Disappearing gun

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The disappearing gun of the South Battery, at North Head in Devonport, New Zealand.

Diagrams of typical Buffington-Crozier disappearing gun carriage model 1896 which was used extensively in US coastal emplacements. Shown in up position for firing.

A disappearing gun emplacement at Henry Head Battery, La Perouse, New South Wales, Australia.

A Henry Head emplacement from inside.

A disappearing gun is a type of (mainly coastal) artillery, which can be retracted (or recoils after firing) into a protected housing or bunker. It is now mostly historical. The advantages of the system were concealment and cover from enemy fire, especially during the reloading stage. The gun was usually moved into the pit or protective housing by force of the shot's recoil, and was raised again by releasing energy stored in a hinged counterweight. Some also used compressed air,^[1] while a few were built to be raised by steam.^[2]

[edit] History

[edit] Overview

Disappearing guns as a functioning concept were invented in the 1860s by Captain Colin Scott Moncrieff who built on his experience in the Crimean War to improve on existing designs for a gun carriage capable of rising over a parapet before being reloaded behind cover. Using a counterweight system to raise the gun as well as control the recoil, he promoted his 'Protected Barbette System' as an inexpensive and quickly constructed alternative to a more traditional gun emplacement.^[3]

This idea was substantially enhanced by Buffington and Crozier,^[4] with the systems involved soon getting very elaborate, with hydro-pneumatic recoil-control appearing in the 1880s to assist the counterweight action. Disappearing 'carriages' tended to be extremely ponderous and complicated, with surviving records indicating a rate of fire of 1 per 1 to 2 minutes on a 8-inch (20 cm) gun, far slower than less complicated guns. Their size and complexity also made them very expensive.^[1] On the positive side, the guns in their simple pits were, at least initially, much more cost-effective than the previous practice of constructing a whole gun fortification.^[4]

A series of Royal Navy/New Zealand Division of the Royal Navy trials carried out in New Zealand (where numerous disappearing guns had been bought and installed during the Russian Scares), revealed the virtual impossibility of a small shore installation being hit by a warship, except by chance.^[1] With their protective benefits thus cast into doubt, no further production of the expensive disappearing gun carriages was therefore undertaken.

Though effective against ships, they were still quite vulnerable to air strikes, and after World War I, batteries of disappearing guns were usually casemated or covered with camouflage for protection instead.^[5] The carriages were also never able to elevate high enough (maximum limits were generally reached at 20 degrees) and thus useless for the more powerful long-range guns that were coming into service.^[4]

By 1912, the guns were declared obsolete in the British Army, with only some other countries, particularly the United States, still producing them up to World War I^[1] and keeping them active through to the end of World War II.^[4]

[edit] Gun lift battery

One unique type and even more complex type of disappearing gun, its first example named Potter Battery, was built on Sandy Hook, New Jersey in 1892, covering 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 elevator and gun 14 feet to above a parapet wall to fire. Afterwards, it was lowered for reloading which used hydraulic ramrods and a shell hoist. While the operation of the battery was slow, taking 3 minutes per shot, its design allowed an unlimited field of fire.^{[citation needed]}

Battery Potter required a huge amount of machinery to operate the gun lifts, including boilers, steam pressure pumps and two accumulators. Due to the inability to generate steam quickly, Potter's boilers were run nonstop during its 14 year life, adding to its significant cost. After the proving of the Buffington Cozer carriage, the United States Army abandoned plans to build several additional gun lift batteries.^{[citation needed]}

[edit] Naval application

At least once, the concept was also attempted for conversion to a real naval use. The HMS Temerarie was built in 1877 equipped with two disappearing gun turrets 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. However, the design was not successful and apparently never repeated. It is thought that both harsh saltwater environment and the constant swaying and rolling of a ship at sea were to blame for problems with the complex mechanism.^[4] In any case, gun turrets soon afterwards entered naval service, making the idea moot.

[edit] See also

The mount for an 8-inch (20 cm) disappearing gun at South Channel Fort showing the hinged retraction mechanism, Victoria, Australia.

• Coastal artillery
• Seacoast Defense (US)
• Specific installations
  • Battery Chamberlin, home of one of the few remaining disappearing guns in the US
  • Fort Casey, Washington, USA with two of the few remaining disappearing guns in the US
  • Fort Hancock, Sandy Hook, protecting the New York Harbor, USA, location of the world's only steam hydraulic disappearing gun battery
  • Fort Queenscliff, Port Phillip, Australia, coastal defence fortification with a recovered gun from South Channel Fort
  • South Channel Fort, Port Phillip, Australia, coastal defence fortification
  • Fort Scratchley, Newcastle, Australia, coastal defence fortification
  • Henry Head Battery, Sydney, Australia, coastal defence fortification
  • North Head, New Zealand, one remaining gun barrel with partial carriage
  • Fort Jervois, New Zealand, one mostly intact 6-inch and one working-order 8-inch gun
  • Fort Wint, Grande Island, Subic Bay, Luzon, Philippines, coastal defence fortification
  • Flagstaff Hill Fort, Wollongong, Australia, coastal defence fortification
  • Flat Holm, Bristol Channel, Wales, United Kingdom

[edit] References