German submarine U-100 was a Type VIIB U-boat of Nazi Germany's Kriegsmarine during World War II.

Design German Type VIIB submarines were preceded by the shorter Type VIIA submarines. U-100 had a displacement of when at the surface and while submerged. She 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 Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of for use while surfaced, two BBC GG UB 720/8 double-acting electric motors producing a total of for use while submerged. She had two shafts and two propellers. The boat was capable of operating at depths of up to .

The submarine had a maximum surface speed of and a maximum submerged speed of . When submerged, the boat could operate for at ; when surfaced, she could travel at . U-100 was fitted with five torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one SK C/35 naval gun, 220 rounds, and one anti-aircraft gun. The boat had a complement of between 44 and 60.

Service history

First patrol The boat was launched on 10 April 1940, with a crew of 53, under the command of Kapitänleutnant Joachim Schepke. On her first active patrol, U-100 came into contact with two Allied convoys, OA-198 and OA-204. She shadowed both convoys.

Second patrol U-100 departed for her second active patrol on 11 September 1940, coming into contact with the Allied convoy HX 72. HX 72 lost 11 ships in total, with U-100 accounting for 7 ships of 50,340 GRT. In the attack on this convoy, while other U-boats stood off to the side and fired their torpedoes to little or no success, U-100 penetrated inside the convoy before attacking, a tactic soon adopted by the C-in-C of U-boats, Admiral Karl Donitz.

Third patrol After resupplying, U-100 departed for her third active patrol on 12 October 1940. She came into contact with two Allied convoys, HX 79 and SC 7.

Fourth patrol U-100 departed on her fourth patrol on 7 November 1940. On 22 November she came into contact with the Allied convoy SC 11 and began to shadow it.

Fifth patrol U-100 left for her fifth active patrol on 2 December 1940, sinking two vessels from Convoy OB 256, then a third solo vessel.

Sixth and final patrol U-100 departed on her sixth and what would be her final patrol on 9 March 1941. She approached convoy HX 112 from astern in the pre-dawn hours of 17 March, but was detected at a range of 1,000 meters by the Type 286 radar aboard .Rohwer & Hummelchen (1992) p. 54 U-100 was the first U-boat to be so discovered during World War II; she was rammed and sunk by Vanoc while attempting to submerge.Macintyre, Donald, CAPT RN "Shipborne Radar" United States Naval Institute Proceedings September 1967 pp. 78–79 Another destroyer, , was also present.. Six of the boat's 53 crew members survived, spending the remainder of the war as POWs. Schepke was not one of them.

Summary of raiding history Date Ship Flag Tonnage(GRT) Fate16 August 1940Empire Merchant4,864Sunk25 August 1940Jamaica Pioneer5,471Sunk29 August 1940Dalblair4,608Sunk29 August 1940Hartismere5,498Damaged29 August 1940Astra II2,393Sunk29 August 1940Alida Gorthon2,373Sunk29 August 1940Empire Moose6,103Sunk21 September 1940Canonesa8,286Sunk21 September 1940Torinia10,364Sunk21 September 1940Dalcairn4,608Sunk22 September 1940Empire Airman6,586Sunk22 September 1940Scholar3,940Sunk22 September 1940Frederick S. Fales10,525Sunk22 September 1940Simla6,031Sunk18 October 1940Shekatika5,458Damaged18 October 1940Boekelo2,118Damaged19 October 1940Blairspey4,155Damaged20 October 1940Caprella8,230Sunk20 October 1940Sitala6,218Sunk20 October 1940Loch Lomond5,452Sunk23 November 1940Justitia4,562Sunk23 November 1940Bradfyne4,740Sunk23 November 1940Ootmarsum3,628Sunk23 November 1940Bruse2,205Total Loss23 November 1940Salonica2,694Sunk23 November 1940Leise Maersk3,136Sunk23 November 1940Bussum3,636Sunk14 December 1940Kyleglen3,670Sunk14 December 1940Euphorbia3,380Sunk18 December 1940Napier Star10,116SunkSunk:135,614Total loss:2,205Damaged:17,229Total:155,048

References

Bibliography

External links

Canonesa, Convoy HX72 & U-100