If pirates be boarding you more than they oughtta, you can make it more tricky by chumming the water.
Sharks are scary / fun, and being able to lure them in, and have multiples of them, would be an entertaining way of making falling in the water more hazardous. It'd also be a great way of trying to safeguard your boat when folks are trying to swim aboard.
It could also backfire badly, which is hilarious.
