The Naval Cannon was similar to a regular cannon, but projected fire balls at an arched angle in order to cause wide-ranged damage. To fire the cannon, one had to pull a lever near the cannon. It was meant to be powered by two people, one to steer the gondola, the other to actually fire the cannon.
Placement
The cannon was placed on a small boat (which appeared to be a widened gondola with stabilizers) so that it could be piloted around a harbor in Napoli, and was used by the Assassin Ezio Auditore to destroy four Templar battleships. After he destroyed the battleships, Ezio aimed the cannon towards the boat itself and dived into the water before it was destroyed.
Trivia
Successfully using and destroying the machine gains the player the "Splash!" achievement.
File:Acb-naval-canon.jpgConcept Art of the Naval CannonMiniature replicas of all the war machines can be found at the Armory in Ezio's Hideout after completing their respective memories.
It was only used once throughout the single player story in the side mission Loose Cannon, which can be replayed at any time once completed.