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GNAT (torpedo)
The 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. Description 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. The T5 torpedo was capable of travelling at 24 knots (44 km/h) and had an effective range of about 5000 metres against convoy escorts vessels proceeding at speeds between 10 (18 km/h) and 18 knots (33 km/h). The homing system consisted of two hydrophone receivers and altered the direction of the rudder via an electropneumatic device. The acoustic homing torpedo was specifically designed as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acoustic Torpedo
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 homing). Acoustic torpedoes are usually designed for medium-range use, and often fired from a submarine. The first passive acoustic torpedoes were developed nearly simultaneously by the United States Navy and the Germans during World War II. The Germans developed the G7e/T4 Falke, which was first deployed by the submarines , and in March 1943. Few of these torpedoes were actually used and quickly phased out of service in favor of the T4's successor, the G7es T5 ''Zaunkönig'' torpedo in August 1943. The T5 first saw widespread use in September 1943 against North Atlantic escort vessels and merchant ships in convoys. On the Allied side, the US Navy developed the Mark 24 mine, which was actually an aircraft launched, anti-submarine passive acoustic homing torpedo. The first production Mk. 24s were delivered to the U.S. Navy in Mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Befehlshaber Der U-Boote
The ''Befehlshaber der Unterseeboote'' or BdU (Eng: "Commander of the U-boats") was the supreme commander of the German Navy's U-boat Arm (''Ubootwaffe'') during the First and Second World Wars. The term also referred to the Command HQ of the U-boat arm. The title was established in June 1917, replacing the role of "Leader of the U-boats" (''Führer der Unterseeboote,'' or FdU) for the High Seas Flotillas. The first incumbent was ''Kapitan zur See/Kommodore'' Andreas Michelsen, previously head of the High Seas Fleet’s destroyer force. The post was abolished with the end of the war. It was revived on 17 October 1939, when Karl Dönitz was promoted to rear admiral (''Konteradmiral''). His previous title had been FdU, a position he had held from January 1936. On 31 January 1943 Dönitz was promoted to grand admiral (''Großadmiral'') and became supreme commander (''Oberbefehlshaber der Kriegsmarine'') of the entire Kriegsmarine, replacing Erich Raeder. He retained the title, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of United States Naval Operations In World War II
The ''History of United States Naval Operations in World War II'' is a 15-volume account of the United States Navy in World War II, written by Samuel Eliot Morison and published by Little, Brown and Company between 1947 and 1962. Background Immediately after the attack on Pearl Harbor, Morison, already convinced of the value of personal involvement as a result of sailing experience while writing his biography of Christopher Columbus, wrote to President Roosevelt suggesting the preparation of an official history of the Navy in the war, and volunteering for the task. Both President Roosevelt and the Secretary of the Navy Frank Knox agreed, and in May 1942 Morison was commissioned as a Lieutenant Commander in the United States Naval Reserve, and assigned a staff of assistants, with permission to go anywhere and to see all official records. Morison's reputation as a knowledgeable sailor (based on his analysis in the biography of Christopher Columbus) preceded him, and he was welcom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of World War II Torpedoes Of Germany
List of World War II ''Kriegsmarine'' torpedoes ''Kriegsmarine'' torpedo designation system The first letter indicates the diameter: * G = 53 cm (21 in) * F = 45 cm (17.7 in) * H = 60 cm (23.7 in) * M = 75 cm (30 in) The number indicates the approximate length (for example, the length of the TI is 7163 mm): * 7 = 7 m * 6 = 6 m * 5 = 5 m Next letter(s) indicates specific features regarding propulsion and control: * a = Atem, i.e. Pressluft/Dampfgemisch-Antrieb (pressurized air/steam - "wetheater" - engine) * e = Elektrischer Antrieb (electric engine) * f = Fernlenkung (remote control by radio or cable) * d = Sauerstoff/Dampfgemisch-Antrieb (oxygen/steam engine) * p = Primärbatterie-Antrieb (primary battery propulsion) * m = Verbrennungsmaschine mit Kreislaufverfahren (combustion engine recirculating air) * u = Sauerstoffträger Ingolin spurenfreier Antrieb (oxygen/steam engine with hydrogen peroxide as source for air, and no exposing "b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karl Dönitz
Karl Dönitz (sometimes spelled Doenitz; ; 16 September 1891 24 December 1980) was a German admiral who briefly succeeded Adolf Hitler as head of state in May 1945, holding the position until the dissolution of the Flensburg Government following Germany's unconditional surrender to the Allies days later. As Supreme Commander of the Navy beginning in 1943, he played a major role in the naval history of World War II. He began his career in the Imperial German Navy before World War I. In 1918, he was commanding , and was taken prisoner of war by British forces. While in a POW camp, he formulated what he later called ''Rudeltaktik'' ("pack tactic", commonly called "wolfpack"). By the start of the Second World War, Dönitz was supreme commander of the ''Kriegsmarine'' U-boat arm ( (BdU)). In January 1943, Dönitz achieved the rank of (grand admiral) and replaced Grand Admiral Erich Raeder as Commander-in-Chief of the Navy. Dönitz was the main enemy of Allied naval forces in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Defense Research Committee
