German submarine U-480

Career (Nazi Germany)
Name: U-480
Ordered: April 10, 1941[1]
Builder: Deutsche Werke, Kiel, yard 311[1]
Laid down: December 8, 1942[1]
Launched: August 14, 1943[1]
Commissioned: October 6, 1943[1]
Fate: Sunk between January 29 and February 20, 1945 in minefield Brazier D2 in the English Channel, with the loss of the entire crew of 48.[1]
General characteristics
Type: Type VIIC submarine
Displacement: 769 tonnes (757 long tons) surfaced
871 t (857 long tons) submerged
Length: 67.1 m (220 ft 2 in) o/a
50.5 m (165 ft 8 in) pressure hull
Beam: 6.2 m (20 ft 4 in) o/a
4.7 m (15 ft 5 in) pressure hull
Draft: 4.74 m (15 ft 7 in)
Propulsion: 2 × supercharged Germaniawerft 6-cylinder 4-stroke M6V 40/46 diesel engines, totalling 2,800–3,200 bhp (2,100–2,400 kW). Max rpm: 470-490
2 × electric motors, totalling 750 shp (560 kW) and max rpm: 296
Speed: 17.7 kn (20.4 mph; 32.8 km/h) surfaced
7.6 knots (8.7 mph; 14.1 km/h) submerged
Range: 15,170 km (8,190 nmi) at 10 kn (19 km/h) surfaced
150 km (81 nmi) at 4 kn (7.4 km/h) submerged
Test depth: 230 m (750 ft)
Crush depth: 250–295 m (820–968 ft)
Complement: 44–52 officers & ratings
Armament: • 5 × 533 mm (21 in) torpedo tubes (4 bow, 1 stern)
• 14 × torpedoes or 26 TMA mines
• 1 × C35 88mm gun/L45 deck gun (220 rounds)
• Various AA guns
Service record
Part of: 5th U-boat Flotilla (October 6, 1943-May 31, 1944)
9th U-boat Flotilla (June 1-October 14, 1944)
11th U-boat Flotilla (October 15, 1944-February 20, 1945)[1]
Identification codes: M 53 621
Commanders: Hans-Joachim Förster
Operations: 1st patrol: June 7-July 7, 1944
2nd patrol: August 3-October 4, 1944
3rd patrol: January 6-February 20, 1945[2]
Victories: 4 ships sunk

U-480 was an experimental Kriegsmarine Type VIIC U-boat of World War II, considered by many to be the first stealth submarine. It was equipped with a special rubber coating (codenamed "Alberich", probably after the German mythological character who had the ability to become invisible) that made it difficult to detect by British ASDIC sonar.

Contents

The coating

The Germans developed a 4-millimetre (0.16 in) thick sheet of synthetic rubber[3] that attenuated sound in the 10 to 18 kHz range to 15% of its normal strength. This frequency range matched the operating range of the early ASDIC active sonar used by the Allies. ASDIC's operating range would have been correspondingly reduced from its optimal range of 2,000 metres (6,600 ft) to somewhere around 300 metres (980 ft). The rubber contained a series of holes, which helped break up sound waves. There were problems with this technology: the material performed differently at different depths, due to the holes being compressed by water pressure, and securing the tiles to the submarine's hull required a special adhesive and careful application. The first tests were conducted in 1940, but it was not used operationally until 1944, with U-480. According to the Naked Science television episode "Stealth Submarine", U-480 had a perforated inner rubber layer covered by a smooth outer one. This formed air pockets with the right separation and size to muffle sonar waves.

World War II service

U-480 made three war patrols, all under the command of Oberleutnant Hans-Joachim Förster. Because of its coating, the ship was sent to the heavily-defended English Channel. The coating worked; U-480 was never detected by sonar.

On its first patrol, the ship was attacked by a Canadian Consolidated PBY Catalina piloted by Laurance Sherman.[1] The aircraft was shot down.[1]

On the second patrol, Förster departed from Brest on August 3, 1944 and sank two warships and two merchantmen:

For his success, Förster was awarded the Knight's Cross of the Iron Cross on 18 October 1944.[4]

U-480 left Trondheim, Norway on January 6, 1945 for its third and last patrol. It did not return. In 1997, the wreck of a Type VIIC U-boat discovered by accident by divers at , 20 kilometres (12 mi) southwest of the Isle of Wight. The following year it was correctly identified as the Alberich coated U480 by nautical archaeologist Innes McCartney. subsequent research by the Naval Historical Branch established that it had fallen victim to the secret minefield Brazier D2 some time between January 29 and February 20. A mine had damaged the tail of U-480, sending it to the bottom 55 metres (180 ft) down. The entire crew of 48 was lost. Helmsman Horst Rösner survived because he had been left behind in Norway for training.

References

  1. ^ a b c d e f g h i "U-480". uboat.net. http://uboat.net/boats/u480.htm. Retrieved April 13, 2011. 
  2. ^ a b "Operations information for U-480". uboatwaffe.net. http://www.ubootwaffe.net/ops/boat.cgi?boat=480. Retrieved April 13, 2011. 
  3. ^ "Anti Sonar Coating / Alberich". uboataces.com. http://www.uboataces.com/sonar-coating.shtml. Retrieved April 15, 2011. 
  4. ^ Scherzer, Veit (2007). Die Ritterkreuzträger Die Inhaber des Ritterkreuzes des Eisernen Kreuzes 1939 von Heer, Luftwaffe, Kriegsmarine, Waffen-SS, Volkssturm sowie mit Deutschland verbündeter Streitkräfte nach den Unterlagen des Bundesarchives (in German). Jena, Germany: Scherzers Miltaer-Verlag. ISBN 978-3-938845-17-2. p. 313

Bibliography

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