You forgot the boat docked in the Imperial Waterworks. I understand technically it isn't yours but once you kill the crew and the campaign it is yours, in fact you can take over as the new owner at the start of the game. Right after getting out of the prison. All you have to do is jump on the boat run and let the guards do the killing. Loot for some gear. Now you own a boat. Although it can glitch until you kill the captain for the dark brother. So if you leave stuff before this there is a small chance you will loose the items. After the quest it is all yours.
