The Squid Was a Deadly ASW Successor to the WWII Hedgehog Mortar

March 31, 2025

The mechanical Squid proved to be particularly deadly to Nazi German Kriegsmarine U-boats and their crews.

In addition to being one of the most intelligent invertebrate species of the Animal Kingdom, the squid is also a voracious oceanic predator. Therefore, it should come as no surprise that this deadly animal would inspire the name of a weapon of naval warfare. (In the mostly good-natured world of interservice rivalries, “squid” is also the slang term for a U.S. Navy sailor, but that’s a discussion topic for a different time and place.)

However, unlike its fellow cephalopods—namely the octopus, cuttlefish, argonaut (aka the “paper nautilus”), and most famously, the chambered nautilus—the squid didn’t have a U.S. Navy submarine named in its honor, but rather a British Royal Navy antisubmarine warfare (ASW) weapon of World War II. Indeed, the Squid was a successor to another Royal Navy ASW weapon that was already a huge improvement over the depth charge, that being the Hedgehog spigot mortar.

The National Interest now takes a deeper dive into the history of the Squid ASW mortar.

Squid Initial History and Specifications

Designed in 1942 by the British Admiralty’s Directorate of Miscellaneous Weapons Development—nicknamed the “Wheezers and Dodgers”—which was the same group of engineering geniuses that designed the aforementioned Hedgehog, the Squid was ordered directly from the drawing board and rushed into official operational service in May 1943 while still technically in the prototype phase, with the destroyer HMS Ambuscade (Pennant No. D38) serving as the first beneficiary/host of the Squid’s services.

As noted by the NavWeps website:

“This weapon was a three-barrel 12 inch (30.5 cm) mortar with the mortars mounted in series, one behind the other, with all three barrels at a fixed elevation. The barrels were mounted in a frame that could be rotated 30 degrees to either side for training and 90 degrees for loading. The barrels were set slightly askew such that their pattern formed a triangle about 40 yards (37 m) on a side at a distance of 275 yards (250 m) ahead of the ship.”

Additional tech specs and vital stats of the Squid were as follows:

Weight: 390 lbs. (177 kgs) overall; 207-lb. (94 kg) minol warhead
Sinking Speed: 43.5 feet per second (13.3 meters per second); a clockwork time fuse was used to set the depth
Maximum Depth: 900 feet (274 meters); all three projectiles had to be set to the same.

In addition to Britain’s Royal Navy, the Royal Canadian Navy, and the Swedish Navy adopted the Squid. However, for whatever reason, neither the U.S. Navy nor the U.S. Coast Guard acquired it; perhaps they were content to stick with the Hedgehog that they had acquired from Britain in 1942.

Squid Operational History and Performance

The mechanical Squid proved to be just as deadly to Nazi German Kriegsmarine U-boats and their crews as its rubbery fleshed and blue-blooded namesake is to fish and crustaceans.

The first production phase unit of the Squid was installed on the corvette HMS Hadleigh Castle (Pennant. No K355); it went on to be installed on seventy frigates and corvettes during the remainder of the war.

The first official Squid kill was scored by the frigate HMS Loch Killin (Pennant. No. K391) (poetically apropos moniker, eh?) on July 31, 1944, when it sank the U-333, although the U-744 was forced to surrender on March 6, 1944, after being damaged by a combo of depth charges and Squids.

The aforementioned NavWeps site credits a total of thirteen submarine kills to the Squid between 1943 and 1945. Mind you, this isn’t as big an aggregate kill tally as at Hedgehog (forty-seven kills) or depth charges (85.5 kills) during that same timeframe. However, when you compare the kill-to-attack ratios of the weapons side-by-side, the proportionate effectiveness of the Squid can be more fully appreciated:

Squid: Thirteen kills out of thirty-eight attacks; a 2.9-to-1 success ratio
Hedgehog: Forty-seven kills out of 268 attacks; a 5.7-to-1 success ratio
Depth Charges: 85.5 kills out of 5,174 attacks; a 60.5-to-1 success ratio

Where Are They Now?

Amazingly, the Squid remained in Royal Navy service up until 1977, with the Type 61 frigate HMS Salisbury (Pennant No. F32) being the last British warship to fire the weapon. Meanwhile, the Swedish Navy used the weapon all the way up until 1982, when their Östergötland-class destroyers were decommissioned.

Squids have been preserved for posterity in at least three locations, namely:

The Maritime Museum Malacca in Malaysia
Destroyer HMS Cavalier (Pennant No. D73/R73), a museum ship at the Chatham Historic Dockyard in Kent, England
Destroyer HMCS Haida (Yard No. 41), a museum ship docked in Hamilton, Ontario, Canada

About the Author: Christian D. Orr

Christian D. Orr was previously a Senior Defense Editor for National Security Journal (NSJ) and 19FortyFive. He is a former Air Force Security Forces officer, Federal law enforcement officer, and private military contractor (with assignments worked in Iraq, the United Arab Emirates, Kosovo, Japan, Germany, and the Pentagon). Chris holds a B.A. in International Relations from the University of Southern California (USC) and an M.A. in Intelligence Studies (concentration in Terrorism Studies) from American Military University (AMU). He has also been published in The Daily Torch, The Journal of Intelligence and Cyber Security, and Simple Flying. Last but not least, he is a Companion of the Order of the Naval Order of the United States (NOUS). If you’d like to pick his brain further, you can ofttimes find him at the Old Virginia Tobacco Company (OVTC) lounge in Manassas, Virginia, partaking of fine stogies and good quality human camaraderie.

Image: Wikipedia.