It has potential.
The gameplay is bland. While you have tried to copy Pirates!, you took only the bare-bone features. There's very little to do outside of battle. There's no trade, no fun mini-quests or wives, just sailing around, hoping to find an opponent.
The ship fights themselves are frustrating. Sometimes, they sail away and you have to spend half an hour finding the opponent. The AI has no tactics, it simply goes in circles, spamming round-shot. No fun there.
The camera is horrible. Sometimes, you're sailing into the edge of the screen, unable to see anything in front of you.
It also seems like ships, shot, men, etc don't matter at all in combat, only the range of the cannon.
The isometric pixel art is an interesting choice, though, and the overall look is very good.
I'm sorry, this game has a lot of potential, but it's just not cutting it.