I personally don't think we should have galleons and battleships at all, from what I recall they were more Rennaisance-era ships than Medieval. Early cannons were really big and heavy, and now that people mention it I do think ships were probably stronger than some people think. They didn't just splinter into pieces after a shot or two. But naval warfare isn't really mt strong suite, so what I can add to this conversation is limited.

EDIT: Also, HazmatMedic, you are the GM and you really shouldn't be saying 'screw you' just because someone's trying to give you some constructive criticism.