers, amount of shells and bullets on board before and after leaving port, etc. Not to mention the visual inspections. Basically, they don't want you to have them either. In my time as crewman on a commercial work boat, the US Coast Guard wouldn't let us carry them either with passengers on board. Makes no sense but that's the government for ya.