Carronade

68-pounder British naval carronade mounted on HMS Victory

The carronade was a short smoothbore, cast iron cannon, developed for the Royal Navy by the Carron Company, an ironworks in Falkirk, Scotland, UK. It was used from the 1770s to the 1850s. Its main function was to serve as a powerful, short-range anti-ship and anti-crew weapon. While considered very successful early on, carronades eventually disappeared as long-range naval artillery led to fewer and fewer close-range engagements.

History

The carronade was designed as a short-range naval weapon with a low muzzle velocity. Its invention is variously ascribed to Lieutenant General Robert Melville in 1759, or to Charles Gascoigne, manager of the Carron Company from 1769 to 1779. In its early years the weapon was sometimes called a "mellvinade" or alternatively, a "gasconade".^[1]

Carronades initially became popular on British merchant ships during the American Revolutionary War. A lightweight gun that needed only a small gun crew and was devastating at short range was a weapon well suited to defending merchant ships against French and American Privateers ^[2].

The Royal Navy was initially reluctant to adopt the guns, mainly due to mistrust of the Carron Company, which had developed a reputation for incompetence and commercial sharp practice^[2]. Carronades were not even counted in numbering the guns of a ship. However, Lord Sandwich eventually started mounting them in place of the light guns on the forecastle and quarterdeck of ships. They soon proved their effectiveness in battle. French gun foundries were unable to produce equivalents for twenty years,^[2] so carronades gave British warships a significant tactical advantage during the latter part of the 18th century.

The carronade was initially very successful and widely adopted, and a few experimental ships (for example, HMS Glatton and HMS Rainbow^[2]) were fitted with a carronade-only armament. Glatton, a Fourth-rate ship with 56 guns, had a more destructive broadside than HMS Victory, a First-rate ship with 100 guns. Although Glatton and Rainbow were both successful in battle, the carronade's lack of range against an opponent who could keep well clear and still use his long guns was a significant tactical disadvantage of this arrangement.

In the 1810s and 1820s greater emphasis was placed on the accuracy of long-range gunfire, and less on the weight of a broadside. Indeed, Captain David Porter of USS Essex complained when his 12 pounder long guns were replaced with 32 pounder carronades. The carronade disappeared from the Royal Navy from the 1850s after the development of steel-jacketed cannon by William George Armstrong and Joseph Whitworth. Carronades were nevertheless used in the American Civil War in the 1860s.

Design

The lower muzzle velocity of a carronade's round shot was intended to create many more of the deadly wooden splinters when hitting the structure of an enemy vessel, leading to its nickname, the smasher^{[citation needed]}. The small powder charge of the carronade, however, was only able to project a heavy cannonball over a relatively limited distance. The short barrel, low muzzle velocity, and short range also increased the risk that a carronade would eject burning wadding onto nearby combustible materials, increasing the risk of fire.

Ordnance

Diagram of a carronade mounting

Model of a carronade with grapeshot ammunition

A carronade was much shorter and a third to a quarter of the weight of an equivalent long gun: a 32 pounder carronade, for example, weighed less than a ton, but a 32 pounder long gun weighed over 3 tons. Carronades were manufactured in the usual naval gun calibres (12, 18, 24, 32 and 42 pounders, but 6 pdr and 68 pdr versions are known), but they were not counted in a ship of the line's rated number of guns. The classification of Royal Navy vessels in this period can therefore mislead, since they would often be carrying more pieces of ordnance than they were described as carrying.

Although the carronade, like other naval guns, was mounted with ropes to restrain the recoil, the details of the gun mounting were usually quite different. The carronade was typically mounted on a sliding, rather than wheeled, gun carriage, and elevation was achieved with a turnscrew, like field guns, rather than the quoins (wooden wedges) usual for naval guns. In addition, a carronade was usually mounted on a lug underneath the barrel, rather than the usual trunnions to either side. As a result, the carronade had an unusually high centre of gravity. Towards the end of the period of use, some carronades were fitted with trunnions to lower their centre of gravity, to create a variant known as the gunnade.

Range

As a result of irregularities in the size of cannon balls and the difficulty of boring out gun barrels, there was usually a considerable gap (known as the windage) between the ball and the inside of the gun barrel. The windage of a cannon was often as much as a quarter of an inch and caused a considerable loss of projectile power. The manufacturing practices introduced by the Carron Company reduced the windage considerably. Despite the reduced windage, carronades had a much shorter range, typically a third to a half, than the equivalent long gun because they used a much smaller propellant charge (the chamber for the powder was smaller than the bore for the ball). Typical naval tactics in the late 18th century, however, emphasised short-range broadsides, so the range was not thought to be a problem: indeed, their much lighter weight allowed a ship to carry more carronades, or carronades of a larger calibre, than long guns, and carronades could be mounted on the upper decks, where heavy long guns could cause the ship to be top-heavy and unstable. Carronades also required a smaller gun crew, and were faster to reload and easier to aim. HMS Victory used the two 68-pounder carronades which she carried on her forecastle to great effect at the Battle of Trafalgar, clearing the gun deck of the Bucentaure by firing a round shot and a keg of 500 musket balls through the Bucentaure's stern windows.

Diagram

1. Breech bolt
2. Aft sight
3. Vent hole
4. Front sight
5. First reinforcing ring
6. Barrel
7. Muzzle
8. Second reinforcing ring
9. Horizontal rotation axis
10. Chock
11. Vertical rotation axis
12. Wheel
13. Mobile pedestal
14. Carriage
15. Pommel
16. Elevation thread

References

• Originally from http://www.cronab.demon.co.uk/gen1.htm, with the author's permission.
• This article incorporates text from the Encyclopædia Britannica, Eleventh Edition, a publication now in the public domain.
• Kincaid, Jeff (22007) Artillery: an illustrated history of its impact. (Santa Barbara Calif.: ABC-Clio). ISBN 978-1851095568.
• Lavery, Brian (1989). Nelson's Navy: The Ships, Men and Organisation 1793-1815. London: Conway Maritime Press. ISBN 1-59114-611-9.