Original Item. Only One Available. The Hedgehog (also known as an Anti-Submarine Projector) was a forward-throwing anti-submarine weapon that was used primarily during the Second World War. The device, which was developed by the Royal Navy, fired up to 24 spigot mortars ahead of a ship when attacking a U-boat. It was deployed on convoy escort warships such as destroyers and corvettes to supplement the depth charges. This is an American-manufactured example.

As the mortar projectiles employed contact fuzes rather than time or bathymetric (depth) fuzes, detonation occurred directly against a hard surface such as the hull of a submarine making it more deadly than depth charges, which relied on damage caused by hydrostatic shockwaves.

This is a great example of the fuze and tail assembly of an American-manufactured WWII Hedgehog, an anti-submarine weapon first developed in 1941 for the British Royal Navy. The U.S. saw much success with their variation of the Hedgehog. In the Pacific Theater, the USS England sank six Japanese submarines in a two-week period with the Hedgehog in May 1944. The set has been fully “restored” with a styrofoam replacement warhead for display. The tail assembly still unscrews from the base of the warhead which still appears to be the original base. The side of the original tail shaft is marked:

2.25 IN PROJECTOR ?? TAIL MK 6 MOD 0
BUORD DR 329291
CONTR NO MIXED LOT NO 58
AMC
(BOXED AMERICAN EAGLE?)

This boxed American Eagle may indicate that this was part of a Hedgehog utilized by the United States Navy, which used these extensively at the end of WWII, with the sinking of U-853 using Hedgehogs being well-documented.

With the tail assembly screwed in, the entire piece measures 34¾” tall with the tail assembly having a 7” diameter. The warhead can be removed to inspect the structural interior. The styrofoam warhead has been painted gray with a light blue tip, with fake markings on the sides.

This is a really great display example with a replica warhead, the first example of a Hedgehog we have offered! Comes ready for further research and display.

The "Hedgehog", so named because the empty rows of its launcher spigots resembled the spines on the back of a hedgehog, was a replacement for the unsuccessful Fairlie Mortar that was secretly tested aboard HMS Whitehall in 1941. The Fairlie was designed to fire depth charges ahead of a ship when attacking a submarine. The principle of firing projectiles forwards, instead of dropping depth charges over the stern, was considered viable, despite the failure of the Fairlie. This research by the Directorate of Miscellaneous Weapons Development (DMWD) led to the development of the Hedgehog.

The weapon was a multiple 'spigot mortar' or spigot discharger, a type of weapon developed between the wars by Lieutenant Colonel Stewart Blacker, RA. The spigot mortar was based on early infantry trench mortars. The spigot design allowed a single device to fire warheads of different sizes. 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 1.1-inch (29 mm) Spigot Mortar and the later PIAT anti-tank weapon.

The adaptation of the bombard for naval use was made in partnership with MIR(c) under Major Millis Jefferis, who had taken Blacker's design and brought it into use with the Army. The weapon fires a salvo of 24 bombs in an arc, aimed to land in a circular or elliptical 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 system was developed to solve the problem of the target submarine disappearing from the attacking ship's ASDIC when closer than the sonar's minimum range. The speed of sound in water was such that the time taken for the 'ping' echo to return to the attacking ship from a close by target submarine became too short to allow the human operator to distinguish the returning audible echo from the initial sound pulse emitted by the sonar – the so-called "instantaneous echo", where the output sound pulse and returning echo merge, with the submarine still out of depth charge range. A submarine in this "blind spot" became effectively invisible to the sonar, allowing it to make evasive manoeuvres undetected. The solution was a weapon mounted on the foredeck that discharged the projectiles up and over the ship's bow while the submarine was still detectable by the sonar, entering the water some distance in front of the ship.