Dungeons and Dragons

In terms if crew positions, mine might not be the most realistic but are designed to give the players interesting roles and ways to effect things.

The Captain - gives orders, makes in-the-moment tactical decisions

The Quartermaster - in charge of the crew and keeping them fed and watered, in charge of rum rationing as well

Lookout - doesn't seem like much, but if you put a PC with high perception in that role, you'll spot stiff better

Cook - has a big effect on the morale of the crew

Shantyman - perfect role for a bard. Also has a big effect on morale and can inspire great feats from the crew with performance checks.

Bosun - in charge of maintaining the ship, when repairs are needed, etc.

There is a pirate code that they are expected to follow. Captain Verse insisted on this when he helped the players take their ship. Its quite long but the big points are:

• All booty must be shared equally, with tge Captain and the officers getting two shares each.
• All major decisions must be decided by vote (such as whether to take a prize, where to burn a ship or take it...). The crew may even vote out their captain if they dislike how the ship is run (although in practice I'd likely just do a good old mutiny).
• No one may steal from another member of the crew, on pain of being marooned, keelhauled, or killed.
• No murdering each other, although fights are tolerated within reason. If they get really bad they must be settled ashore.
• you can't leave the rew until you've at least helped the make a prize.
• No freeloading, everyone pulls their weight

Generally the pirates work together, and if there was a local pirate leader that would be Captain Verse. Some go rogue or shun the pirate code, like the BBEG pirate captain Blackfin, who's crew are mostly undead and who has no allegiance other than to his Demon Lord, Orcus. Verse has done a great job of uniting at least rhe pirates in the Western regions of the Isles, and hopes to lead an uprising against The Company and start a pirate republic.