The earliest guns were laid directly onto the ground, with earth being piled up under the muzzle end of the barrel to increase the elevation. As the size of guns increased, they began to be attached to heavy wooden frames or beds that were held down by stakes. These began to be replaced by wheeled carriages in the early 16th century.
Smoothbore gun carriages
From the 16th to the mid-19th century, the main form of artillery remained the smoothbore cannon. By this time, the trunnion (a short axle protruding from either side of the gun barrel) had been developed, with the result that the barrel could be held in two recesses in the carriage and secured with an iron band. This simplified elevation, which was achieved by raising or lowering the breech of the gun by means of a wedge called a quoin or later by a steel screw. During this time, the design of gun carriages evolved only slowly, with the trend being towards lighter carriages carrying barrels that were able to throw a heavier projectile. There were two main categories of gun carriages:
These were designed for use aboard a ship or within a fortification and consisted of two large wooden slabs called "cheeks" held apart by bracing pieces called "transoms". The trunnions of the gun barrel sat on the top of the cheeks; the rearward part of each cheek was stepped so that the breech could be lifted by iron levers called "handspikes". Because these guns were not required to travel about, they were only provided with four small wheels called "trucks", whose main function was to roll backwards with the recoil of the gun and then allow it to be moved forward into a firing position after reloading. Traversing the gun was achieved by levering the rear of the carriage sideways with handspikes. An improvement on this arrangement started at the end of the 18th century with the introduction of the traversing carriage, initially in fortifications but later on ships as well. This consisted of a stout wooden (and later iron) beam on which the entire gun carriage was mounted. The beam was fitted to a pivot at the centre, and to one or more trucks or "racers" at the front; the racers ran along a semi-circular iron track set in the floor called a "race". This allowed the gun to be swung in an arc over a parapet. Alternatively, the pivot could be fitted to the front of the beam and the racers at the rear, allowing the gun to fire through an embrasure. The traversing beam sloped upwards towards the rear, allowing the gun and its carriage to recoil up the slope.
These were designed to allow guns to be deployed on the battlefield and were provided with a pair of large wheels similar to those used on carts or wagons. The cheeks of field carriages were much narrower than those on the naval carriage and the rear end, called a "trail", rested on the ground. When the gun needed to be moved any distance, the trail could be lifted onto a second separate axle called a limber, which could then be towed by a team of horses or oxen. Limbers had been invented in France in about 1550. An innovation from the mid-18th century was the invention of the "block trail", which replaced the heavy cheeks and transoms of the "double-bracket" carriage with a single wooden spar reinforced with iron.
Modern gun carriages
In recent times, most heavy guns in military service, that were not themselves mounted into a vehicles, have been mounted either with a field carriage or a split trail carriage.The trail is the hinder end of the stock of a gun-carriage, which rests or slides on the ground when the carriage is unlimbered. The field carriage is simpler, having two legs extend backwards, joining at a tail, being a hardpoint to hook on to a prime mover or set of horses. The split trail carriage, however, is more complicated, but offers distinct advantages. It consists of two legs, able to be spread independently to the sides, or brought together to allow towing or movement.
In both cases, the tail of the carriage often serves to balance the gun, and protect it from rolling to any large extent. The split trail, however, allows the gun not only to be fired near the horizontal, as the field carriage does, but also at angles to main line of the gun. This is less important for heavier artillery, as the guns already involve a long time to prepare a firing position. With smaller support guns, the ability to redirect fire from one area to another, as well as "track" a moving target, is key, and thus many lighter guns, as well as most modern artillery pieces, have split trail carriages.
Some guns, such as the L118 light 105mm howitzer, or its predecessor, the 25-pounder, adapted around the problems associated with a field carriage by installing a disc under the wheelbase, upon which the gun can rotate a full 360 degrees. While this still limits the gun's ability to track, it allows the guns to fire in any direction with minimal preparation. Furthermore, it retains part of each of the benefits of the field carriage, being weight, space, and complexity.
State and Military funerals
Gun carriages have been used to carry the coffin of a fallen soldiers and officers at military funerals and holders of high office with a military connection in State funerals to their final resting place. The practice has its origins in war and appears in the nineteenth century in the Queens regulations of the British Army.
In the United Kingdom, the visual distinction usually referred to is that in a state funeral, the gun carriage bearing the coffin is drawn by sailors from the Royal Navy rather than horses. (This tradition dates from the funeral of Queen Victoria; the horses drawing the gun carriage bolted, so ratings from the Royal Navy hauled it to the Royal Chapel at Windsor.) This distinguishing feature is not invariable, however, as shown by the use of naval ratings rather than horses at the ceremonial funeral for Lord Mountbatten in 1979 (one of a number of features on that occasion which emphasized Mountbatten's lifelong links with the Royal Navy).
A 12-pounder M1857, the US version of the Canon obusier de 12, showing the block trail which replaced the heavier "double-bracket" carriage.
A British RML 64 pounder 71 cwt gun on a reproduction of a mid-19th century traversing carriage.
French de Bange 155 mm cannon of 1877, with a solid field carriage.
French Canon de 75 modèle 1897
British Ordnance QF 25-pounder gun/howitzer of 1940 with its distinct rotary field carriage.
US 155 mm Long Tom field gun
- Manucy, Albert C (1949), Artillery Through the Ages: A Short Illustrated History of Cannon, National Park Service, Washington DC (pp. 3-5)
- Manucy (pp. 46-51)
- Henry, Chris (2003). British Napoleonic Artillery 1793-1815 (2) Siege and Coastal Artillery. Osprey Publishing Ltd. pp. 16–17. ISBN 1-84176-477-9.
- Manucy (p. 54)
- Manucy (p. 5)
- Dawson, Anthony Leslie (August 2011) [February 2006]. "Some Notes on the Royal Artillery in the Peninsula 1808". www.napoleon-series.org. The Napoleon Series. Retrieved 2 June 2014.
- "trail". Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005. (Subscription or UK public library membership required.)
- Gun carriage in military, state funerals