There are 'ghost ships' on pirate isle when you take a boat to one on these it costs you two pearls and then it will say step up to enter the ghost boat so step up and then there is a quest for you to do: deck swabs they are called!
there are magic pots, some are covered with logs, burn them and go inside. it will be tough because some take you where you started so try each one until you see the chest.
You just sail towards it. It'll automatically teleport you in when you get close enough. When you beat it, you'll be automatically teleported out and it'll be day.