German submarine U-99 (1940)

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.

For other ships with the same name, see German submarine U-99.
U-52, a typical Type VIIB boat
History
Nazi Germany
NameU-99
Ordered15 December 1937
BuilderGermaniawerft, Kiel
Yard number593
Laid down31 March 1939
Launched12 March 1940
Commissioned18 April 1940
FateSunk on 17 March 1941, by HMS Walker southeast of Iceland. Three dead and 40 survivors[1][2]
General characteristics
Class and typeType VIIB submarine
Displacement
  • 753 tonnes (741 long tons) surfaced
  • 857 t (843 long tons) submerged
Length
Beam
  • 6.20 m (20 ft 4 in) o/a
  • 4.70 m (15 ft 5 in) pressure hull
Height9.50 m (31 ft 2 in)
Draught4.74 m (15 ft 7 in)
Installed power
  • 2,800–3,200 PS (2,100–2,400 kW; 2,800–3,200 bhp) (diesels)
  • 750 PS (550 kW; 740 shp) (electric)
Propulsion
Speed
  • 17.9 knots (33.2 km/h; 20.6 mph) surfaced
  • 8 knots (15 km/h; 9.2 mph) submerged
Range
  • 9,400 nmi (17,400 km; 10,800 mi) at 10 knots (19 km/h; 12 mph) surfaced
  • 90 nmi (170 km; 100 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged
Test depth
  • 220 m (720 ft)
  • Crush depth: 230–250 m (750–820 ft)
Complement4 officers, 40–56 enlisted
Sensors and
processing systems		Gruppenhorchgerät
Armament
Service record
Part of:
Identification codes: M 17 046
Commanders:
Operations:
  • 8 patrols:
  • 1st patrol:
  • 18–25 June 1940
  • 2nd patrol:
  • 27 June – 21 July 1940
  • 3rd patrol:
  • 25 July – 5 August 1940
  • 4th patrol:
  • 4 – 25 September 1940
  • 5th patrol:
  • 13 – 22 October 1940
  • 6th patrol:
  • 30 October – 8 November 1940
  • 7th patrol:
  • 27 November – 12 December 1940
  • 8th patrol:
  • 22 February – 17 March 1941
Victories:
  • 35 merchant ships sunk
    (198,218 GRT)
  • 3 auxiliary warships sunk
    (46,440 GRT)
  • 5 merchant ships damaged
    (37,965 GRT)
  • 1 merchant ship taken as prize
    (2,136 GRT)

U-99 was one of the most successful German U-boats in the war, sinking 38 ships for a total tonnage of 244,658 gross register tons (GRT) 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 753 tonnes (741 long tons) when at the surface and 857 tonnes (843 long tons) while submerged.[3] She had a total length of 66.50 m (218 ft 2 in), a pressure hull length of 48.80 m (160 ft 1 in), a beam of 6.20 m (20 ft 4 in), a height of 9.50 m (31 ft 2 in), and a draught of 4.74 m (15 ft 7 in). The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2,800 to 3,200 metric horsepower (2,060 to 2,350 kW; 2,760 to 3,160 shp) for use while surfaced, two BBC GG UB 720/8 double-acting electric motors producing a total of 750 metric horsepower (550 kW; 740 shp) for use while submerged. She had two shafts and two 1.23 m (4 ft) propellers. The boat was capable of operating at depths of up to 230 metres (750 ft).[3]

The submarine had a maximum surface speed of 17.9 knots (33.2 km/h; 20.6 mph) and a maximum submerged speed of 8 knots (15 km/h; 9.2 mph).[3] When submerged, the boat could operate for 90 nautical miles (170 km; 100 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 8,700 nautical miles (16,100 km; 10,000 mi) at 10 knots (19 km/h; 12 mph). U-99 was fitted with five 53.3 cm (21 in) torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm (3.46 in) SK C/35 naval gun, 220 rounds, and one 2 cm (0.79 in) anti-aircraft gun The boat had a complement of between forty-four and sixty.[3]

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 Scharnhorst attacked her, having mistaken her for a British submarine. Two days later, U-99 was attacked by two aircraft; minor damage was inflicted.[4] 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.[4] On this patrol U-99 sank six ships and captured one, the Estonian 2,136 GRT cargo steamship Merisaar, carrying a load of timber from New Orleans, to Cork, Ireland.)[5] An attack on the 5,360 GRT Manistee was called off on 7 July, when the defensively equipped merchant ship returned fire.[6] On 8 July, over 100 depth charges were dropped by the escorts of Convoy HX 53, but U-99 escaped undamaged.[4] The patrol ended on 21 July.

