German submarine U-503

U-505, a typical Type IXC boat
History
Nazi Germany
Name:	U-503
Ordered:	25 September 1939
Builder:	Deutsche Werft, Hamburg
Yard number:	293
Laid down:	29 April 1940
Launched:	5 April 1941
Commissioned:	10 July 1941
Fate:	Sunk, 15 March 1942
General characteristics
Class & type:	Type IXC submarine
Displacement:	1,120 t (1,100 long tons) surfaced 1,232 t (1,213 long tons) submerged
Length:	76.76 m (251 ft 10 in) o/a 58.75 m (192 ft 9 in) pressure hull
Beam:	6.76 m (22 ft 2 in) o/a 4.40 m (14 ft 5 in) pressure hull
Height:	9.60 m (31 ft 6 in)
Draught:	4.70 m (15 ft 5 in)
Installed power:	4,400 PS (3,200 kW; 4,300 bhp) (diesels) 1,000 PS (740 kW; 990 shp) (electric)
Propulsion:	2 shafts 2 × diesel engines 2 × electric motors
Speed:	18.2 knots (33.7 km/h; 20.9 mph) surfaced 7.7 knots (14.3 km/h; 8.9 mph) submerged
Range:	13,450 nmi (24,910 km; 15,480 mi) at 10 knots (19 km/h; 12 mph) surfaced 64 nmi (119 km; 74 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged
Test depth:	230 m (750 ft)
Complement:	4 officers, 44 enlisted
Armament:	6 × torpedo tubes (4 bow, 2 stern) 22 × 53.3 cm (21 in) torpedoes 1 × 10.5 cm (4.1 in)deck gun (180 rounds) 1 × 3.7 cm (1.5 in) AA gun 1 × twin 2 cm FlaK 30 AA guns
Service record
Part of:	2nd U-boat Flotilla 10 July 1941 – 15 March 1942
Commanders:	Kptlt. Otto Gericke 10 July 1941 – 15 March 1942
Operations:	1st patrol: 28 February – 15 March 1942
Victories:	None

German submarine U-503 was a Type IXC U-boat of Nazi Germany's Kriegsmarine during World War II. The submarine was laid down on 29 April 1940 at the Deutsche Werft yard in Hamburg as yard number 293, launched on 5 April 1941 and commissioned on 10 July 1941 under the command of Kapitänleutnant Otto Gericke.

The boat's service began with her being assigned to the 2nd U-boat Flotilla on her commissioning date for training and continuing with it for operations from 1 February 1942.

Design

German Type IXC submariness were slightly larger than the original Type IXBs. U-503 had a displacement of 1,120 tonnes (1,100 long tons) when at the surface and 1,232 tonnes (1,213 long tons) while submerged. The U-boat had a total length of 76.76 m (251 ft 10 in), a pressure hull length of 58.75 m (192 ft 9 in), a beam of 6.76 m (22 ft 2 in), a height of 9.60 m (31 ft 6 in), and a draught of 4.70 m (15 ft 5 in). The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of 4,400 metric horsepower (3,240 kW; 4,340 shp) for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of 1,000 shaft horsepower (1,010 PS; 750 kW) for use while submerged. She had two shafts and two 1.92 m (6 ft) propellers. The boat was capable of operating at depths of up to 230 metres (750 ft).

The submarine had a maximum surface speed of 18.3 knots (33.9 km/h; 21.1 mph) and a maximum submerged speed of 7.3 knots (13.5 km/h; 8.4 mph). When submerged, the boat could operate for 63 nautical miles (117 km; 72 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 13,450 nautical miles (24,910 km; 15,480 mi) at 10 knots (19 km/h; 12 mph). U-503 was fitted with six 53.3 cm (21 in) torpedo tubes (four fitted at the bow and two at the stern), 22 torpedoes, one 10.5 cm (4.13 in) SK C/32 naval gun, 180 rounds, and a 3.7 cm (1.5 in) as well as a 2 cm (0.79 in) anti-aircraft gun. The boat had a complement of forty-eight.

Service history

U-503's first and only active war patrol began at Bergen in Norway on 28 February 1942, following two previous port to port sailings. The U-boat was sunk on 15 March by depth charges dropped by a PBO-1 Hudson of United States Navy squadron VP-82 south-east of Newfoundland, in position .

The aircraft, from Argentia, was escorting Convoy ON-72. The PBO-1s were twenty Hudson Mk.IIIA aircraft diverted from Lend-Lease to equip VP-82, and sank the first two U-boats by US forces; U-656 on 1 March 1942 and U-503.