Not trying to encourage violence or anything but seeing as I doubt you can carry a weapon on a cruise ship.....A can of hairspray and a lighter makes a handy blowtorch....LOL
Boil up some of the leftover cooking oil and dump it on them.
Molotov cocktails would certainly liven up things on the average pirate ship. Pretty easy to make.
We used to play war with those little green plastic army men and we painted a lot of them with red fingernail polish for wounds and we used the hairspray as blow torches and melted them.