This page has details on the treasure chest buried at coordinates (633,784)
Contents
Treasure Map Location
The treasure map for this treasure was found in Great Inagua to the west of the port, in some cave (use the trees to reach the a platform above and then slide down a hole into the cave):
Treasure Map Screenshot
Screenshot of the treasure map:
Treasure Chest Location
The treasure chest is found in Nassau - Coordinates (633,784)
Where to dig
See map and screenshot below from dig location. It is near a swamp, close to a wall of rocks (on the bottom side) also there is a tree growing diagonally out of the swamp nearby:
Chest Contents
Loot from this chest is 3000 Spanish Reales and plans for Gray Sails