German submarine U-23 (1936)

For other ships with the same name, see German submarine U-23.

U-9, a typical Type IIB boat
History
Nazi Germany
Name	U-23
Ordered	2 February 1935
Builder	Germaniawerft, Kiel Galați shipyard, Romania
Yard number	553
Laid down	11 April 1936
Launched	28 August 1936
Commissioned	24 September 1936
Fate	Scuttled 11 September 1944, off the coast of Turkey in the Black Sea
General characteristics
Class & type	Type IIB coastal submarine
Displacement	279  t (275 long tons) surfaced 328 t (323 long tons) submerged
Length	42.70 m (140 ft 1 in) o/a 27.80 m (91 ft 2 in) pressure hull
Beam	4.08 m (13 ft 5 in) (o/a) 4.00 m (13 ft 1 in) (pressure hull)
Height	8.60 m (28 ft 3 in)
Draught	3.90 m (12 ft 10 in)
Installed power	700 PS (510 kW; 690 bhp) (diesels) 410 PS (300 kW; 400 shp) (electric)
Propulsion	2 shafts 2 × diesel engines 2 × electric motors
Speed	13 knots (24 km/h; 15 mph) surfaced 7 knots (13 km/h; 8.1 mph) submerged
Range	1,800 nmi (3,300 km; 2,100 mi) at 12 knots (22 km/h; 14 mph) surfaced 35–43 nmi (65–80 km; 40–49 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged
Test depth	80 m (260 ft)
Complement	3 officers, 22 men
Armament	3 × 53.3 cm (21 in) torpedo tubes 5 × torpedoes or up to 12 TMA or 18 TMB mines 1 × 2 cm (0.79 in) anti-aircraft gun
Service record
Part of:	1st U-boat Flotilla 1 September 1936 – 1 August 1939 1 September 1939 – 30 June 1940 21st U-boat Flotilla 1 July 1940 – 26 Aug 1942 30th U-boat Flotilla 3 June 1943 – 10 September 1944
Identification codes:	M 01 984
Commanders:	Kptlt. / K.Kapt. Eberhard Godt 1 September 1936 – 3 January 1938 Kptlt. Hans-Günther Looff 1936 / 37 – 30 September 1937 Oblt.z.S. / Kptlt. Otto Kretschmer 1 October 1937 – 1 April 1940 Kptlt. Heinz Beduhn 8 April – 19 May 1940 Oblt.z.S. Heinrich Driver 20 May – 30 September 1940 Oblt.z.S. Kurt Reichenbach-Klinke 1 October 1940 – 20 March 1941 Oblt.z.S. Ernst-Ulrich Brüller 21 March – 23 September 1941 Oblt.z.S. Ulrich Gräf 24 September 1941 – 26 March 1942 Oblt.z.S. / Kptlt. Rolf-Birger Wahlen 27 March – 26 August 1942 3 June 1943 – 19 June 1944 Oblt.z.S. Rudolf Arendt 20 June – 10 September 1944
Operations:	16 patrols: 1st patrol: 25 August – 4 September 1939 2nd patrol: a. 9 – 21 September 1939 b. 29 – 30 September 1939 3rd patrol: 1 – 16 October 1939 4th patrol: 1 – 9 November 1939 5th patrol: 5 – 15 December 1939 6th patrol: 8 – 15 January 1940 7th patrol: 18 – 29 January 1940 8th patrol: a. 9 – 25 February 1940 b. 26 – 28 February 1940 c. 9 – 10 April 1940 9th patrol: 13 April – 3 May 1940 10th patrol: a. 27 June – 16 July 1943 b. 18 – 19 July 1943 11th patrol: 10 August – 9 September 1943 12th patrol: 10 October – 11 November 1943 13th patrol: 14 December 1943 – 7 January 1944 14th patrol: 30 March – 24 April 1944 15th patrol: 17 May – 7 June 1944 16th patrol: 16 August – 10 September 1944
Victories:	7 merchant ships sunk (11,179  GRT) 2 warships sunk (1,410 tons) 3 merchant ships total loss (18,199  GRT) 1 warship damaged (56 tons) 1 auxiliary warship damaged (1,005  GRT)

German submarine U-23 was a Type IIB U-boat of Nazi Germany's Kriegsmarine , built in Germaniawerft, Kiel. She was laid down on 11 April 1936 and commissioned on 24 September.

