German submarine U-309

History
Nazi Germany
NameU-309
Ordered5 June 1941
BuilderFlender Werke, Lübeck
Yard number309
Laid down24 January 1942
Launched5 December 1942
Commissioned27 January 1943
FateSunk on 16 February 1945
General characteristics
Class & typeType VIIC submarine
Displacement
Length
Beam
  • 6.20 m (20 ft 4 in) o/a
  • 4.70 m (15 ft 5 in) pressure hull
Height9.60 m (31 ft 6 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
  • 17.7 knots (32.8 km/h; 20.4 mph) surfaced
  • 7.6 knots (14.1 km/h; 8.7 mph) submerged
Range
  • 8,500 nmi (15,700 km; 9,800 mi) at 10 knots (19 km/h; 12 mph) surfaced
  • 80 nmi (150 km; 92 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged
Test depth
  • 230 m (750 ft)
  • Crush depth: 250–295 m (820–968 ft)
Complement4 officers, 40–56 enlisted
Armament
Service record
Part of:
Identification codes: M 49 703
Commanders:
  • Oblt.z.S. Hans-Gert Mahrholz
  • 27 January 1943 – August 1944
  • Oblt.z.S.. Herbert Loeder
  • August 1944 – 16 February 1945
Operations:
  • 9 patrols:
  • 1st patrol:
  • a. 13 – 18 September 1943
  • b. 25 September – 7 November 1943
  • 2nd patrol:
  • a. 19 December 1943 – 14 February 1944
  • b. 8 – 10 April 1944
  • 3rd patrol:
  • 20 – 25 June 1944
  • 4th patrol:
  • 28 June – 6 July 1944
  • 5th patrol:
  • a. 12 July – 3 August 1944
  • b. 7 – 12 August 1944
  • 6th patrol:
  • 29 August – 13 October 1944
  • 7th patrol:
  • 15 – 21 October 1944
  • 8th patrol:
  • 30 January – 2 February 1945
  • 9th patrol:
  • 8 – 16 February 1945
Victories: 1 merchant ship total loss
(7,219 GRT)

German submarine U-309 was a Type VIIC U-boat of the German Navy (Kriegsmarine) during World War II. The submarine was laid down on 24 January 1942 at the Flender Werke yard at Lübeck, launched on 5 December 1942, and commissioned on 27 January 1943 under the command of Oberleutnant zur See Hans-Gert Mahrholz. She sailed on nine combat patrols, but damaged only one ship, before being sunk off Scotland on 16 February 1945.