You're the Captain, sailor of the seven seas. You right wrongs, fight injustice, save innocent children and... Wait, no you don't; that's some other guy. You just like the ocean.
This is your trusty boat, the Little Skipper. She's a fine craft and will take you where you want to go. Take good care of her and she'll take good care of you.
So what do you, the venerable Captain, do? Explore the seas? Chart new islands? Search for sunken treasure? Fight pirates? Whatever you feel like, you're the Captain. You don't take no guff from nobody.
Seafarer is a procedural nautical adventure game where you the player decide how you want to play. You can explore vast distances, go fishing, search for sunken treasure, fight pirates and so on. You will come across new sea vessels and weaponry in your adventures that you can take for your own. Some people may welcome you and some may curse your name. What will your legacy be, Captain?