Historically, cannons were made from wrought iron, cast iron, or bronze.
Small light basic cannons, or Culverins, had been used on ships during the Middle Ages. Usually they were fired by individuals or by two or three men from deck firing positions. Ships can only have a small number of light guns because large guns are very heavy and a heavy object placed on the deck of a ship will always make it unstable. It wasn’t until Gunports were invented around 1501 that ships could rely on full-size cannons as their primary weaponry. A gun port is a window, cut into the side of a ship’s hull, from which a cannon can be fired. They allowed the cannon to be installed in the lower part of the ship. The gun gates had hinged wooden doors on top of them so that the gun gate could be closed when the gun was not fired. This stopped the wash of water entering the boat from the waves or when the boat was listing. This meant that a ship could have many powerful and heavy cannons, without becoming unstable, and the cannon soon became the main armament in naval warfare. An early example is the Mary Rose, built in 1512. The Mary Rose had 78 guns, but was later increased to 91.
From the mid-1600s onwards, war at sea was dominated by the tactical system known as the ‘battle line’, this involved a fleet of navy ships forming a long line, parallel to their opponents. The ships would then fire ‘volleys’ with their cannons at their opponents in an effort to sink or paralyze them. With this in mind, the British navy divided their ships into six classifications, based on the number of weapons (military term for a cannon) they could carry, only the three main classifications were known as ‘ships of the line’. A first class ship had to carry more than 90 guns and could have up to 140 guns, distributed over 3 or 4 gun decks, a second class ship had more than 80 guns and a third more than 54. To the fourth category ( not a true ship of the line) had more than 38, a fifth more than 18 and a sixth more than 6 guns.
Naval weapons generally refer to the weight of the shot they fire, so a ’42 pound ‘was a cannon that fired a cannonball or a’ shot ‘that weighed 42 pounds. The 42 pound cannon, also known as a “standard” size cannon, was used on ships from around 1600 to the early 1700s. They were huge. The barrel was about ten feet long and weighed about 3.4 tons on its own. A 42-pounder would have required an 8-man team to fire. They were very powerful and had a good range, the downside was that they were cumbersome, slow to fire, and required a large gun crew. The 42 pounds would always remain on the lower cannon decks, otherwise its weight could unstable the ship.
A cannon most used in the British navy during the 1600s, 1700s and early 1800s was the ‘Demi Cannon’, or 32 pound. This was smaller and lighter than the 42 pound, requiring a 6-man gun crew and with a 9’6 “gun that weighed around 2.6 tons. The Demi Cannon was in use from the early 1600s to the early 1800s. It had a maximum range of 1.5 miles and was reputed to be able to pierce a meter of oak at close range. 12 and 24 pound guns were also very popular, being lighter and faster to reload, they could be mounted on decks. superiors of a cannon, ship without making it unstable, these constituted the bulk of HMS Victory’s armament.
The ‘Carronade’ was a barrel design that was used in a variety of sizes, from 6 to 68 pounds of shot. It was developed in the 1770s and was used until the 1850s. The Carronade was developed by a Scottish company and machined to a high standard to allow a perfect fit between the ball or shot and the muzzle. This meant that the cannonball only fit into the barrel (the hole was only slightly larger than the diameter of the shot, there was less “wind” in naval terms). The chamber for a Carronade’s powder charge was one caliber smaller than the hole where the cannonball sits and is fired, this meant it had a smaller powder charge firing a larger shot. This meant that the internal stresses in the weapon were greatly reduced, so you could have a small, light barrel that would fire a great heavy shot. The downside was short range and limited accuracy. A Carronade could be fired by a 5-man gun crew, and its light weight meant it could be used on the deck of a ship. A Carronade weighs approximately one-third the weight of the equivalent standard gun. A 68 pound cannon had a maximum range of about 7 miles. The Carronade was effective at close range and was referred to as “the crusher” because of the splinters it caused on impact.
Most of a ship’s cannons would fire sideways (port and starboard), however it was common practice to have some cannons aimed from the bow or stern. A so-called “long nine” pistol was used for this purpose, firing only a nine-pound shot, the longer barrel provided additional power and accuracy, and fit well into the available space.
The Paixhans weapon was introduced in the 1840s and revolutionized naval combat because it was a direct firearm that could fire an explosive-filled projectile in a time-delay fuse. This marked the end of the conventional cannon. The introduction of fluted drills and steel jacketed barrels heralded a new era of naval combat and led to the demise of the wooden-hulled warship.