The Pirate's Grave is the first and easiest discovery one can make as soon as they begin the game. Lower the Albatross's altitude and look to the right, and the discovery is on a floating rock. It is almost impossible to miss, as the natrual action is for the player to move directly forward, which will cause the Albatross to pass almost directly over the discovery's location.
It appears that someone has scribbled onto the stone: "Here lies an unknown blue rogue." The actual name has been worn away by the wind, but the first letter, "D," can still be made out. Nobody remembers who rests here.
This may be Daccat's grave. Although the evidence is far from conclusive, it is plausible. First letter of the name, "D," and a blue rogue, apparently dead for a very long time. Daccat seems to fits all three of those criteria, so it may indeed be Daccat who is buried here. It is also notable that there are a number of other discoveries related to Daccat, so this may also be part of that trend.