Tips, tricks & notes:

The pirate island has a pub, some shops (including a fish shop, a pirate clothes shop, and a pirate sword shop) and some pirates to talk to. To talk to any of the pirates, you need The Little Book o' Piracy to be in your inventory, this includes being able to talk to or buy from the pirates with shops.
If you talk to Bill after the quest, you will get 10,000gp from him.
When you leave the ship, including when you complete the quest, all items gotten from the ship or chests will be taken from you, so don't bother getting extras.
If you forget to clean out a cannon before the next shot, you will fail and take 5 damage.