coan.net: Nice ideas, I like the Moving Battleboats best!
Here's another: We already have Behemoth Chess, so why not Leviathan Battleboats? It would be like "plain" Battleboats (one shot per turn), except the "beast" strikes at a random square on each turn, so effectively you have two shots. The random factor means you would have to adjust your shooting pattern during the game.
(hide) If you are waiting for your turn, click on "change" next to the "refresh" on the main page, then set refresh the page to 30 seconds to get your turn to move displayed faster. (Servant) (show all tips)