If you want to know where the ghost ship chart is, it's on the island one square above and one square to the left of Outset Island (Northwest). You use the hookshot to get onto the island, and use it some more to get to the top. There's a hole. Fall in the hole. From here on it'll be sort of trial and error, but jump into the smoky, teleport pots. Certain ones will lead you to different areas with more teleport pots. Eventually, you'll get to the chart, which is on a chest on some wrecked boat down there.
Funny thing is, I just showed that to someone yesterday, in person. . . weird. . .