Hedgehog (weapon)
Encyclopedia
- This is not to be confused with the animal HedgehogHedgehogA hedgehog is any of the spiny mammals of the subfamily Erinaceinae and the order Erinaceomorpha. There are 17 species of hedgehog in five genera, found through parts of Europe, Asia, Africa, and New Zealand . There are no hedgehogs native to Australia, and no living species native to the Americas...
. - For the area denial weapon, see Czech hedgehogCzech hedgehogThe Czech hedgehog or ježek, was a static anti-tank obstacle defence made of angled iron deployed during World War II by various combatants....
.
The Hedgehog (also known as an Anti-Submarine Projector) was an anti-submarine weapon
Anti-submarine weapon
An anti-submarine weapon is any one of a range of devices that are intended to act against a submarine, and its crew, to destroy the vessel or to destroy or reduce its capability as a weapon of war...
developed by the Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, that was deployed on convoy
Convoy
A convoy is a group of vehicles, typically motor vehicles or ships, traveling together for mutual support and protection. Often, a convoy is organized with armed defensive support, though it may also be used in a non-military sense, for example when driving through remote areas.-Age of Sail:Naval...
escort warship
Warship
A warship is a ship that is built and primarily intended for combat. Warships are usually built in a completely different way from merchant ships. As well as being armed, warships are designed to withstand damage and are usually faster and more maneuvrable than merchant ships...
s such as destroyer
Destroyer
In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...
s to supplement the depth charge
Depth charge
A depth charge is an anti-submarine warfare weapon intended to destroy or cripple a target submarine by the shock of exploding near it. Most use explosives and a fuze set to go off at a preselected depth in the ocean. Depth charges can be dropped by either surface ships, patrol aircraft, or from...
. The weapon worked by firing a number of small spigot mortar bomb
Bomb
A bomb is any of a range of explosive weapons that only rely on the exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy...
s from spiked fittings. Rather than working on a time or depth fuse like depth charges, the bombs exploded on contact and achieved a higher sinking rate against submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...
s than depth charges did.
The Hedgehog received its name because when unloaded, the rows of empty spigots resembled the spines of a hedgehog
Hedgehog
A hedgehog is any of the spiny mammals of the subfamily Erinaceinae and the order Erinaceomorpha. There are 17 species of hedgehog in five genera, found through parts of Europe, Asia, Africa, and New Zealand . There are no hedgehogs native to Australia, and no living species native to the Americas...
.
It was developed by the Directorate of Miscellaneous Weapons Development
Directorate of Miscellaneous Weapons Development
The Directorate of Miscellaneous Weapons Development , known colloquially as the Wheezers and Dodgers, was a department of the Admiralty responsible for the development of various unconventional weapons during World War II...
based on the British Army's Blacker Bombard
Blacker Bombard
The Blacker Bombard, also known as the 29mm Spigot Mortar, was an infantry anti-tank weapon devised by Lieutenant-Colonel Stewart Blacker in the early years of the Second World War.-Development:...
and entered service in 1942.
Hedgehog was replaced in new construction for the Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
by the Squid
Squid (weapon)
Squid was a British World War II ship-mounted anti-submarine weapon. It consisted of a three-barrelled mortar which launched depth charges. It replaced the Hedgehog system, and was in turn replaced by the Limbo system....
mortar in 1943. Squid was in turn replaced by the three-barreled Limbo
Limbo (weapon)
Limbo, or Anti Submarine Mortar Mark 10 , was the final British development of a forward-throwing anti-submarine weapon originally designed during the Second World War. Limbo, a three-barreled mortar similar to the earlier Squid that it superseded, was developed by the Admiralty Underwater Weapons...
. The United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
produced a rocket version of Hedgehog called Mousetrap
Mousetrap (weapon)
Mousetrap was an anti-submarine rocket used mainly during the Second World War by the U.S. Navy and the U.S. Coast Guard. Its development was begun in 1941 as a replacement for Hedgehog, a British-made projector, which was the first ahead-throwing ASW weapon...
. The United States developed Weapon Alpha
Weapon Alpha
The RUR-4 "Weapon Alpha" was an American naval ahead-throwing ASW rocket launcher.Similar to the earlier American Mousetrap, 375mm Swedish Bofors, and 250mm and 300mm Soviet systems, all of which use multiple rockets, Weapon Alpha was developed toward the end of World War II, in response to the...
as a replacement for Hedgehog and Mousetrap. Hedgehog remained in service with the United States Navy into the cold war
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
until both Hedgehog and the less satisfactory Weapon Alpha were replaced by ASROC
ASROC
ASROC is an all-weather, all sea-conditions anti-submarine missile system. Developed by the United States Navy in the 1950s, it was deployed in the 1960s, updated in the 1990s, and eventually installed on over 200 USN surface ships, specifically cruisers, destroyers, and frigates...
