How to: Build a replica Cannon Part One

The Background

History Part One of this series begins with a very brief look at the history of a typical naval gun in use with the Royal Navy of the 18th- and 19th-centuries. The story of such cannons, however, begins in 12th-century China where gunpowder, the first explosive, was developed[1]. Gunpowder was employed in warfare to some effect from at least the 10th-century in weapons such as fire arrows, bombs, and the fire lance before the appearance of the gun. The earliest European references to gunpowder are found in Opus Majus written by English philosopher and Franciscan friar, Roger Bacon, in AD 1267. The earliest known European depiction of a cannon, however, appeared in a manuscript[2] by Walter de Milemete dated to AD 1326. The cannon depicted is loaded with a large arrow emerging from it and its user lowering a long stick to ignite the cannon through a touchhole.

Continued development led to the construction of larger, more powerful cannon. By end of the 15th-century, several technological advancements were made, making cannon more mobile. Wheeled gun carriages and trunnions (pivot points) became common, and the invention of the limber further facilitated the transportation of artillery.

By the middle of the 16th-century better powder had been developed, and cannon were being made in a great variety of lengths and bore diameters. The general rule was that the longer the barrel, the longer the range, but with some many variants, European monarchs began to classify cannon to simplify logistics. France opted for six sizes of cannon, the Spanish used twelve sizes, and the English sixteen.

Design The design for our replica follows the plans for an English type 24-pounder long gun, which was a heavy calibre piece of artillery mounted on warships of the Age of sail.  The 24-pounder saw service in the navies of France, Spain, Great Britain, the Netherlands, Sweden, and the United States.  They were used as main guns on the heaviest frigates of the early 19th-century and on fourth-rate ships of the line, on the second deck of first-rate ships of the line, and on the second deck of a few large third-rates.

A notebook dating to 1720 mention that the British used four lengths of iron 24-pounders: 10, 9½, 9, and 8½ feet long.  Ten surviving guns, which are likely examples of the 9½ foot (2.9 m) version, weigh between 48 and 49¾ hundredweight (approx. 2349 to 2527 kg).

Gun Drills Firing a naval cannon required a great amount of labour and manpower. During the Napoleonic Wars, a British gun team consisted of 5 numbered gunners - fewer crew than needed in the previous century. The No.1 was the gun commander who aimed the gun and directed the typical firing procedure as follows. The No.2 was the "spongeman" who cleaned the bore with the sponge dampened with water between shots, extinguishing any embers from a previous firing which might set off the next charge of gunpowder prematurely.

The bulk of the gunpowder was kept in the ship's magazine, a special storage area below deck for safety. Powder boys, typically 10-14 years old, were enlisted to run powder from the magazine up to the gun decks as required. Scrambling through the confined spaces of a warship to keep the guns supplied with powder may explain the sobriquet "powder monkeys" by which these boys were also known.

The No.3, the loader, inserted the powder, either loose or in a cloth or parchment cartridge, into the barrel followed by a cloth wad (typically made from canvas and old rope). The No.2 then used a rammer, or the sponge reversed, to drive it firmly into the breach. The No.3 inserted the projectile, followed by another wad to prevent the cannonball from rolling out of the barrel if the muzzle was depressed, and rammed home by the No.2. At the same time, the No.4 ("ventsman") pressed his thumb on the vent hole to prevent a draught that might fan a flame[3]. The charge loaded, the No.4 pricked the bagged charge through the vent or touch-hole and then primed the vent with finer gunpowder (priming powder) or inserted a quill (from a porcupine or the skin-end of a feather) pre-filled with priming powder.

The gun in its carriage was then "run out"; men heaved on the gun tackles until the front of the gun
carriage was hard up against the ship's bulwark, the barrel protruding out of the gun port. This took the majority of the gun crew as the weight of a large cannon in its carriage could total over two tons, and the ship would probably be rolling.

At the No.1's command the No.5 would fire the piece with his slow match[4]. The earlier method of firing a cannon was to apply a linstock - a wooden staff holding a length of smouldering match at the end - to the touch-hole of the gun. This was dangerous and made accurate shooting difficult from a moving ship, as the gun had to be fired from the side to avoid its recoil, and there was a noticeable delay between the application of the linstock and the gun firing. In 1745, the British began using gunlocks (flintlock mechanisms) fitted to cannon, which were operated by pulling a cord or lanyard. The gun-captain, the No.1, could now stand behind the gun, safely beyond its range of recoil, and sight along the barrel, firing when the roll of the ship lined the gun up with the enemy, and so reduce the chance of the shot hitting the sea or flying high over the enemy's deck.

The linstock slow match or the spark from the flintlock ignited the priming powder, which in turn set off the main charge, which propelled the shot out of the barrel. When the gun discharged, the recoil sent it backwards until stopped by a breech rope. This sturdy rope was fastened to ring bolts let into the bulwarks, with a turn taken about the gun's cascabel (the knob at the end of the gun barrel).

Gunners' Equipment The core element is the barrel so named because the earliest guns were constructed with iron staves bound securely by hoops as was the case in coopering a cask or barrel. The other key piece is the gun carriage, but cannon are useless without projectiles to fire and the equipment the crew needs to serve the gun. According to its section on gunnery, 1771 edition of the Encyclopædia Britannica notes the equipment needed as follows:

The sponge is a long staff or rammer with a piece of fleece sheep or lambskin wound about its end, to scour the cannon when discharged, before it is to be charged with fresh powder. This cleaning prevents any spark or fire from remaining in the piece, which would endanger the life of the loading crew. Sponges were the most commonly used cannon cleaning instruments.

A wad-screw or worm is formed of two points of iron in the shape of a corkscrew and used to extract the wad out of the gun. It is also used when the cannon has to be unloaded or dirt removed.

The lantern or ladle serves to carry the powder into the barrel where a bagged powder charge is not used.

A rammer is a round piece of wood, commonly called a box, which serves to drive home the powder and ball to the breech. It is fastened to a stick twelve feet long, for the pieces from twelve to thirty-three pounders, and ten feet long for the eight and four pounders.

A priming iron is a pointed iron rod, used to clear the touch (vent) hole of burnt powder or dirt. It is also used to pierce the cartridge so the priming powder when lit ignites the main charge.

The primer must contain a pound of gunpowder at least, and is used to prime the vent hole.

The botefeux is used to hold a winding of match with which to fire the cannon. This may be a stick two or three feet long with a split to hold one end of the match.

Next... In Part Two, we will begin the build by constructing that essential component of the cannon, its barrel.

Notes:

1. Gunpowder was discovered during the late Tang dynasty (9th-century AD) but the earliest record of a written formula appeared in the Song dynasty (11th-century). Knowledge of gunpowder spread rapidly throughout Asia, the Middle East and Europe, possibly as a result of the Mongol conquests during the 13th-century, with written formula for it appearing in the 1267 Opus Majus treatise by Roger Bacon and a 1280 treatise by Hasan al-Rammah.

2. De Nobilitatibus, sapientii et prudentiis regum (Concerning the Majesty, Wisdom, and Prudence of Kings).

3. A leather patch was often used to cover the touch-hole, when the piece is charged, to keep dirt from entering the touch-hole.

4. Friction primers replaced slow match ignition by the mid-19th century.