Painting of Merisaar's lifeboat approaching U-99 on 12 July 1940
Date Ship Nationality Tonnage[Note 1] Fate
5 July 1940 Magog †  Canada 2,053 Sunk
7 July 1940 Bissen  Sweden 1,514 Sunk
Manistee  United Kingdom 5,360 Escaped
Sea Glory  United Kingdom 1,964 Sunk
8 July 1940 Humber Arm ‡  United Kingdom 5,758 Sunk
12 July 1940 Ia  Greece 4,860 Sunk
Merisaar*  Estonia 2,136 Captured as prize
18 July 1940 Woodbury  United Kingdom 4,434 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.[4] The patrol ended on 5 August.

Date Ship Nationality Tonnage[Note 1] (GRT) Fate
28 July 1940 Auckland Star  United Kingdom 13,212 Sunk
29 July 1940 Clan Menzies  United Kingdom 7,336 Sunk
31 July 1940 Jamaica Progress  United Kingdom 5,475 Sunk
Jersey City †  United Kingdom 6,322 Sunk
2 August 1940 Alexia †, ‡  United Kingdom 8,016 Damaged
Lucerna †, ‡  United Kingdom 6,556 Damaged
Strinda †, ‡  Norway 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.[4]

Date Ship Nationality Tonnage[Note 1] (GRT) Fate
11 September 1940 Albionic  United Kingdom 2,468 Sunk
15 September 1940 Kenordoc †  Canada 1,780 Sunk
16 September 1940 Lotos †  Norway 1,327 Sunk
17 September 1940 Crown Arun ‡  United Kingdom 2,372 Sunk
21 September 1940 Baron Blythswood *  United Kingdom 3,668 Sunk
Elmbank *  United Kingdom 5,156 Sunk
Invershannon*  United Kingdom 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.

Empire Brigade
Postcard of Laurentic
Date Ship Nationality Tonnage[Note 1] (GRT) Fate
18 October 1940 Empire Miniver  United Kingdom 6,055 Sunk
Fiscus  United Kingdom 4,815 Sunk
Niritos  Greece 3,854 Sunk
19 October 1940 Clintonia †  United Kingdom 3,106 Damaged
Empire Brigade  United Kingdom 5,154 Sunk
Snefjeld  Norway 1,643 Sunk
Thalia  Greece 5,875 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 Tonnage[Note 1] (GRT) Fate
3 November 1940 Casanare  United Kingdom 5,376 Sunk
HMS Laurentic  Royal Navy 18,724 Sunk
4 November 1940 HMS Patroclus  Royal Navy 11,314 Sunk
5 November 1940 Scottish Maiden †  United Kingdom 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 Tonnage[Note 1] (GRT) Fate
2 December 1940 HMS Forfar  Royal Navy 16,402 Sunk
Samnanger  Norway 4,276 Sunk
3 December 1940 Conch †  United Kingdom 8,376 Sunk
7 December 1940 Farmsum ‡  Netherlands 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 Tonnage[Note 1] (GRT) Fate
7 March 1941 Athelbeach †  United Kingdom 6,568 Sunk
Terje Viken  United Kingdom 20,638 Sunk
16 March 1941 Beduin ‡  Norway 8,136 Sunk
Ferm ‡  Norway 6,593 Sunk
Franche-Comté ‡  United Kingdom 9,314 Damaged
J. B. White  Canada 7,375 Sunk
Korshamn ‡  Sweden 6,673 Sunk
Venetia †  United Kingdom 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 61°N 12°W. He immediately ordered a dive, contrary to Kretschmer's standing orders,[7] but once the boat was under it was quickly fixed on ASDIC and attacked by HMS Walker and Vanoc. 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, Walker's captain, "CAPTAIN TO CAPTAIN. I AM SUNKING [sic] PLEASE RESCUE MY CREW."[8] 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.[9] 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.[10]

