Honestly if I was going on an ocean going vessel I would be more concerned with the safety of my weapon from the elements. On the open ocean you are less likely to need a weapon for defense. Except in the case of pirates of course. I don't know if this is true but I have heard that there are laws restricting how many guns you can take on an ocean going boat. I wouldn't go without a good rifle in a plastic bag that can be easily accessed. I only ran into pirates once, in the Persian gulf, And they were scared off by our big Navy guns. They came up on us at night, we run dark, they must have thought we were a powerless transport vessel of some kind. They were surprised.