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.

Development

Ordered directly from the drawing board in 1942, under the auspices of the Directorate of Miscellaneous Weapons Development, this weapon was rushed into service in May 1943 on board HMS ''Ambuscade''. The first production unit was installed on HMS ''Hadleigh Castle''; it went on to be installed on 70 frigates and corvettes during the Second World War. The first successful use was by HMS ''Loch Killin'' on 31 July 1944, when she sank . The system was credited with sinking 17 submarines in 50 attacks over the course of the war - a success ratio of 2.9 to 1. In contrast, out of 5,174 British depth charge attacks in WWII there were 85.5 kills, a ratio of 60.5 to 1. The Hedgehog made 268 attacks for 47 kills, a ratio of 5.7 to 1. By 1959, 195 Squid installations had been produced.

This weapon was a three-barrel mortar with the mortars mounted in series but off-bore from each other in order to scatter the projectiles. The barrels were mounted in a frame that could be rotated through 90 degrees for loading. The projectiles weighed with a minol charge.Due to shortages of TNT and RDX (cyclonite) in World War II, the British used a 50/50 mixture of ammonium nitrate and TNT (amatol) in naval mines and depth charges. This low-grade explosive was later improved by the addition of about 20% aluminium powder, producing '' minol''. On some vessels, the Squid installations were at the stern – the bombs were fired over the length of the ship and dropped into the sea slightly ahead of it. Sink rate was 43.5 ft/s (13.3 m/s) and a clockwork time fuze was used to determine the detonation depth. All three projectiles had to be set to the same depth; this could be continuously updated right up to the moment of launch to take into account the movements of the target. The maximum depth was .

The weapons were automatically fired from the sonar range recorder at the proper moment. The pattern formed a triangle about on a side at a distance of ahead of the ship. Most Squid installations utilised two sets of mortars. All six bombs were fired in salvo so they formed opposing triangular spreads. The salvos were set to explode above and below the target, the resulting pressure wave crushing the hull of the submarine. Post-war trials found Squid was nine times more effective than conventional depth charges.

Use

Despite its proven effectiveness, some officers, notably Captain Kenneth Adams, RCN, opposed fitting Squid to escorts because it meant sacrificing guns, which would make ships unsuitable for fleet actions.

In April 1977, the Type 61 frigate ''Salisbury'' became the last ship to fire Squid in Royal Navy service. Examples of the mortars are on display at the Explosion! Museum of Naval Firepower in Gosport, Hampshire and another at Devonport Naval Base. The system is fitted to , which is part of the historic ships collection in the Historic Dockyard in Chatham, Kent. It can also be seen on , which is on display in Hamilton, Ontario and at the naval museum in Malacca, Malaysia.

In Swedish service the system soldiered on until 1982 when the ''Östergötland''-class destroyers were decommissioned.

Gallery

Notes

References

Citations

Bibliography

* ''Jane's Naval Weapon Systems'' Issue 33, E R Hooton,
* ''Naval Armament'', Doug Richardson, 1981, Jane's Publishing,

{{DEFAULTSORT:Squid (Weapon)
Explosive weapons
Anti-submarine mortars
Naval weapons of the United Kingdom
World War II naval weapons of the United Kingdom
World War II mortars
305 mm artillery
Weapons and ammunition introduced in 1943