I only like to do main quests! It's boring to sit around all day just defeating ships for no reason getting no reward but a nautical level please add more into the main quests!!
But nautical level Is a reward, not to mention all the gold and gear drops you get from those ships. Some of those ships drop gear that is identical to the crown shop gear in all but name and perhaps look. The rewards are really there. Perhaps you could join in the fighting with other pirates you see fighting. They will really appreciate the help and you may find some great friends in the process. Checking the fan sites for nautical xp parties and joining those will also ease your boredom and you will have a lot of fun clearing the skyways repeatedly as the fleet shows it's power.