German submarine U-99 was a Type VIIB U-boat of Nazi Germany's Kriegsmarine during World War II. She was laid down on 31 March 1939 at the Friedrich Krupp Germaniawerft in Kiel as yard number 593. She was launched on 12 March 1940 under the command of Korvettenkapitän Otto Kretschmer and was assigned to the 7th U-boat Flotilla based in Kiel and later in St Nazaire.

U-99 was one of the most successful German U-boats in the war, sinking 38 ships for a total tonnage of of Allied shipping in eight patrols. She damaged five more ships and took one vessel as a prize. U-99 was sunk on 17 March 1941 by British destroyer HMS Walker while attacking convoy HX 112.

Design German Type VIIB submarines were preceded by the shorter Type VIIA submarines. U-99 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-99 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 From April to June 1940, the crew of U-99 were under training, based at Kiel and St. Nazaire.

First patrol On 18 June, U-99 departed Kiel for operations in the North Sea west of Norway. An Arado Ar-196 seaplane from the German battlecruiser attacked her, having mistaken her for a British submarine. Two days later, U-99 was attacked by two aircraft; minor damage was inflicted. She returned to Kiel on 25 June.

Second patrol U-99 departed Wilhelmshaven on 27 June to patrol southwest of Ireland. On 29 June, she was attacked by British aircraft. A crash dive was carried out with the result that the boat hit the seabed, causing some damage which was able to be repaired. On this patrol U-99 sank six ships and captured one, the Estonian cargo steamship Merisaar, carrying a load of timber from New Orleans, to Cork, Ireland. An attack on the was called off on 7 July, when the defensively equipped merchant ship returned fire. On 8 July, over 100 depth charges were dropped by the escorts of Convoy HX 53, but U-99 escaped undamaged. The patrol ended on 21 July.

Date Ship Nationality TonnageMerchant ship tonnages are in gross register tons. Military vessels are listed by tons displacement. Fate5 July 1940 Magog †2,053 Sunk 7 July 1940 Bissen1,514 Sunk5,360 Escaped Sea Glory1,964 Sunk8 July 1940 Humber Arm ‡5,758 Sunk12 July 1940 Ia4,860 Sunk Merisaar*2,136 Captured as prize18 July 1940 Woodbury4,434 Sunk

† Convoy HX 52, ‡ Convoy HX 53, * sunk by German bombing, 15 July 1940

Third patrol On 25 July, U-99 departed Lorient for the North Atlantic. Four ships were sunk and three others damaged. On the 31st, the escorts of Convoy OB 191 dropped 20 depth charges on the boat without effect. Later that evening, a flying boat also attacked her, again without causing any damage. The patrol ended on 5 August.

Date Ship Nationality TonnageMerchant ship tonnages are in gross register tons. Military vessels are listed by tons displacement. (GRT) Fate 28 July 1940 Auckland Star13,212 Sunk 29 July 1940 Clan Menzies7,336 Sunk 31 July 1940 Jamaica Progress5,475 Sunk Jersey City †6,322 Sunk 2 August 1940 Alexia †, ‡8,016 Damaged Lucerna †, ‡6,556 Damaged Strinda †, ‡10,973 Damaged

† Convoy OB 191, ‡ Damaged

Fourth patrol U-99 departed Lorient on 4 September for the North Atlantic; seven ships were sunk. The patrol ended on the 25th. U-99 was slightly damaged in an air raid on Lorient on 27 September.

Date Ship Nationality TonnageMerchant ship tonnages are in gross register tons. Military vessels are listed by tons displacement. (GRT) Fate 11 September 1940 Albionic2,468 Sunk 15 September 1940 Kenordoc †1,780 Sunk 16 September 1940 Lotos † 1,327 Sunk 17 September 1940 ‡2,372 Sunk21 September 1940 Baron Blythswood *3,668 Sunk Elmbank *5,156 Sunk Invershannon*9,154 Sunk

† Convoy SC 3, ‡ Convoy HX 71, * Convoy HX 72

Fifth patrol On 13 October, U-99 departed Lorient to patrol the North West Approaches. Six ships from Convoy SC 7 were sunk and another was damaged. The patrol ended on 22 October.

Date Ship Nationality TonnageMerchant ship tonnages are in gross register tons. Military vessels are listed by tons displacement. (GRT) Fate18 October 1940 6,055 Sunk 4,815 Sunk Niritos3,854 Sunk19 October 1940 Clintonia †3,106 Damaged 5,154 Sunk 1,643 Sunk Thalia5,875 Sunk

Sixth patrol U-99 departed Lorient for the North West Approaches on 30 October 1940; four ships were sunk. The patrol ended on 8 November.

Date Ship Nationality TonnageMerchant ship tonnages are in gross register tons. Military vessels are listed by tons displacement. (GRT) Fate3 November 1940 Casanare5,376Sunk 18,724 Sunk 4 November 1940 HMS Patroclus11,314 Sunk 5 November 1940 Scottish Maiden †6,993 Sunk

† Convoy HX 83

Seventh patrol On 27 November, U-99 departed Lorient for the North Atlantic. Four ships were sunk. The patrol ended on 12 December.

