The Legend of Zelda: The Wind Waker/Quest charts

Quest charts are special charts that display information on the locations of things such as submarines, platforms, and the Ghost Ship.

The Platform Chart
The Platform Chart shows which sectors the tall platforms with gun turrets and the skull-head roofs are located in, and how many.
 * Found in: Submarine in Flight Control Platrorm Sector (G2).

Secret Cave Chart
This chart shows the location of the various Secret Caves.
 * Found using: Treasure Chart 13 from Two-Eye Reef.