Hedgehog (weapon)
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.
| Hedgehog | |
|---|---|
On HMS Westcott, November 1945 | |
| Type | Anti-submarine mortar |
| Place of origin | United Kingdom |
| Service history | |
| In service | 1942 to ? |
| Used by | Royal Navy United States Navy United States Coast Guard Royal Canadian Navy |
| Production history | |
| Designer | Directorate of Miscellaneous Weapons Development |
| Designed | 1941 |
| Specifications | |
| Shell | 65 lb (29 kg) |
| Calibre | 7 in (178 mm) |
| Barrels | 24 |
| Effective firing range | 200–259 m (656–850 ft) |
| Filling | 30 lb (14 kg) TNT or 35 lb (16 kg) Torpex |
Detonation mechanism | Contact |
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. During World War II out of 5,174 British depth charge attacks there were 85.5 kills, a ratio of 60.5 to 1. In comparison, the Hedgehog made 268 attacks for 47 kills, a ratio of 5.7 to 1.