Squid (weapon)

Squid
Squid anti-submarine mortar on display at the Devonport Naval Base
Type	Anti-submarine Mortar
Place of origin	United Kingdom
Service history
In service	1943–1977
Used by	Royal Navy Swedish Navy
Production history
Designer	Directorate of Miscellaneous Weapons Development
Designed	1942
Specifications
Weight	10 tons

Shell	440 lb (200 kg)
Calibre	12 in (305 mm)
Barrels	Three
Effective firing range	275 yards (250 m)
Filling	Minol
Filling weight	207 lb (94 kg)
Detonation mechanism	Time fuse

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.

Literally 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 U333; the system was credited with sinking 17 submarines in 50 attacks. By 1959, 195 Squid installations had been produced.

Sailors loading Squid anti-submarine mortar in 1952

This weapon was a three-barrel 12-inch (305 mm) 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 390 pounds (177 kg) with a 207-pound (94 kg) minol charge.^{[Note 1]} On some vessels, the Squid installations were at the stern – the bombs were fired over the length of the ship and dropping into the sea slightly ahead of it.^[1] Sink rate was 43.5 ft/s (13.3 m/s) and a clockwork time fuse 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.^[1] The maximum depth was 900 feet (270 m).

Squid bomb markings diagram

The weapons were automatically fired from the sonar range recorder at the proper moment. The pattern formed a triangle about 40 yards (37 m) on a side at a distance of 275 yards (250 m) 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 25 feet (10 m) above and below the target, the resulting pressure wave crushing the hull of the submarine. Postwar trials found Squid was nine times more effective than conventional depth charges.^[2]

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.^[3]

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. In addition, the system is fitted to HMS Cavalier (D73), which is part of the historic ships collection in the Historic Dockyard in Chatham, Kent.

In Swedish service the system soldiered on untill 1982 when the Östergötland-class destroyers where decommissioned.

Notes

↑ 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.

References

Citations

1 2 "Squid Mortar". Friends of HMCS Haida. Retrieved 21 March 2012.
↑ Zimmerman, David. Great Naval Battle of Ottawa (Toronto: University of Toronto Press, 1989), p.127.
↑ Zimmerman, p.128-9.

Bibliography

Jane's Naval Weapon Systems Issue 33, E R Hooton, ISBN 0-7106-0893-4
Naval Armament, Doug Richardson, 1981, Jane's Publishing, ISBN 0-531-03738-X

External links

Wikimedia Commons has media related to Squid anti-submarine mortar.

British Commonwealth naval weapons of the Second World War

Monitor guns	BL 15 inch

Capital ship main armament	BL 14 inch BL 15 inch BL 16 inch

Heavy cruiser main armament	BL 7.5 inch Mk VI BL 8 inch Mk VIII

Secondary armament and light cruiser main armament	QF 4 inch Mk V QF 4.5 inch QF 5.25 inch BL 6 inch Mk XII BL 6 inch Mk XXII BL 6 inch Mk XXIII

Minesweeper, Sloop, Corvette, Frigate and Destroyer armament	QF 6 pounder 10 cwt QF 12 pdr 12 cwt Mk V QF 4 inch Mk IV BL 4 inch Mk IX QF 4 inch Mk XVI QF 4 inch Mk XIX QF 4.5 inch BL 4.7 inch Mk II QF 4.7 inch Mk IX & XII QF 4.7 inch Mk XI

Submarine guns	QF 12 pdr 12 cwt Mk V QF 3 inch 20 cwt QF 4 inch Mk XII & XXII

Anti-aircraft weapons	Unrotated Projectile Holman Projector 20 mm Oerlikon QF 2 pounder "pom-pom" Mk VIII 40 mm Bofors QF 3-inch 20 cwt QF 4 inch Mk V QF 4 inch Mk XVI QF 4.5 inch QF 4.7 inch Mk VIII

Light weapons	.303 Lewis machine gun .50 Vickers Mk III machine gun QF 3 pounder Vickers

Torpedoes	21 inch Mk VII 21 inch Mk VIII 21 inch Mk X 21 inch Mk XI 24.5 inch Mk I

Anti-submarine weapons	Thornycroft depth charge thrower Hedgehog Squid

Small craft armament	Molins 6 pounder Vickers K machine gun 18 inch torpedo

Foreign-sourced weapons	20 mm Oerlikon 40 mm Bofors 3-inch 23 caliber gun (US) 3-inch 50 caliber gun (US) 4-inch 50 caliber Mark 9 gun (US) 5-inch 51 caliber Mark 8 gun (US) Y-gun depth charge projector (US) Mark 8 torpedo (US)

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