The main existing structure is technically a tower house, although I would call it a keep. It was built to a very high standard with much higher quality stonework than is typical. The walls are quite thick, with two vaulted floors and a particularly wide spiral stair. It sat on an island with a series of walls, moats, towers and ditches around it providing additional lines of defense and had it's own dock capable of handling a ship of about 100 tons.