Cannon ports - holes to poke through cannon muzzles or barrels - can be seen along the side of the ship.
The cannon had to be rolled back and the powder, shot and wadding rammed down the muzzle.They were then pushed back in place before a light was put to the touch hole.
The cannon had to be roped to the side of the ship or the kick on explosion would have sent it ricocheting across the deck.
The barrel would become very hot and, if over used, would explode, damaging its own ship and killing the firing squad!