.
The Hedgehog was adapted into a 7 shot launcher form for use on the back of the Matilda tank
Matilda tank
The Infantry Tank Mark II known as the Matilda II was a British infantry tank of the Second World War. It was also identified from its General Staff Specification A12....
serving with Australian forces.
From 1949, a copy of Hedgehog was produced in the USSR as MBU-200, developed in 1956 into MBU-600 with enhanced range of 600 m.
Description
Technically the weapon was a multiple 'spigot mortar' or spigot discharger, a type of weapon developed in the interwar period by Lt-Col BlackerStewart Blacker
Lieutenant-Colonel Latham Valentine Stewart Blacker OBE was a British Army officer and inventor of weapons.He invented the Blacker Bombard, laid the basis of the PIAT - both based on the spigot mortar - and the Ayre Petard...
, RA
Royal Artillery
The Royal Regiment of Artillery, commonly referred to as the Royal Artillery , is the artillery arm of the British Army. Despite its name, it comprises a number of regiments.-History:...
. The spigot mortar was based on early infantry
Infantry
Infantrymen are soldiers who are specifically trained for the role of fighting on foot to engage the enemy face to face and have historically borne the brunt of the casualties of combat in wars. As the oldest branch of combat arms, they are the backbone of armies...
trench mortars. By using a spigot, the warhead and barrel size were no longer dependent in the design. The propelling charge was part of the main weapon and worked against a rod (the spigot) set in the baseplate which fitted inside a tubular tail of the 'bomb'. This principle was first used on the Blacker Bombard
Blacker Bombard
The Blacker Bombard, also known as the 29mm Spigot Mortar, was an infantry anti-tank weapon devised by Lieutenant-Colonel Stewart Blacker in the early years of the Second World War.-Development:...
and the later PIAT
PIAT
The Projector, Infantry, Anti Tank was a British hand-held anti-tank weapon developed during the Second World War. The PIAT was designed in 1942 in response to the British Army's need for a more effective infantry anti-tank weapon, and entered service in 1943.The PIAT was based on the spigot...
anti-tank weapon.
The adaptation of the bombard for naval use was made in partnership with MIR(c) under Major Millis Jefferis
Millis Jefferis
Major-General Sir Millis Rowland Jefferis KBE MC was, during the Second World War, the founder of a special unit of the British Ministry of Supply which developed unusual weapons.-Early career:...
who had taken Blacker's design and brought it into use with Army.
The weapon fires a salvo of 24 bombs in an arc, aimed to land in a circular
Circle
A circle is a simple shape of Euclidean geometry consisting of those points in a plane that are a given distance from a given point, the centre. The distance between any of the points and the centre is called the radius....
or elliptical
Ellipse
In geometry, an ellipse is a plane curve that results from the intersection of a cone by a plane in a way that produces a closed curve. Circles are special cases of ellipses, obtained when the cutting plane is orthogonal to the cone's axis...
area about 100 feet (30 m) in diameter at a fixed point about 250 yards (230 m) directly ahead of the attacking ship. The mounting initially was fixed but was later replaced by a gyro-stabilised one to allow for the rolling and pitching of the attacking ship.
The launcher had 4 "cradles", each with 6 launcher spigots. The firing sequence was staggered so all the bombs would land at about the same time. This had the added advantage of minimising the stress on the weapon's mounting, so that deck reinforcement was not needed, and the weapon could easily be retrofitted to any convenient place on a ship. Reloading took about 3 minutes.
The Hedgehog had four key advantages over the depth charge:
- An unsuccessful attack does not hide the submarine from sonarSonarSonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...
.- When a depth charge explodes it can take 15 minutes before the disturbance can settle down enough that sonar becomes effective. Many submarines escaped during the time after an unsuccessful depth charge attack. Since Hedgehog charges only explode on contact, if they miss, the submarine can still be tracked by sonar.
- The depth of the target does not need to be known.
- Proximity weapons (such as depth charges) need to be set for the target's correct depth to be effective. Contact fused charges don't have that limitation. In addition, any explosion indicates a 'hit'.
- The weapon gives no warning of the attack.
