Defensively equipped merchant shipDefensively equipped merchant ship (DEMS) was an Admiralty Trade Division programme established in June 1939, to arm 5,500 British merchant ships with an adequate defence against enemy submarines and aircraft. The acronym DEMS was used to describe the ships carrying the guns, the guns aboard the ships, the military personnel manning the guns, and the shore establishment supporting the system.
Deck gunA deck gun is a type of naval artillery mounted on the deck of a submarine. Most submarine deck guns were open, with or without a shield; however, a few larger submarines placed these guns in a turret. The main deck gun was a dual-purpose weapon used to sink merchant shipping or shell shore targets, or defend the submarine on the surface from enemy aircraft and warships. Typically a crew of three operated the gun, while others were tasked with supplying ammunition. A small locker box held a few 'ready-use' rounds.
High-speed transportHigh-speed transports were converted destroyers and destroyer escorts used in US Navy amphibious operations in World War II and afterward. They received the US Hull classification symbol APD; "AP" for transport and "D" for destroyer. In 1969, the remaining ships were reclassified as "Fast Amphibious Transports", hull symbol LPR. APDs were intended to deliver small units such as Marine Raiders, Underwater Demolition Teams, and United States Army Rangers onto hostile shores.
5-inch/38-caliber gunThe Mark 12 5"/38 caliber gun was a United States dual-purpose naval gun, but also installed in single-purpose mounts on a handful of ships. The 38 caliber barrel was a mid-length compromise between the previous United States standard 5"/51 low-angle gun and 5"/25 anti-aircraft gun. United States naval gun terminology indicates the gun fired a projectile in diameter, and the barrel was 38 calibers long. The increased barrel length provided greatly improved performance in both anti-aircraft and anti-surface roles compared to the 5"/25 gun.
Destroyer escortDestroyer escort (DE) was the United States Navy mid-20th-century classification for a warship designed with the endurance necessary to escort mid-ocean convoys of merchant marine ships. Development of the destroyer escort was promoted by the British need in World War II for anti-submarine ships that could operate in open oceans at speeds of up to 20 knots. These "British Destroyer Escort"s were designed by the US for mass-production under Lend Lease as a less expensive alternative to fleet destroyers.
Liberty shipLiberty ships were a class of cargo ship built in the United States during World War II under the Emergency Shipbuilding Program. Although British in concept, the design was adopted by the United States for its simple, low-cost construction. Mass-produced on an unprecedented scale, the Liberty ship came to symbolize U.S. wartime industrial output. The class was developed to meet British orders for transports to replace ships that had been lost.
KamikazeKamikaze, officially 神風特別攻撃隊, were a part of the Japanese Special Attack Units of military aviators who flew suicide attacks for the Empire of Japan against Allied naval vessels in the closing stages of the Pacific campaign of World War II, intending to destroy warships more effectively than with conventional air attacks. About 3,800 kamikaze pilots died during the war, and more than 7,000 naval personnel were killed by kamikaze attacks. Kamikaze aircraft were essentially pilot-guided explosive missiles, purpose-built or converted from conventional aircraft.
Naval artilleryNaval artillery is artillery mounted on a warship, originally used only for naval warfare and then subsequently used for more specialized roles in surface warfare such as naval gunfire support (NGFS) and anti-aircraft warfare (AAW) engagements. The term generally refers to tube-launched projectile-firing weapons and excludes self-propelled projectiles such as torpedoes, rockets, and missiles and those simply dropped overboard such as depth charges and naval mines. The idea of ship-borne artillery dates back to the classical era.
Anti-aircraft warfareAnti-aircraft warfare, counter-air, anti-air, AA guns, layered air defence or air defence forces is the battlespace response to aerial warfare, defined by NATO as "all measures designed to nullify or reduce the effectiveness of hostile air action". It includes surface based, subsurface (submarine launched), and air-based weapon systems, associated sensor systems, command and control arrangements, and passive measures (e.g. barrage balloons). It may be used to protect naval, ground, and air forces in any location.