Been working hard on your pirate island aren't you? Well, that's how things go along - you don't expect your pirate to build up itself alone. Make sure you keep up with your quests too, this will help you a lot in making your island more stronger, and plus it's a good source of booties - XP points, grogs, gold and sometime gems, exploring the waters would make some good credit too - just make sure to keep your boat on clear waters in Plunder Pirates.
However, it's a bit hard when you don't know the coordinates of your destination, probably will eat up most of your time circling around the map - I've been in that situation too. To make things a bit easier for you, I think it would be helpful to prepare a list map coordinates of particular exploration and battle destinations. Plunder Pirates Island is here to help and check the coordinates below and take note of these;