Macintyre took Kretschmer's binoculars as a souvenir. But 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
Date Name Nationality Tonnage[Note 1] Fate[11]
5 July 1940 Magog  Canada 2,053 Sunk
7 July 1940 Sea Glory  United Kingdom 1,964 Sunk
7 July 1940 Bissen  Sweden 1,514 Sunk
8 July 1940 Humber Arm  United Kingdom 5,758 Sunk
12 July 1940 Ia  Greece 4,860 Sunk
12 July 1940 Merisaar  Estonia 2,136 Captured as prize
18 July 1940 Woodbury  United Kingdom 4,434 Sunk
28 July 1940 Auckland Star  United Kingdom 13,212 Sunk
29 July 1940 Clan Menzies  United Kingdom 7,336 Sunk
31 July 1940 Jamaica Progress  United Kingdom 5,475 Sunk
31 July 1940 Jersey City  United Kingdom 6,322 Sunk
2 August 1940 Strinda  Norway 10,973 Damaged
2 August 1940 Lucerna  United Kingdom 6,556 Damaged
2 August 1940 Alexia  United Kingdom 8,016 Damaged
11 September 1940 Albionic  United Kingdom 2,468 Sunk
15 September 1940 Kenordoc  Canada 1,780 Sunk
16 September 1940 Lotos  Norway 1,327 Sunk
17 September 1940 Crown Arun  United Kingdom 2,372 Sunk
21 September 1940 Invershannon  United Kingdom 9,154 Sunk
21 September 1940 Baron Blythswood  United Kingdom 3,668 Sunk
21 September 1940 Elmbank  United Kingdom 5,156 Sunk
18 October 1940 Empire Miniver  United Kingdom 6,055 Sunk
18 October 1940 Niritos  Greece 3,854 Sunk
18 October 1940 Fiscus  United Kingdom 4,815 Sunk
19 October 1940 Empire Brigade  United Kingdom 5,154 Sunk
19 October 1940 Thalia  Greece 5,875 Sunk
19 October 1940 Snefjeld  Norway 1,643 Sunk
19 October 1940 Clintonia  United Kingdom 3,106 Damaged
3 November 1940 Casanare  United Kingdom 5,376 Sunk
3 November 1940 HMS Laurentic  Royal Navy 18,724 Sunk
4 November 1940 HMS Patroclus  Royal Navy 11,314 Sunk
5 November 1940 Scottish Maiden  United Kingdom 6,993 Sunk
2 December 1940 HMS Forfar  Royal Navy 16,402 Sunk
2 December 1940 Samnanger  Norway 4,276 Sunk
3 December 1940 Conch  United Kingdom 8,376 Sunk
7 December 1940 Farmsum  Netherlands 5,237 Sunk
7 March 1941 Terje Viken  United Kingdom 20,638 Sunk
7 March 1941 Athelbeach  United Kingdom 6,568 Sunk
16 March 1941 Beduin  Norway 8,136 Sunk
16 March 1941 Franche-Comté  United Kingdom 9,314 Damaged
16 March 1941 J. B. White  Canada 7,375 Sunk
16 March 1941 Korshamn  Sweden 6,673 Sunk
16 March 1941 Venetia  United Kingdom 5,728 Sunk
16 March 1941 Ferm  Norway 6,593 Sunk

See also

References

Notes
  1. Merchant ship tonnages are in gross register tons. Military vessels are listed by tons displacement.

Citations
  1. Kemp 1997, p. 69.
  2. Niestle 1998, p. 41.
  3. Gröner 1991, pp. 43–44.
  4. Helgason, Guðmundur. "U-99". uboat.net. Retrieved 17 November 2009.
  5. Helgason, Guðmundur. "Merisaar". uboat.net. Retrieved 17 November 2009.
  6. Helgason, Guðmundur. "HMS Manistee (F104)". uboat.net. Retrieved 17 November 2009.
  7. White 2006, p. 79.
  8. White 2006, p. 81.
  9. C.B. 04051 (20) "U 99" Interrogation of Survivors. Naval Intelligence Division, Admiralty. April 1941. p. 7.
  10. C.B. 04051 (20) "U 99" Interrogation of Survivors. Naval Intelligence Division, Admiralty. April 1941. p. 14.
  11. Helgason, Guðmundur. "Ships hit by U-99". German U-boats of WWII - uboat.net. Retrieved 11 December 2013.

Bibliography
  • Busch, Rainer; Röll, Hans-Joachim (1999). German U-boat commanders of World War II : a biographical dictionary. Translated by Brooks, Geoffrey. London, Annapolis, Md: Greenhill Books, Naval Institute Press. ISBN 1-55750-186-6.
  • Busch, Rainer; Röll, Hans-Joachim (1999). Deutsche U-Boot-Verluste von September 1939 bis Mai 1945 [German U-boat losses from September 1939 to May 1945]. Der U-Boot-Krieg (in German). Vol. IV. Hamburg, Berlin, Bonn: Mittler. ISBN 3-8132-0514-2.
  • Edwards, Bernard (1996). Dönitz and the Wolf Packs – The U-boats at War. Cassell Military Classics. pp. 23, 27, 28, 32, 35, 42–44, 48–49. ISBN 0-304-35203-9.
  • Gröner, Erich; Jung, Dieter; Maass, Martin (1991). German Warships 1815–1945, U-boats and Mine Warfare Vessels. Vol. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.
  • Kemp, Paul (1997). U-Boats Destroyed, German Submarine Losses in the World Wars. Arms and Armour. ISBN 1-85409-515-3.
  • Niestle, Axel (1998). German U-Boat Losses during World War II. Greenhill Books. ISBN 1-85367-352-8.
  • Sharpe, Peter (1998). U-Boat Fact File. Great Britain: Midland Publishing. ISBN 1-85780-072-9.
  • White, David Fairbank (2006). Bitter Ocean – The dramatic story of the Battle of the Atlantic 1939–1945. Headline Publishing Group. ISBN 978-0-7553-1089-0.

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