I joined this conversation late, but I'm running a Pirate campaign using
Pathfinder's Skull & Shackles pirate adventures as a framework, and my players just got their own ship after a mutiny:
- Skull & Shackles rocks for adventure ideas.
- Getting your own ship should be cool. You should want to advance your ship, which becomes a mini-game. I'm applying Fire As She Bears (3rd edition) rules on ship combat, which are an advanced mini-game wherein everyone contributes during a ship to ship combat and you can spend gold to upgrade your ship, but you could also use Matt Colville's Strongholds and Followers idea of a ship as a "base" (kind of like a wizard's tower, or a fighter's keep). Alternately, you can ditch this mini-game idea altogether and just have "cool" encounters between ships (either boarding actions, cursed ships, roleplay of merchant ships giving up their cargo to pirates, etc.).
- The Paizo forum for Skull & Shackles is invaluable for ideas. One commenter collected all Dungeon Magazine pirate-ty adventures.
- Here are most of my notes for rules on ship loyalty, infamy, vices (replacing inspiration), NPCs, the S&S rules on plunder, some DM notes for pirate language, better gunpowder rules, and our campaign guide. Might be worth a few ideas.
Finally, as far as philosophy, pirates don't have to be totally evil. Piracy is one of the earliest forms of true democracy, founded in the idea that while you don't have a voice or say or may get screwed over with pay working for "the man" (insert nation with navy), true pirates have a voice on their ship, get equal shares, and share equal risk. It might be more Robin Hood-ish. That all said, every gamer needs to buy in before you start a pirate campaign that we're not playing "goody two shoes." Being a pirate means you don't forget a slight, you keep what you can take, and ultimate freedom is the ultimate code to live by.