That depends on how much you like being out at sea. Sailing and Cannons were the first two skills I mastered. Cannon time can fly by if you're with a good crew and are plundering every big ship in sight.

I checked out your Pirate as well. Your nades are way behind your other weapons. That and the fact that, with very rare exceptions, most people don't like lvling nades and that appears to be the case with you, its a no brainier. Use it on grenades. Your in much better shape with cannons and sailing.