Keep anything that has an open inventory off the deck (campfire, smithy, etc). Then the only way they can overburden your ship is to load up a player. So park it off shore a bit to at least make it a colossal pain in the butt for them, maybe they will just pass. They are also increasing the load capacity on ships by 40% so it should become MUCH harder for griefers to do it Maybe some of this will help.