On Diamond Steppe Island. You'll need the Hookshot to get on the island.
The mini dungeon is very annoying due to lots of floormasters, but when you get to the end, you'll get the ghost ship...
Unlike other charts in Zelda the Wind Waker you are unable to actually read this chart. Once you get this chart you must find an Island where the ghost ship appears on some nights. I used Bomb Island...