Hedgehog (weapon)

A hedgehog is a spiny mammal of the subfamily Erinaceinae, in the eulipotyphlan family Erinaceidae. There are seventeen species of hedgehog in five genera found throughout parts of Europe, Asia, and Africa, and in New Zealand by introduction. There are no hedgehogs native to Australia and no living species native to the Americas. However, the extinct genus Amphechinus was once present in North America.

A depth charge is an anti-submarine warfare (ASW) weapon. It is intended to destroy a submarine by being dropped into the water nearby and detonating, subjecting the target to a powerful and destructive hydraulic shock. Most depth charges use high explosive charges and a fuze set to detonate the charge, typically at a specific depth. Depth charges can be dropped by ships, patrol aircraft, and helicopters.

Lieutenant-Colonel Latham Valentine Stewart Blacker OBE was a British Army officer and inventor of weapons; he invented the Blacker Bombard, from which was developed the Hedgehog anti-submarine spigot-mortar – and laid the basis of the PIAT anti-tank weapon.

The Royal Regiment of Artillery, commonly referred to as the Royal Artillery (RA) and colloquially known as "The Gunners", is one of two regiments that make up the artillery arm of the British Army. The Royal Regiment of Artillery comprises thirteen Regular Army regiments, the King's Troop Royal Horse Artillery and five Army Reserve regiments.

Infantry is a military specialization which engages in ground combat on foot. Infantry generally consists of light infantry, mountain infantry, motorized infantry, mechanized infantry, airborne infantry, air assault infantry, and marine infantry.

The Blacker Bombard, also known as the 29-mm Spigot Mortar, was an infantry anti-tank weapon devised by Lieutenant-Colonel Stewart Blacker in the early years of the Second World War.

The Projector, Infantry, Anti Tank (PIAT) Mk I was a British man-portable anti-tank weapon developed during the Second World War. The PIAT was designed in 1942 in response to the British Army's need for a more effective infantry anti-tank weapon and entered service in 1943.

A circle is a shape consisting of all points in a plane that are at a given distance from a given point, the centre. Equivalently, it is the curve traced out by a point that moves in a plane so that its distance from a given point is constant. The distance between any point of the circle and the centre is called the radius. Usually, the radius is required to be a positive number. A circle with is a degenerate case. This article is about circles in Euclidean geometry, and, in particular, the Euclidean plane, except where otherwise noted.

In mathematics, an ellipse is a plane curve surrounding two focal points, such that for all points on the curve, the sum of the two distances to the focal points is a constant. It generalizes a circle, which is the special type of ellipse in which the two focal points are the same. The elongation of an ellipse is measured by its eccentricity , a number ranging from to .

The forecastle is the upper deck of a sailing ship forward of the foremast, or, historically, the forward part of a ship with the sailors' living quarters. Related to the latter meaning is the phrase "before the mast" which denotes anything related to ordinary sailors, as opposed to a ship's officers.

Torpex is a secondary explosive, 50% more powerful than TNT by mass. Torpex comprises 42% RDX, 40% TNT and 18% powdered aluminium. It was used in the Second World War from late 1942, at which time some used the names Torpex and RDX interchangeably, much to the confusion of today's historical researchers. The name is short for torpedo explosive. Torpex proved to be particularly useful in underwater munitions because the aluminium component had the effect of making the explosive pulse last longer, which increased the destructive power. Besides torpedoes, naval mines, and depth charges, Torpex was only used in the Upkeep, Tallboy and Grand Slam bombs as well as the drones employed in Operation Aphrodite. Torpex has long been superseded by H6 and Polymer-bonded explosive (PBX) compositions. It is therefore regarded as obsolete and Torpex is unlikely to be encountered except in old munitions or unexploded ordnance, although a notable exception to this is the Sting Ray lightweight torpedo, which as of October 2020 remains in service with the Royal Navy and several foreign militaries. The German equivalent of Torpex was Trialen.

HMS Westcott (D47) was a Royal Navy Admiralty W-class destroyer that served in the Second World War. In the Second World War Westcott served in an anti-submarine role and escorted numerous Atlantic and Malta convoys.

