The Burning Wheel could be an excellent system choice for running an RPG about piracy, especially if you want to focus on the rough and gritty life (and quick death) that is the lot of the privateer. BW is a crunchy fantasy RPG with a lot of good, character driven elements to help you flesh out just what your pirates are willing to kill or die for. (Plus, the “Duel of Wits” social combat system would be great for trying to stave off a mutiny!) Check out these threads:
- Burning Pirates—Prep for play
- Burning Pirates—Prep for play
- BW Pirates – Design Help?
- Blackbeard had a grey MW (This is one of those “stat a historical person into a system” threads, so be forewarned.)