Thetis was the name of a floating

radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...

decoy used by German

U-boat U-boats are Submarine#Military, naval submarines operated by Germany, including during the World War I, First and Second World Wars. The term is an Anglicization#Loanwords, anglicized form of the German word , a shortening of (), though the G ...

s during the

Second World War World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. The device was stored dismantled in the bow compartment as a pole about two metres long. Assembly usually took place in the U-boat's conning tower, and could be assembled in about four minutes (''FuMT 2 - Thetis IIC''). Later versions could be launched from a standard torpedo tube (''FuMT 4 - Thetis US''). When deployed, it was extended to a total length of eight metres, half of which was submerged. The upper half had a series of reflectors that were tuned to

Allied An alliance is a relationship among people, groups, or states that have joined together for mutual benefit or to achieve some common purpose, whether or not an explicit agreement has been worked out among them. Members of an alliance are calle ...

anti-submarine radar wavelengths to give the same return signal as a U-boat. The number of Thetis decoys carried varied between different U-boats: * carried approximately 12 units during her 10th and last patrol between 16 January 1944 and 6 May; all were used in the

Bay of Biscay The Bay of Biscay ( ) is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the western coast of France from Point Penmarc'h to the Spanish border, and along the northern coast of Spain, extending westward ...

. * carried 16 units during her 6th and last patrol between 25 January 1944 and 25 February. * carried an unknown number of units during her 21st and last patrol between 23 April 1944 and 4 May. * carried 15 units during her 13th and last patrol between 29 February 1944 and 13 March. U-575 would surface every night and laid a total of 10 on her outward voyage, the remaining units were to have been laid in the same area on her return. * carried 20 units during her 2nd and last patrol between 24 February 1944 and 6 March. U-744 used them on her outward voyage between 11°W and 12°W in the

. The first time the Allies knew about the "Thetis" was in a coded radio message to all U-boats transmitted on 11 January 1944. "Thetis" was introduced in January, when large numbers were released into the Bay of Biscay in July to simulate U-boat patrols during the

Battle of Normandy Operation Overlord was the codename for the Battle of Normandy, the Allied operation that launched the successful liberation of German-occupied Western Europe during World War II. The operation was launched on 6 June 1944 (D-Day) with the N ...

References

*{{cite web , title = HyperWar: Battle of the Atlantic IV: Tech. Intel. from Allied Comm. Intel.

hapter 2 This glossary provides an overview of terms used in the description of lichens, composite organisms arising from algae or cyanobacteria living symbiotically among filaments of multiple fungus species. Erik Acharius, known as the "father of lic ...

, url = http://www.ibiblio.org/hyperwar/ETO/Ultra/SRH-025/SRH025-2.html , accessdate = 2017-04-13 Weapons countermeasures

See also

References