The National Defense Research Committee (NDRC) was an organization created "to coordinate, supervise, and conduct scientific research on the problems underlying the development, production, and use of mechanisms and devices of warfare" in the United States from June 27, 1940, until June 28, 1941. Most of its work was done with the strictest secrecy, and it began research of what would become some of the most important technology during World War II, including radar and the atomic bomb. It was superseded by the Office of Scientific Research and Development in 1941, and reduced to merely an advisory organization until it was eventually terminated during 1947. Organization The NDRC was created by an order of President Franklin Delano Roosevelt on June 27, 1940. It was part of the Council of National Defense, which had been created during 1916 to coordinate industry and resources for national security purposes. Vannevar Bush, the director of the Carnegie Institution, had pressed for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foxer
Foxer 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. The noise makers mechanically generated a far louder cavitation noise than the ship's propellers. This noise distracted the acoustic torpedoes away from the rear of the ship into a circling pattern around the noise maker until the torpedo ran out of fuel. The downside of the ''Foxer'' was that it also rendered the ship's own ASDIC ineffective and concealed any other U-boat nearby that could approach the convoy. Nevertheless, the FXR countermeasure proved to be highly effec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convoys ONS 18/ON 202
ONS 18 and ON 202 were North Atlantic convoys of the ONS/ON series which ran during the battle of the Atlantic in World War II. They were the subject of a major U-boat attack in September 1943, the first battle in the ''Kriegsmarine''s autumn offensive, following the withdrawal from the North Atlantic route after Black May. Background Following the defeats of May 1943, and the devastating losses incurred by the U-boat Arm (''U-Bootwaffe'', or UBW) Admiral Dönitz had withdrawn from attacks on the North Atlantic route while awaiting tactical and technical improvements. Chief among these was the T-5 acoustic torpedo, with which (it was planned) the convoy escorts could be attacked and eliminated, leaving the merchant ships defenceless. By September 1943 these were ready, and U-boat Control (''Befehlshaber der Unterseeboote'', BdU) dispatched a patrol group of 21 boats, code-named ''Leuthen'', to renew the attack on the North Atlantic route. Ships involved In September 1943 B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
U-862
German submarine ''U-862'' was a Type IXD2 U-boat of Nazi Germany's ''Kriegsmarine'' during World War II. After Germany's surrender in May 1945, ''U-862'' put into Singapore and was taken over by the Imperial Japanese Navy under the name ''I-502''. ''U-862'' was laid down on 15 August 1942 by DeSchiMAG AG Weser of Bremen. She was commissioned on 7 October 1943 with ''Kapitänleutnant'' Heinrich Timm in command. Timm commanded ''U-862'' for her entire career in ''Kriegsmarine'', receiving a promotion to ''Korvettenkapitän'' on 1 July 1944. ''U-862'' conducted two patrols, sinking seven ships totalling . Design German Type IXD2 submarines were considerably larger than the original Type IXs. ''U-862'' had a displacement of when at the surface and while submerged. The U-boat had a total length of , a pressure hull length of , a beam of , a height of , and a draught of . The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nazi Germany
Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was the German state between 1933 and 1945, when Adolf Hitler and the Nazi Party controlled the country, transforming it into a dictatorship. Under Hitler's rule, Germany quickly became a totalitarian state where nearly all aspects of life were controlled by the government. The Third Reich, meaning "Third Realm" or "Third Empire", alluded to the Nazi claim that Nazi Germany was the successor to the earlier Holy Roman Empire (800–1806) and German Empire (1871–1918). The Third Reich, which Hitler and the Nazis referred to as the Thousand-Year Reich, ended in May 1945 after just 12 years when the Allies defeated Germany, ending World War II in Europe. On 30 January 1933, Hitler was appointed chancellor of Germany, the head of gove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetostriction
Magnetostriction (cf. electrostriction) is a property of magnetic materials that causes them to change their shape or dimensions during the process of magnetization. The variation of materials' magnetization due to the applied magnetic field changes the magnetostrictive strain until reaching its saturation value, λ. The effect was first identified in 1842 by James Joule when observing a sample of iron. This effect causes energy loss due to frictional heating in susceptible ferromagnetic cores. The effect is also responsible for the low-pitched humming sound that can be heard coming from transformers, where oscillating AC currents produce a changing magnetic field. Explanation Internally, ferromagnetic materials have a structure that is divided into '' domains'', each of which is a region of uniform magnetization. When a magnetic field is applied, the boundaries between the domains shift and the domains rotate; both of these effects cause a change in the material's dimensions. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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