Blackadder Mr K: That's just a battleboat variant with more boats. Except that you might be lucky and you win before you've sunk all.

A hard battleboats variant I used to play was that, just as in dark battelboats, you always get three shots. But if your salvo has any hits, all you are told are how many hits you have - not which shots were hits. But I wouldn't play such a variant here, just as I don't like playing dark chess or espionage on turn based sites.