I think they did win on their merits. hey figured out your tactic or strategy and beat you. Its not their fault that you are so predictable.
I think that battleboats is one of those games where you should only play private games if you want to be really good at it. Then the only person who could learn anything from your play would be the person you are playing, and rightly so. But they would have to beat you to actually know your placement for that game. And would have to play you often to figure any patterns. And you could always mix things up once in a while. if you think they are playing against your tendancies.