My son found this while wandering around - trying to figure out what it goes to - a mission or what? It has a door that is operable but it doesn't open.
Mission chain (hermit is somewhere between 12 and 13, he will show you the shipwreck)
Although if you'll follow the guide and go straight to the coordinates instead of following the ingame clues, you won't meet him and a lot of other npcs, the chain will be completed but you'll miss part of the fun.