Date Ship Nationality TonnageMerchant ship tonnages are in gross register tons. Military vessels are listed by tons displacement. (GRT) Fate2 December 1940 16,402 Sunk Samnanger4,276 Sunk 3 December 1940 Conch †8,376 Sunk 7 December 1940 Farmsum ‡5,237 Sunk

† Convoy HX 90, ‡ Convoy OB 252

Eighth patrol U-99 departed Lorient on 22 February 1941 to patrol in the North Atlantic; eight ships were sunk. U-99 was attacked herself, with severe damage inflicted. Kretschmer surrendered and scuttled the submarine with the loss of three lives.

Date Ship Nationality TonnageMerchant ship tonnages are in gross register tons. Military vessels are listed by tons displacement. (GRT) Fate7 March 1941 Athelbeach †6,568 Sunk Terje Viken20,638 Sunk16 March 1941 Beduin ‡8,136 Sunk Ferm ‡6,593 Sunk Franche-Comté ‡9,314 Damaged J. B. White7,375 Sunk Korshamn ‡6,673 Sunk Venetia †5,728 Sunk

† Convoy OB 293, ‡ Convoy HX 112

Fate On 17 March 1941, U-99 had just fired the last of her torpedoes and sunk Korshamn when the Watch Officer spotted a destroyer, southeast of Iceland in approximate position . He immediately ordered a dive, contrary to Kretschmer's standing orders, but once the boat was under it was quickly fixed on ASDIC and attacked by and . U-99 was driven deep by the attack but was nonetheless severely damaged. Kretschmer had no choice but to surface; immediately a barrage of fire greeted the boat. Kretschmer sent a message to Donald Macintyre, Walkers captain, "CAPTAIN TO CAPTAIN. I AM SUNKING [sic] PLEASE RESCUE MY CREW." He then ordered that the boat should be scuttled. Forty crew, including Kretschmer, were rescued to become POWs. Three crewmen – the engineering-officer and two ratings – lost their lives. The engineering officer re-entered the sinking U-boat and perished while opening the galley hatch, to hasten the boat's sinking and prevent the British from boarding it.

Macintyre took Kretschmer's binoculars as a souvenir. However in 1955, he gave them back to Kretschmer.

Wolfpack operations U-99 operated with the following Wolfpacks during her career: Wolfpack 1 (20 – 22 September 1940) Wolfpack 2 (17 – 19 October 1940)

Summary of raiding history DateNameNationalityTonnageMerchant ship tonnages are in gross register tons. Military vessels are listed by tons displacement.Fate5 July 1940Magog2,053Sunk7 July 1940Sea Glory1,964Sunk7 July 1940Bissen1,514Sunk8 July 1940Humber Arm5,758Sunk12 July 1940Ia4,860Sunk12 July 1940Merisaar2,136Captured as prize18 July 1940Woodbury4,434Sunk28 July 1940Auckland Star13,212Sunk29 July 1940Clan Menzies7,336Sunk31 July 1940Jamaica Progress5,475Sunk31 July 1940Jersey City6,322Sunk2 August 1940Strinda10,973Damaged2 August 1940Lucerna6,556Damaged2 August 1940Alexia8,016Damaged11 September 1940Albionic2,468Sunk15 September 1940Kenordoc1,780Sunk16 September 1940Lotos1,327Sunk17 September 19402,372Sunk21 September 1940Invershannon9,154Sunk21 September 1940Baron Blythswood3,668Sunk21 September 1940Elmbank5,156Sunk18 October 19406,055Sunk18 October 1940Niritos3,854Sunk18 October 19404,815Sunk19 October 19405,154Sunk19 October 1940Thalia5,875Sunk19 October 19401,643Sunk19 October 1940Clintonia3,106Damaged 3 November 1940 Casanare5,376Sunk3 November 1940 18,724Sunk4 November 1940 HMS Patroclus11,314Sunk5 November 1940 Scottish Maiden6,993Sunk2 December 194016,402Sunk2 December 1940Samnanger4,276Sunk3 December 1940Conch8,376Sunk7 December 1940Farmsum5,237Sunk7 March 1941Terje Viken20,638Sunk7 March 1941Athelbeach6,568Sunk16 March 1941Beduin8,136Sunk16 March 1941Franche-Comté9,314Damaged16 March 1941J. B. White7,375Sunk16 March 1941Korshamn6,673Sunk16 March 1941Venetia5,728Sunk16 March 1941Ferm6,593Sunk

See also List of successful U-boats Operation Kiebitz

References

Notes

Citations

Bibliography

External links

uboataces.com webpage with insignia for U-99 uboatarchive.net U-99 Interrogation of Survivors, Naval Intelligence Division, April 1941