PeriscopeA periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer's current position. In its simplest form, it consists of an outer case with mirrors at each end set parallel to each other at a 45° angle. This form of periscope, with the addition of two simple lenses, served for observation purposes in the trenches during World War I. Military personnel also use periscopes in some gun turrets and in armoured vehicles.
Attack submarineAn attack submarine or hunter-killer submarine is a submarine specifically designed for the purpose of attacking and sinking other submarines, surface combatants and merchant vessels. In the Soviet and Russian navies they were and are called "multi-purpose submarines". They are also used to protect friendly surface combatants and missile submarines. Some attack subs are also armed with cruise missiles, increasing the scope of their potential missions to include land targets.
Friedrich Krupp GermaniawerftFriedrich Krupp Germaniawerft (often just called Germaniawerft, "Germania shipyard") was a German shipbuilding company, located in the harbour at Kiel, and one of the largest and most important builders of U-boats for the Kaiserliche Marine in World War I and the Kriegsmarine in World War II. The original company was founded in 1867 but went bankrupt and was bought out by Friedrich Krupp. Krupp was very interested in building warships and in the time before the First World War built a number of battleships for the Kaiserliche Marine, including , , , and .
G7es torpedoThe G7es (T5) "Zaunkönig" ("wren") was a passive acoustic torpedo employed by German U-boats during World War II. It was called the GNAT (German Navy Acoustic Torpedo) by the British. The forerunner of the Zaunkönig was the G7e/T4 Falke, codename "Falcon," which was introduced in March 1943, but saw limited use for trial and was rapidly phased out of service in favor of the later model that received a number of significant enhancements. It was faster, had more range, possessed a magnetic or contact detonator and could be equipped with a percussion pistol.
FoxerFoxer was the code name for a British-built acoustic decoy used to confuse German acoustic homing torpedoes like the G7 torpedo during the Second World War. A US version codenamed FXR was deployed at the end of September 1943 on all transatlantic escort vessels. A Canadian version was also built called the CAAT (Canadian Anti-Acoustic Torpedo) device. It was replaced in US service by the Fanfare noisemaker. The device consisted of one or two noise-making devices towed several hundred metres astern of the ship.
Type 201 submarineThe Type 201 was Germany's first U-boat class built after World War II. They were built out of amagnetic steel to counter the threat of magnetic naval mines, but the material had been insufficiently tested and proved to be problematic in service with the Bundesmarine. Microscopic cracks in the pressure hull forced the cancellation of nine of the twelve ordered submarines and the rebuilding of the first two boats as Type 205 submarines. Responsible for the design and construction was the Ingenieurkontor Lübeck (IKL) headed by Ulrich Gabler.
Submarine warfareSubmarine warfare is one of the four divisions of underwater warfare, the others being anti-submarine warfare, mine warfare and mine countermeasures. Submarine warfare consists primarily of diesel and nuclear submarines using torpedoes, missiles or nuclear weapons, as well as advanced sensing equipment, to attack other submarines, ships, or land targets. Submarines may also be used for reconnaissance and landing of special forces as well as deterrence. In some navies they may be used for task force screening.
Leigh LightThe Leigh Light (L/L) was a British World War II era anti-submarine device used in the Battle of the Atlantic. It was a powerful (22 million candela) carbon arc searchlight of diameter fitted to a number of the British Royal Air Force's Coastal Command patrol bombers to help them spot surfaced German U-boats at night. Early night operations with the new Air-to-Surface Vessel radar (ASV) demonstrated that the radar's minimum range of about meant that the target was still invisible when it disappeared off the radar display.
Type 209 submarineThe Type 209 (U-Boot-Klasse 209) is a range of diesel-electric attack submarines developed exclusively for export by Howaldtswerke-Deutsche Werft of Germany. Five class variants (Types 209/1100, 209/1200, 209/1300, 209/1400 and 209/1500), including modifications thereof, have been successfully exported to 15 countries, with 68 submarines being built and commissioned to five different variants between 1971 and 2021. More boats have been built to modified designs.
High-frequency direction findingHigh-frequency direction finding, usually known by its abbreviation HF/DF or nickname huff-duff, is a type of radio direction finder (RDF) introduced in World War II. High frequency (HF) refers to a radio band that can effectively communicate over long distances; for example, between U-boats and their land-based headquarters. HF/DF was primarily used to catch enemy radios while they transmitted, although it was also used to locate friendly aircraft as a navigation aid.
