Super Basic Idea: You meet an NPC on an outpost or island that wants to go to another outpost or island. Some pay well, some pay poorly. Some get drunk and throw up all over your boat. Some just stand quietly on deck and contemplate the sea. Others tell you tales of hidden treasure. They can be killed, though some might fight back! But you don't get your pay if they don't make it to their destination.
This just adds another interesting layer to a session of play.
Thoughts?