i have some more ideas for consideration:
if two ships gets too close, you have a chance to get entangled riggings, for example if one is turning and your mast hit the other ships mast, and then a chance to topbrake the mast, also the ability to ram your opponent, doing damage depending on armor, structure and speed.
another idea is the ability to level your guns to shoot either hull or masts, and having a timer for when the cannons are leveled enough to shoot the masts, unless it is too close and the guns cannot be leveled enough =)