- Until depth-finding sonar became available (the first was the Royal NavyRoyal NavyThe Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
's 'Q' attachment in 1943), there was a 'dead period' during the final moments of the attack when the attacker had no knowledge of what the target was doing. U-boat commanders became adept at sharp changes of direction and speed at these moments, thus making the attack less accurate. Ahead-thrown weapons such as Hedgehog did not give the target the necessary warning of when to dodge.
- Until depth-finding sonar became available (the first was the Royal Navy
- A direct hit by 1 or 2 Hedgehog bombs was usually sufficient to sink a submarine.
- Many depth charges were required in order to inflict enough cumulative damage to sink a submarine; even then, many U-boats survived hundreds of detonations over a period of many hours—678 depth charges were dropped against U 427Unterseeboot 427German submarine U-427 was a Type VIIC U boat of the German Kriegsmarine during World War II.Built by Danziger Werft, Danzig, the U-boat was laid down on 27 July 1942, and launched on 6 February 1943, with a crew of 53 under their Austrian commander Oberleutnant Graf Carl-Gabriel von Gudenus. It...
in April 1945. The depth charge, usually exploding at a distance from the submarine, had a cushion of water between it and the target which rapidly dissipated the explosive shock. The Hedgehog's contact charge, on the other hand, had the cushion on the other side, actually increasing the explosive shock. However near-misses with the Hedgehog did not cause cumulative damage as depth charges did; nor did it have the same psychological effect as a depth charge attack.
- Many depth charges were required in order to inflict enough cumulative damage to sink a submarine; even then, many U-boats survived hundreds of detonations over a period of many hours—678 depth charges were dropped against U 427
The Hedgehog became much more successful than depth-charge attacks (the best kill rate was about 25% of attacks whereas depth charges never achieved more than 7%). It initially had a very poor record, although many of the factors had nothing to do with the design of the weapon. USS England
USS England (DE-635)
USS England , a of the United States Navy, was named in honor of Ensign John C. England , who was killed in action aboard the battleship during the Japanese attack on Pearl Harbor on 7 December 1941...
sank six Japanese submarines in a matter of days with Hedgehog in May 1944.
General characteristics
For a single bomb- Calibre: 7 in (178 mm)
- Weight: 65 lb (29 kg)
- Shell Diameter : 7.2 inches
- Shell Length: 3 feet 10.5 inches
- Explosive charge: 30 lb TNT or 35 lb (16 kg) TorpexTorpexTorpex is a secondary explosive 50% more powerful than TNT by mass. Torpex is composed of 42% RDX, 40% TNT and 18% powdered aluminium. It was used in the Second World War from late 1942. The name is short for Torpedo Explosive', having been originally developed for use in torpedoes...
- Range: about 250 yards (200 to 259 m)
- Sinking speed: 22 to 23.5 ft/s (6.7 to 7.2 m/s)
- FuseFuse (explosives)In an explosive, pyrotechnic device or military munition, a fuse is the part of the device that initiates function. In common usage, the word fuse is used indiscriminately...
: Contact, High Explosive - Firing Order: Ripple in pairs, one every tenth of a second
- Reload Time: ~3 minutes
Variants
- Mark 10: elliptical pattern measuring about 140 x 120 feet to a range of 200 yards
- Mark 11: circular pattern measuring 200 feet in diameter out to a range of about 188 yards.
- Mark 15: pattern as for the Mark 11 but mounted on a platform adapted from that of a quadruple 40 mm Bofors gun mount. The Mark 15 could be fired remotely from the ship's plotting room.
See also
- Hedgerow, a land version of Hedgehog for exploding landmines as used on landing craft during the D-Day invasion.
- The Blacker BombardBlacker BombardThe Blacker Bombard, also known as the 29mm Spigot Mortar, was an infantry anti-tank weapon devised by Lieutenant-Colonel Stewart Blacker in the early years of the Second World War.-Development:...
and PIATPIATThe Projector, Infantry, Anti Tank was a British hand-held anti-tank weapon developed during the Second World War. The PIAT was designed in 1942 in response to the British Army's need for a more effective infantry anti-tank weapon, and entered service in 1943.The PIAT was based on the spigot...
infantry anti-tank weapons and the Churchill AVRE's PetardChurchill tankThe Tank, Infantry, Mk IV was a heavy British infantry tank used in the Second World War, best known for its heavy armour, large longitudinal chassis with all-around tracks with multiple bogies, and its use as the basis of many specialist vehicles. It was one of the heaviest Allied tanks of the war...
demolition gun also use the spigot discharger principle., accidentally destroyed by a dropped Hedgehog charge.