Star Belt Archipelago
From The Wind Waker Randomizer
Star Belt Archipelago is a collection of rock spires at G-3 and has a platform and sunken treasure.
Platform
If all of the Bokoblins are defeated on the nearby platform, a chest will spawn, which has a Red Rupee (20) in the vanilla game.
Sunken Treasure
The treasure can be located by opening Treasure Chart 27 if charts are not randomized and contains a Silver Rupee (200) in the vanilla game.