The G7es (T5) ''"Zaunkönig"'' ("wren") was a passive

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 sub ...

employed by

German German(s) may refer to: * Germany (of or related to) ** Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...

U-boats U-boats were naval submarines operated by Germany, particularly in the First and Second World Wars. Although at times they were efficient fleet weapons against enemy naval warships, they were most effectively used in an economic warfare rol ...

during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

. 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 A detonator, frequently a blasting cap, is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the last two being the most common. The commercial use of explosives uses electri ...

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 Acoustic homing is a system which uses the acoustic signature (sound) of a target to guide a moving object, such as a torpedo. Acoustic homing can be either passive or active in nature. Using passive homing, the system is designed to move either ...

torpedo was specifically designed as to be attracted by the pitch of an escort's propellers and would — even if aimed inaccurately — explode under the ship's stern. There were three variants: * Two flat-nosed versions which contained four sets of

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 change ...

hydrophones. * A round-nosed version which contained two magnetostriction hydrophones inside a funnel-shaped baffle.

Use

The acoustic homing torpedo required a minimum distance of to lock onto the target after launch. The detection range of the hydrophones varied much according to circumstance, but 450 m (500 yards) was considered reasonable for a ship moving at 15 knots. Campbell (1985). ''Naval Weapons of World War Two'', p. 264 After at least one unconfirmed instance of a U-boat () sinking after being allegedly hit by its own torpedo, and another circle-back that forced the ''

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- ...

'' to crash-dive, the

BdU 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 World War, First and Second World Wars. The term also referred to the Comma ...

ordered the submarines to dive to and go completely silent after launching acoustic torpedoes to minimize the risk. The first 80 T5s were delivered on 1 August 1943, and the weapon was first used in a large-scale maneuver against the North Atlantic

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 ...

in late September 1943. The commanders reported a number of torpedo strikes and recorded the sinking of nine commercial steamers and 12 escort ships after the battle. In fact, only six merchant ships and three escort vessels, a destroyer, a frigate and a corvette were sunk. However, despite some initial success, in particular sinking destroyers and corvettes, the ''Zaunkönig''s effectiveness was quickly nullified by the introduction of a decoy known as ''

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 transatlant ...

'' noise maker. The NDRC worked on countermeasures to an acoustic torpedo long before its introduction by the Germans. At the end of September 1943, it was promptly installed on all transatlantic escort vessels. Grossadmiral

Dönitz Dönitz is a village and a former municipality in the district Altmarkkreis Salzwedel, in Saxony-Anhalt, Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous c ...

, not satisfied with the development of countermeasures, realized that his brief success against the North Atlantic trade convoys was only a flare up and recorded: In spite of highly effective Allied countermeasures, a total of over 700 T5s were fired in combat, sinking 77 ships.

Footnotes

References

* * *

External links

*{{cite web , url=http://uboat.net/technical/torpedoes.htm , title=A brief synopsis of German torpedo evolution during World War II , last=Helgason , first=Guðmundur , website=German U-boats of WWII - uboat.net
More indepth details of G7es (TV) Acoustic Homing Torpedo at uboataces.com
World War II torpedoes of Germany ja:G7 (魚雷)#G7es (TV)

Description

Use

See also

Footnotes

References

External links