Disappearing gun

History

Captain (later Colonel Sir) Alexander Moncrieff, improved on existing designs for a gun carriage capable of rising over a parapet before being reloaded from behind cover. His design, based on his observations in the Crimean War was the first widely adopted. The first experimental carriages of this type were wheeled. His key innovation was a practical counterweight system that raised the gun as well as controlled the recoil. Moncrieff promoted his system as an inexpensive and quickly constructed alternative to a more traditional gun emplacement.

The usefulness of such a system had been noted earlier, and experimental designs with raisable platforms or eccentric wheels, with built-in counterweights, were built or proposed. Some used paired guns, in which one cannon acted as the other's counterweight. An unsuccessful attempt at a disappearing carriage was King's Depression Carriage, designed by Rufus King, Jr. of the United States Army in the late 1860s. This used a counterweight to allow a 15-inch (381 mm) Rodman gun to be moved up and down a swiveling ramp, so the weapon could be reloaded, elevated, and traversed behind cover. It was not adopted. Part of a test installation at Fort Foote, Maryland remains. King's design was better suited for breech-loaders; had the US not had a plethora of new muzzle-loaders just after the Civil War it may have seen wider use.

Buffington and Crozier further refined the concept in the late 1880s by allowing the counterweight fulcrum to slide, giving the gun a more elliptical recoil path. The Buffington–Crozier Disappearing Carriage (1893) represented the zenith of disappearing gun carriages, and guns of up to 16-inch size were eventually mounted on such carriages. Disappearing guns were highly popular for a while in the British Empire, the United States and other countries. In the United States, they were the primary armament of the Endicott- and Taft-era fortifications, constructed 1898-1917. Simpler carriages with a limited disappearing function were initially provided for smaller weapons, the balanced pillar for the 5-inch gun M1897 and the Driggs-Seabury masking parapet for the manufacturer's 3-inch gun M1898. However, these could only be retracted at a limited traverse angle, thus could not be used in action, and were disabled during World War I in the "up" position, with new installations receiving pedestal mounts. Both carriage types and their associated guns were removed from service in the 1920s.

Several mobile disappearing mounts appeared in France and Germany circa 1893. These included both road-mobile and rail-mobile designs. In France, Schneider produced a road-mobile design and St. Chamond a rail-mobile design, both for 120 mm (4.7 inch) weapons. The 0.6 meter rail affût-truck system of was used for 120mm and 155mm guns in WWI. Six 120 mm Modèle 1882 guns on St. Chamond mounts were deployed at Fort de Dailly in Switzerland from 1894 to 1939. Krupp produced a rail-mobile 120 mm disappearing gun in 1900.

Though effective against ships, the guns were vulnerable to aerial observation attack. After World War I coastal guns were usually casemated for protection or covered with camouflage for concealment. By 1912, disappearing guns were declared obsolete in the British Army, with only a few other countries, particularly the United States, still producing them up to World War I and retaining them in service until replaced by casemated batteries in World War II.

The only major campaign in which US disappearing guns played a part was the Japanese invasion of the Philippines, which began shortly after the attack on Pearl Harbor on 7 December 1941 and ended with the surrender of US forces on 6 May 1942. The disappearing guns were the least useful of the coast defense assets, as they were positioned to defend against warships entering Manila Bay and Subic Bay and in most cases could not engage Japanese forces due to limited traverse. Despite attempts at camouflage, their emplacements were vulnerable to air and high-angle artillery attack.

Advantages

The disappearing carriage had several principal advantages:

Disadvantages

The disappearing gun had several drawbacks as well:

Gun lift battery

One very uncommon and even more complex type of disappearing gun was Battery Potter at Fort Hancock, Sandy Hook, New Jersey. This and a number of 12-inch barbette emplacements were constructed due to the inability of the early versions of the Buffington-Crozier carriage to accommodate a 12-inch gun. Built in 1892, the battery covered the approaches to New York harbor. Instead of using recoil from the gun to lower the weapon, two 12-inch barbette carriages were placed on individual hydraulic elevators that would raise the 110-ton carriage and gun 14 feet to enable it fire over a parapet wall. After firing, the gun was lowered for reloading using hydraulic ramrods and a shell hoist. While the operation of the battery was slow, taking 3 minutes per shot, its design allowed a 360° field of fire.