Design

German Type IIB submarines were enlarged versions of the original Type IIs. U-23 had a displacement of 279 tonnes (275 long tons) when at the surface and 328 tonnes (323 long tons) while submerged. Officially, the standard tonnage was 250 long tons (254 t), however. ^[1] The U-boat had a total length of 42.70 m (140 ft 1 in), a pressure hull length of 28.20 m (92 ft 6 in), a beam of 4.08 m (13 ft 5 in), a height of 8.60 m (28 ft 3 in), and a draught of 3.90 m (12 ft 10 in). The submarine was powered by two MWM RS 127 S four-stroke, six-cylinder diesel engines of 700 metric horsepower (510 kW; 690 shp) for cruising, two Siemens-Schuckert PG VV 322/36 double-acting electric motors producing a total of 460 metric horsepower (340 kW; 450 shp) for use while submerged. She had two shafts and two 0.85 m (3 ft) propellers. The boat was capable of operating at depths of up to 80–150 metres (260–490 ft). ^[1]

The submarine had a maximum surface speed of 12 knots (22 km/h; 14 mph) and a maximum submerged speed of 7 knots (13 km/h; 8.1 mph). ^[1] When submerged, the boat could operate for 35–42 nautical miles (65–78 km; 40–48 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 3,800 nautical miles (7,000 km; 4,400 mi) at 8 knots (15 km/h; 9.2 mph). U-23 was fitted with three 53.3 cm (21 in) torpedo tubes at the bow, five torpedoes or up to twelve Type A torpedo mines, and a 2 cm (0.79 in) anti-aircraft gun. The boat had a complement of twentyfive. ^[1]

Service history

At 04:45 on 4 October 1939, U-23 scored one of the Kriegsmarine's early successes of the war when she torpedoed and sank with gunfire, the merchant ship Glen Farg about 60 nmi (110 km; 69 mi) south-southwest of Sumburgh Head (southern Shetland). One person died, while 16 survivors were picked up by HMS Firedrake and landed at Kirkwall the next day.

In 16 patrols U-23 sank seven ships for a total of 11,179  gross register tons  (GRT) including two warships, as well as damaging a warship and an auxiliary warship.

Over the course of her service with the Kriegsmarine, U-23 had ten commanding officers, the most famous of whom was Kapitänleutnant Otto Kretschmer, who went on to become the top scoring U-boat ace. After service in the Atlantic with the 1st U-boat Flotilla, U-23 served as a training boat with the 21st U-boat Flotilla from July 1940 until September 1942. U-23 was then transported in sections along the Danube to the Romanian port of Galați. She was then re-assembled by the Romanians at the Galați shipyard and sent to the Black Sea port of Constanţa, Romania, with the 30th U-boat Flotilla until September 1944. ^[2]

Fate

U-23 was scuttled by her crew on 10 September 1944, off the coast of Turkey in the Black Sea at position 41°11′N30°00′E / 41.183°N 30.000°E / 41.183; 30.000 to prevent her capture by the advancing Soviets.^{[ citation needed ]}

On 3 February 2008, The Daily Telegraph newspaper reported that U-23 had been discovered by Selçuk Kolay, a Turkish marine engineer, in 160 ft (49 m) of water, three miles from the town of Ağva. ^{[3] [4]}

Summary of raiding history

Date	Name	Nationality	Tonnage [Note 1]	Fate [5]
4 October 1939	Glen Farg	United Kingdom	876	Sunk
8 December 1939	Scotia	Denmark	2,400	Sunk
11 January 1940	Fredville	Norway	1,150	Sunk
12 January 1940	Danmark	Denmark	10,517	Total loss
23 January 1940	Varild	Norway	1,085	Sunk
18 February 1940	HMS Daring	Royal Navy	1,375	Sunk
19 February 1940	Tiberton	United Kingdom	5,225	Sunk
22 February 1940	Loch Maddy	United Kingdom	4,996	Total loss
24 August 1943	Shkval	Soviet Navy	35	Sunk
15 October 1943	TSC-486 Sovetskja Rossiya	Soviet Navy	1,005	Damaged
23 October 1943	Tanais	Soviet Union	372	Sunk
5 April 1944	SKA-099	Soviet Navy	56	Damaged
29 May 1944	Smelyj	Soviet Union	71	Sunk
1 September 1944	Oituz	Romania	2,686	Sunk

References

Notes

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

Citations

1. Gröner 1991, pp. 39–40.
2. Steel and Ice: The U-boat Battle in the Arctic and Black Sea 1941-45, Chapter 5 - The Black Sea: War in the South 1942-43, page 5
3. Jasper Copping (3 February 2008). "Adolf Hitler's 'lost fleet' found in Black Sea". The Daily Telegraph . Retrieved 15 July 2010.
4. Andy McSmith (11 February 2008). "Hitler's 'lost fleet' of U-boats found in Black Sea". The Independent . London. Retrieved 15 July 2010.
5. Helgason, Guðmundur. "Ships hit by U-23". German U-boats of WWII - uboat.net. Retrieved 29 December 2014.

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.
• Gröner, Erich; Jung, Dieter; Maass, Martin (1991). U-boats and Mine Warfare Vessels. German Warships 1815–1945. Vol. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN   0-85177-593-4.

External links

• Helgason, Guðmundur. "The Type IIB boat U-23". German U-boats of WWII - uboat.net. Retrieved 6 December 2014.
• Hofmann, Markus. "U 23". Deutsche U-Boote 1935-1945 - u-boot-archiv.de (in German). Retrieved 6 December 2014.