HMS Ferret was a shore establishment and naval base of the Royal Navy during the Second World War, located in Derry. It was given a ship's name as a stone frigate.

The Kriegsmarine was the navy of Germany from 1935 to 1945. It superseded the Imperial German Navy of the German Empire (1871–1918) and the inter-war Reichsmarine (1919–1935) of the Weimar Republic. The Kriegsmarine was one of three official branches, along with the Heer and the Luftwaffe, of the Wehrmacht, the German armed forces from 1935 to 1945.

An acoustic torpedo is a torpedo that aims itself by listening for characteristic sounds of its target or by searching for it using sonar. Acoustic torpedoes are usually designed for medium-range use, and often fired from a submarine.

The Pacific War, sometimes called the Asia–Pacific War, was the theater of World War II that was fought in eastern Asia, the Pacific Ocean, the Indian Ocean, and Oceania. It was geographically the largest theater of the war, including the vast Pacific Ocean theater, the South West Pacific theater, the Second Sino-Japanese War, and the Soviet–Japanese War.

USS England (DE-635), a Buckley-class destroyer escort of the United States Navy, was named in honor of Ensign John C. England (1920–1941), who was killed in action aboard the battleship Oklahoma during the Japanese attack on Pearl Harbor on 7 December 1941. Her sinking of six Japanese submarines in twelve days is a feat unparalleled in the history of antisubmarine warfare.

USS Solar (DE-221), a Buckley-class destroyer escort of the United States Navy, was named in honor of Boatswain's Mate First Class Adolfo Solar (1900–1941), who was killed in action during the Japanese attack on Pearl Harbor on 7 December 1941.

Sonar is a technique that uses sound propagation to navigate, measure distances (ranging), communicate with or detect objects on or under the surface of the water, such as other vessels.

German submarine U-427 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II.

USS Moberly (PF-63), a Tacoma-class frigate, was the only ship of the United States Navy to be named for Moberly, Missouri.

German submarine U-853 was a Type IXC/40 U-boat of Nazi Germany's Kriegsmarine during World War II. Her keel was laid down on 21 August 1942 by DeSchiMAG AG Weser of Bremen. She was commissioned on 25 June 1943 with Kapitänleutnant Helmut Sommer in command. U-853 saw action during the Battle of the Atlantic in World War II. She conducted three patrols, sinking two ships totalling 5,353 GRT and 430 tons.

USS Silversides (SS/AGSS-236) is a Gato-class submarine, the first ship of the United States Navy to be named for the silversides.

Muskegon, a city in the US. state of Michigan, is the county seat of Muskegon County. Situated around a harbor of Lake Michigan, Muskegon is known for fishing, sailing regattas, and pleasure boating, and as a commercial- and cruise-ship port. It is a popular vacation destination because of the expansive freshwater beaches, historic architecture, and public art collection. It is the most populous city along Michigan's western shore. At the 2020 United States Census, the city's population was 38,318. The southwest corner of Muskegon Township, the city is administratively autonomous.

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.

Limbo, or Anti Submarine Mortar Mark 10, was the final development of the forward-throwing anti-submarine weapon Squid, designed during the Second World War and was developed by the Admiralty Underwater Weapons Establishment in the 1950s.

Mousetrap was an anti-submarine rocket used mainly during World War II by the United States Navy and Coast Guard. Its development began in 1941 as a replacement for Hedgehog, a British-made projector, which was the first forward-throwing ASW weapon. Those, however, were spigot-launched, placing considerable strain on the launching vessel's deck, whereas Mousetrap was rocket-propelled. As a result, Mousetrap's four or eight rails for 7.2-inch (183 mm) rockets saved weight and were easier to install.

