Ships at War .
This sounds a lot like Battleships...
I would avoid that name for sure though, as it is copyrighted. You can still have the same rules and premise of battleships, so long as they are written in a different way, and the game is called something different.
It's the same as a recipe: there must be hundreds of recipes for pumpkin pie, but you are still allowed to publish your own one even if you didn't invent the pumpkin pie, so long as the recipe is written differently from how someone else has already written it.