A pivot gun was a type of
cannon
A cannon is a large-caliber gun classified as a type of artillery, which usually launches a projectile using explosive chemical propellant. Gunpowder ("black powder") was the primary propellant before the invention of smokeless powder during th ...
mounted on a fixed central emplacement which permitted it to be moved through a wide horizontal arc.
They were a common weapon aboard ships and in land fortifications for several centuries but became obsolete after the invention of
gun turret
A gun turret (or simply turret) is a mounting platform from which weapons can be fired that affords protection, visibility and ability to turn and aim. A modern gun turret is generally a rotatable weapon mount that houses the crew or mechanis ...
s.
History
By mounting a cannon on a pivot, a much wider
arc of fire
The field of fire or zone of fire (ZF) of a weapon, or group of weapons, is the area around it that can easily and effectively be reached by projectiles from a given position.
Field of fire
The term originally came from the ''field of fire'' in f ...
could be obtained than was possible with conventional carriage-mounted cannons. Unlike the latter, however, pivot guns were fixed in one place and could not easily be moved outside of their horizontal arc; they could thus only really be used in fixed positions such as in a fort or on a battleship.
There was no standard size of pivot gun, though they tended to be fairly substantial weapons. Like other cannons, they were usually
muzzleloader
A muzzleloader is any firearm in which the user loads the bullet, projectile and the propellant charge into the Muzzle (firearms), muzzle end of the gun (i.e., from the forward, open end of the gun's barrel). This is distinct from the modern desi ...
s and could fire either
shells or
grapeshot
In artillery, a grapeshot is a type of ammunition that consists of a collection of smaller-caliber round shots packed tightly in a canvas bag and separated from the gunpowder charge by a metal wadding, rather than being a single solid projectile ...
(or other types of shot). Their calibers ranged from a few inches to the giant 11-inch
Dahlgren guns used by the
United States Navy
The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...
in the mid-19th century.
Pivot guns had a major disadvantage in warfare: they were very difficult to protect in battle and were necessarily very exposed, as they lay close to the surface of a ship's deck and required an open field of view. In the late 19th century, large-caliber weapons were replaced by "
disappearing gun
A disappearing gun, a gun mounted on a ''disappearing carriage'', is an obsolete type of artillery which enabled a gun to hide from direct fire and observation. The overwhelming majority of carriage designs enabled the gun to rotate bac ...
s" and ultimately by turrets, which enabled a broad arc of fire while providing the gunners with all-round protection from incoming fire. Smaller guns, particularly
secondary batteries
A rechargeable battery, storage battery, or secondary cell (formally a type of energy accumulator), is a type of electrical battery which can be charged, discharged into a load, and recharged many times, as opposed to a disposable or prima ...
and the primary armament of
cruiser
A cruiser is a type of warship. Modern cruisers are generally the largest ships in a fleet after aircraft carriers and amphibious assault ships, and can usually perform several operational roles from search-and-destroy to ocean escort to sea ...
s and
destroyer
In naval terminology, a destroyer is a fast, maneuverable, long-endurance warship intended to escort
larger vessels in a fleet, convoy, or carrier battle group and defend them against a wide range of general threats. They were conceived i ...
s, retained pivot mountings until the 1920s, when turrets generally replaced them.
Pivot guns should not be confused with
swivel gun
A swivel gun (or simply swivel) is a small cannon mounted on a swiveling stand or fork which allows a very wide arc of movement. Another type of firearm referred to as a swivel gun was an early flintlock combination gun with two barrels that rot ...
s, a much smaller type of ordnance.
Gallery
File:HMS Sidon 68 pounder pivot gun 1855 LOC 05685u.jpg, Sebastopol from the sea - sketched from the deck of HMS ''Sidon''. The men are operating a 68-pounder 88 cwt smoothbore muzzle-loading gun.
File:RBL_7-inch_Armstrong_gun_on_wooden_carriage.jpg, Armstrong 110-pounder rifled breech-loader mounted as a pivot gun on the forecastle of a Royal Navy ship
File:USSWabashPivotGun1855.jpg, Pivot gun crew of USS ''Wabash''
File:Graf Goetzen Kanone.jpg, A 10.5 cm SK L/40 naval gun salvaged from the light cruiser
A light cruiser is a type of small or medium-sized warship. The term is a shortening of the phrase "light armored cruiser", describing a small ship that carried armor in the same way as an armored cruiser: a protective belt and deck. Prior to thi ...
and mounted on the gunboat
A gunboat is a naval watercraft designed for the express purpose of carrying one or more guns to bombard coastal targets, as opposed to those military craft designed for naval warfare, or for ferrying troops or supplies.
History Pre-steam ...
SS ''Graf von Götzen'' during World War I
World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
File:BL5.5inch-50cal-MkI-NavalGun-IWM-August2006.jpg, One of HMS ''Chester''s 5.5-inch guns at the Imperial War Museum
The Imperial War Museum (IWM), currently branded "Imperial War Museums", is a British national museum. It is headquartered in London, with five branches in England. Founded as the Imperial War Museum in 1917, it was intended to record the civ ...
, London
See also
*
Apilan and kota mara
*
Chase gun
*
History of gunpowder
Gunpowder is the first explosive to have been developed. Popularly listed as one of the "Four Great Inventions" of China, it was invented during the late Tang dynasty (9th century) while the Wujing Zongyao, earliest recorded chemical formula f ...
*
Naval artillery in the Age of Sail
The Age of Sail encompasses the period of roughly 1571–1862, when large, sail-powered wooden naval warships dominated the high seas, mounting a large variety of types and sizes of cannon as their main armament. By modern standards, these nav ...
*
Naval tactics in the Age of Sail
Sailing ship tactics were the naval tactics employed by sailing ships in contrast to galley tactics employed by oared vessels. This article focuses on the period from to the mid-19th century, after which sailing warships were replaced with stea ...
References
External links
Sailing ship armaments
{{Early firearms
Naval artillery