The Cold War was a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc. The term cold war is used because there was no large-scale fighting directly between the two superpowers, but they each supported opposing sides in major regional conflicts known as proxy wars. The conflict was based on the ideological and geopolitical struggle for global influence by these two superpowers, following their temporary alliance and victory against Nazi Germany and Imperial Japan in 1945. Aside from the nuclear arsenal development and conventional military deployment, the struggle for dominance was expressed via indirect means such as psychological warfare, propaganda campaigns, espionage, far-reaching embargoes, rivalry at sports events, and technological competitions such as the Space Race.

The Normandy landings were the landing operations and associated airborne operations on Tuesday, 6 June 1944 of the Allied invasion of Normandy in Operation Overlord during World War II. Codenamed Operation Neptune and often referred to as D-Day, it was the largest seaborne invasion in history. The operation began the liberation of France and laid the foundations of the Allied victory on the Western Front.

The Infantry Tank Mark II, best known as the Matilda, was a British infantry tank of the Second World War.

The RBU-6000 Smerch-2 is a 213 mm caliber Soviet anti-submarine rocket launcher. It is similar in principle to the Royal Navy Hedgehog system used during the Second World War. The system entered service in 1960–1961 and is fitted to a wide range of Russian surface vessels. It consists of a horseshoe-shaped arrangement of twelve launch barrels, that are remotely directed by the Burya fire control system. It fires RGB-60 unguided depth charges. The rockets are normally fired in salvos of 1, 2, 4, 8 or 12 rounds. Reloading is automatic, with individual rounds being fed into the launcher by the 60UP loading system from a below deck magazine. Typical magazine capacity is either 72 or 96 rounds per launcher. It can also be used for shore bombardment.

The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against France. The modern Royal Navy traces its origins to the early 16th century; the oldest of the UK's armed services, it is consequently known as the Senior Service.

The Spanish Navy or officially, the Armada, is the maritime branch of the Spanish Armed Forces and one of the oldest active naval forces in the world. The Spanish Navy was responsible for a number of major historic achievements in navigation, the most famous being the discovery of America and the first global circumnavigation by Elcano. For several centuries, it played a crucial logistical role in the expansion and consolidation of the Spanish Empire, and defended a vast trade network across the Atlantic Ocean between the Americas and Europe, and the Manila Galleon across the Pacific Ocean between the Philippines and the Americas.

The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of its active battle fleet alone exceeding the next 13 navies combined, including 11 allies or partner nations of the United States as of 2015. It has the highest combined battle fleet tonnage and the world's largest aircraft carrier fleet, with eleven in service, two new carriers under construction, and five other carriers planned. With 336,978 personnel on active duty and 101,583 in the Ready Reserve, the United States Navy is the third largest of the United States military service branches in terms of personnel. It has 290 deployable combat vessels and more than 2,623 operational aircraft as of June 2019.

The Royal Canadian Navy is the naval force of Canada. The RCN is one of three environmental commands within the Canadian Armed Forces. As of 2021, the RCN operates 12 frigates, four attack submarines, 12 coastal defence vessels, eight patrol class training vessels, two offshore patrol vessels, and several auxiliary vessels. The RCN consists of 8,570 Regular Force and 4,111 Primary Reserve sailors, supported by 3,800 civilians. Vice-Admiral Angus Topshee is the current commander of the Royal Canadian Navy and chief of the Naval Staff.

The United States Coast Guard (USCG) is the maritime security, search and rescue, and law enforcement service branch of the United States Armed Forces and one of the country's eight uniformed services. The service is a maritime, military, multi-mission service unique among the United States military branches for having a maritime law enforcement mission with jurisdiction in both domestic and international waters and a federal regulatory agency mission as part of its duties. It is the largest and most powerful coast guard in the world, rivaling the capabilities and size of most navies.

The Philippine Navy (PN) is the naval warfare service branch of the Armed Forces of the Philippines. It has an estimated strength of 24,500 active service personnel, including the 8,300-strong Philippine Marine Corps. It operates 82 combat vessels, 14 auxiliary vessels, 25 manned aircraft and 8 unmanned aerial vehicles. It shares the responsibility of patrolling the maritime borders with the Philippine Coast Guard, a formerly attached unit which became a separate maritime law enforcement agency in 1998.