Ubisoft has already showcased some of the ways Assassin's Creed 4 iterates on the naval combat from AC3. A new video walks us through another kind of naval engagement that has seen some new revisions: attacking a fort with your ship.

Game director Ashraf Ismail explains some changes made to the weapons systems, and random factors like weather or the number of enemy forces. Ismail also says that once a fort has been taken, it will continue to attack enemy ships for you.