You mean battery powered, right?
Offhand, I can't think of any but unless you go battery powered, you'll somehow need to provide some sort of wire feed for the power. You're back to running wires anyway.
But, on the whole, even if you find some cheapo battery powered speakers I doubt they would have the power you need and will also probably sound like shiite. Even then, depending on the construction of the boat, aluminum may prevent the RF signal from getting to the speakers.
You may want to reconsider running speaker cables in some way, shape or form. It'll be the cheapest, easiest and, in the end, provide the ideal solution. A little planning and care in running the wires or even calling in a pro to do it might be worth it.