Battery Potter required much machinery to operate the gun lifts, including boilers, steam pressure pumps and two accumulators. Due to the inability to generate steam quickly, Battery Potter's boilers were run nonstop during its 14-year life, at significant cost. After the proving of the Buffington-Crozier carriage for 12-inch guns, the United States Army abandoned plans to build several additional gun lift batteries.

Naval artillery

The concept was also attempted for conversion to a naval use. HMS Temeraire was completed in 1877 with two disappearing guns (11-inch muzzle-loading rifles (279 mm)) sinking down into barbette structures (basically circular metal protective walls over which the gun fired when elevated). This was to combine the ability of the early pivot guns to swivel with the protection of more classical fixed naval guns. A similar design was later used in Russia for the first ship of the Ekaterina II-class battleships. It has been suggested that both the harsh saltwater environment and the constant swaying and rolling of a ship at sea caused problems for the complex mechanism.

If the mechanism seemed too temperamental for the open sea, it was not true for rivers and harbors. Armstrong and Mitchell's 1868 HMS Staunch, a gunboat described as a "floating gun carriage", used a single 9inch Armstrong cannon on a lowering platform, and next to no armor. It was a resounding commercial success; there were 21 direct copies, and another six near-sisters. The simplified mounts were intended as much to lower the center of mass as to afford protection, and resembled a "lift battery." The gun was not normally lowered between shots.

Related and Parallel Systems

U.S. Endicott-era balanced pillar and masking parapet mounts were, in a sense, a hybrid of simple pedestal mounts and disappearing mounts: the guns were hidden from observation while out of action, but, once engaged, remained vulnerable to direct observation and direct fire. Since the barrels substantially overlapped the parapet of their installation, it was impossible to point the piece while concealed. The balanced pillar mount was used primarily with the 5-inch gun M1897, while the masking parapet mount was a Driggs-Seabury patent used primarily with the manufacturer's 3-inch gun M1898. During World War I many of these carriages were disabled in the "up" position, and both types and their associated guns were removed from service in the 1920s.

In 1893 Germany's Hermann Gruson developed an armored turret for a 53 mm gun called a "Fahrpanzer" (mobile armor) that had both road- and rail-mobile versions. These were sold to several other countries prior to World War I, notably Switzerland, Romania, and Greece, were widely deployed in that war, and were present in most major Swiss fortifications at least through World War II, including Fort Airolo. Surviving examples of the Fahrpanzer are at the Athens War Museum and the Brussels Army Museum. These mounts were intended for use in prepared trench-type positions that would shelter them from view when retracted; in the Swiss forts they were stored in covered bunkers until readied to fire. While a few units used in fixed fortifications were sometimes mounted on sinking platforms or on short rail stubs intended for tactical concealment, the overwhelming majority were not, and acted in action as completely fixed guns, and are outside the subject of this article.

Retractable turrets were also conceptually similar, but almost never depended on recoil actuation, and, like the balanced pillar systems, often remained visible when actually in operation. Unlike balanced pillar designs, the pieces could generally be pointed and trained from cover, allowing complete surprise for the first shot. They were extensively developed for Continental land defenses, but little used elsewhere.

Australia

Bermuda

Canada

New Zealand

(Armstrong Disappearing Guns)

Philippines

South Africa

Thailand

United Kingdom

United States

(There were several hundred disappearing guns mounted at Endicott Board and Taft Board fortifications in the US; this list only touches on locations with surviving guns, or which saw action, or were otherwise especially noteworthy.)