Bowdash calls his home a mansion, but inside there is a table, a fireplace, some barrels, a searchable dresser, a chest, some wood, and many bags of some sort of item. Not much of a mansion for the man who calls himself "The King of Tortuga".
It's a fairly modest home with a few pans, chairs, benches, and lights.
The mansion has no purpose in quests, and currently has no NPCs inside it. Though, at one time, a couple of Bowdash's quests included searching the mansion for objects to return to him.
Many pirates like to claim the mansion as their home, and it is frequently used for private parties in-game.