Several men were needed to fire a cannon on a 16th century ship. First, a loader packed gunpowder into the barrel, followed by the ball. A “sponger” used a long stick called a rammer to push both powder and ball down the barrel. The gun crew hauled on ropes to pull the cannon to the gunport. The gunner held a burning taper to a hole at the end of the gun, lighting the gunpowder.

Readying the cannon

Each gun crew consisted of a gunner (artillero on a Spanish galleon) supervising three or four sailors and a ship’s boy, whose job was to fetch gunpowder and shot from the store. The first job was to remove the tompion, the stopper that closed off the muzzle, and to unseal the vent or touch hole. Next, the loader took a cartridge (a case of gunpowder) and placed it in the muzzle (1).

The rammer shoved the cartridge down as far as it will go (2). He used a pole which had a sponge—for cleaning out the gun after a previous firing—at its opposite end. Then the shot was inserted, followed by a wad, usually made of oakum, fibres unravelled from old rope. The cannon was now ready for firing.

Lighting the powder

Now the gunner pricked the cartridge through the vent with a priming wire (3) and filled the vent with gunpowder from his powder horn, pouring a little just behind the vent (4).

Pulling on the breech ropes through the ringbolts, the gun crew hauled the heavy cannon so its muzzle stuck out of the gunport (5). The precise direction of the gun could be adjusted slightly using handspikes (levers). When the order came to fire, the gunner took his linstock, struck the match and touched it to the powder just behind the vent (6). With the ship rolling up and down in the waves, his timing was crucial.

Immediately after the gun was fired (7), it recoiled—jumped backwards—into the ship. While the muzzle was being sponged for the next firing, the gunner placed his thumb over the vent to prevent any air accidentally igniting the gun.

Swivel gun

A verso or swivel gun was a breech-loading firearm: it was loaded at the rear of the barrel, not through its muzzle like a cannon. It could therefore be readied for firing much more quickly. Mounted on a yoke fitted to the rails around the upper decks, it could be easily swivelled towards its target. The gunner loaded a mug-shaped device called a chamber, which was filled with gunpowder and shot—a musket ball or a mixture of nails.