The RUR-4 "Weapon Alpha" (originally ''Weapon Able'') was an American

naval A navy, naval force, military maritime fleet, war navy, or maritime force is the branch of a nation's armed forces principally designated for naval and amphibious warfare; namely, lake-borne, riverine, littoral, or ocean-borne combat operatio ...

ahead-throwing anti-submarine rocket launcher. It was designed between 1946 and 1949, and was installed on warships from 1951 to 1969. Unlike

depth charge A depth charge is an anti-submarine warfare (ASW) weapon designed to destroy submarine A submarine (often shortened to sub) is a watercraft capable of independent operation underwater. (It differs from a submersible, which has more limited ...

s, it was designed to attack enemy submarines without requiring the attacking ship to be located directly above the submarine being attacked.

Development

Similar to the earlier American

Mousetrap A mousetrap is a specialized type of animal trap designed primarily to catch and, usually, kill Mouse, mice. Mousetraps are usually set in an indoor location where there is a suspected infestation of rodents. Larger traps are designed to catch ...

, 375mm (14.8") Swedish Bofors, and 250mm (9.8") and 300mm (11.8") Soviet systems, all of which use multiple rockets, Weapon Alpha was developed toward the end of

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

, in response to the German Type XXI

U-boat U-boats are Submarine#Military, naval submarines operated by Germany, including during the World War I, First and Second World Wars. The term is an Anglicization#Loanwords, anglicized form of the German word , a shortening of (), though the G ...

. Begun in a crash program in 1944–5 and put in service before undergoing operational evaluation, it emerged in 1949 as a 227-kg (500 lb) 127mm (5")

rocket A rocket (from , and so named for its shape) is a vehicle that uses jet propulsion to accelerate without using any surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely ...

with a 113-kg (250 lb) warhead that sank at 12 m/s (40 ft/s) (compared to a depth charge, which sank at 2.7–5 m/s (8.9–16.5 ft/s)Fitzsimons, Bernard, ed. "Depth Charge", in ''Encyclopedia of Twentieth Century Weapons and Warfare'' (London: Phoebus Publishing Co, 1978), Volume 7, p. 730.), an influence or

time Time is the continuous progression of existence that occurs in an apparently irreversible process, irreversible succession from the past, through the present, and into the future. It is a component quantity of various measurements used to sequ ...

pistol A pistol is a type of handgun, characterised by a gun barrel, barrel with an integral chamber (firearms), chamber. The word "pistol" derives from the Middle French ''pistolet'' (), meaning a small gun or knife, and first appeared in the Englis ...

, and a range of 360–730 m (400–800 yd). Coupled to the new SQG-1 depth-finding

sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances ( ranging), communicate with or detect objects o ...

(for setting the time fuse, rather than the

hydrostatic Hydrostatics is the branch of fluid mechanics that studies fluids at hydrostatic equilibrium and "the pressure in a fluid or exerted by a fluid on an immersed body". The word "hydrostatics" is sometimes used to refer specifically to water and o ...

pistol of a depth charge), it was to be fired from a revolving Mark 108 launcher (with 22 rounds of ready

ammunition Ammunition, also known as ammo, is the material fired, scattered, dropped, or detonated from any weapon or weapon system. The term includes both expendable weapons (e.g., bombs, missiles, grenades, land mines), and the component parts of oth ...

) at up to twelve rounds per minute. The ready-service

magazine A magazine is a periodical literature, periodical publication, print or digital, produced on a regular schedule, that contains any of a variety of subject-oriented textual and visual content (media), content forms. Magazines are generally fin ...

could not be reloaded while Weapon Alpha was in use. It was replaced by the

RUR-5 ASROC The RUR-5 ASROC (for "Anti-Submarine Rocket") is an all-weather, all sea-conditions anti-submarine missile system. Developed by the United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, ser ...

, which was developed by the

U.S. Navy The United States Navy (USN) is the maritime service branch of the United States Department of Defense. It is the world's most powerful navy with the largest displacement, at 4.5 million tons in 2021. It has the world's largest aircraft ...

in the 1950s. Nonetheless, Weapon Alpha remained in service through the 1960s until supplanted by ASROC.

Gallery

Image:WeaponAlfa.jpg, A dismounted Mk 108 launcher at the Intrepid Sea-Air-Space Museum. File:RUR-4A round.jpg, The RUR-4's rocket round. File:USS Wilkinson (DL-5) launching Weapon Alpha in 1956.jpg, RUR-4 launch from , 1956.

References

Sources

* Fitzsimons, Bernard, ed. ''Encyclopedia of Twentieth Century Weapons and Warfare'' (London: Phoebus Publishing Co, 1978), "Weapon Alpha", Volume 24, p. 2589. * Fitzsimons, Bernard, ed. ''Encyclopedia of Twentieth Century Weapons and Warfare'' (London: Phoebus Publishing Co, 1978), "Mousetrap", Volume 19, pp. 1946-7. * Fitzsimons, Bernard, ed. ''Encyclopedia of Twentieth Century Weapons and Warfare'' (London: Phoebus Publishing Co, 1978), "Depth Charge", Volume 7, p. 730. *
DiGiulian, Tony Navweaps.com US ASW weapons page
{{US military rockets RUR004 RUR004 Explosive weapons RUR004 RUR004 Military equipment introduced in the 1950s Anti-submarine rockets