Construction

U-36 was ordered by the Kriegsmarine on 25 March 1935 as part of the German Plan Z and in violation of the Treaty of Versailles. Her keel was laid down in the AG Weser shipyard in Bremen as yard number 559 on 2 March 1936. After about eight months of construction, she was launched on 4 November 1936 and commissioned on 16 December under the command of Kptlt. Klaus Ewerth.^[1]

Design

Like all Type VIIA submarines, U-36 displaced 626 tonnes (616 long tons) while surfaced and 745 t (733 long tons) when submerged. She was 64.51 m (211 ft 8 in) in overall length and had a 45.50 m (149 ft 3 in) pressure hull. U-36's propulsion consisted of two MAN 6-cylinder 4-stroke M6V 40/46 diesel engines that totaled 2,100–2,310 PS (1,540–1,700 kW; 2,070–2,280 bhp). Her maximum rpm was between 470 and 485. The submarine was also equipped with two Brown, Boveri & Cie GG UB 720/8 electric motors that totaled 750 PS (550 kW; 740 shp). Their maximum rpm was 322. These engines gave U-36 a total speed of 17 knots (31 km/h; 20 mph) while surfaced and 8 knots (15 km/h; 9.2 mph) when submerged. This resulted in a range of 6,200 nmi (11,500 km; 7,100 mi) while traveling at 10 knots (19 km/h; 12 mph) on the surface and 73–94 nmi (135–174 km; 84–108 mi) at 4 knots (7.4 km/h; 4.6 mph) when submerged. The U-boat's test depth was 220 m (720 ft) but she could go as deep as 230–250 m (750–820 ft) without having her hull crushed.^[3]

U-36's armament consisted of five 53.3 cm (21 in) torpedo tubes (four located in the bow and one in the stern). She could have up to 11 torpedoes on board or 22 TMA or 33 TMB mines. U-36 was also equipped with a 8.8 cm SK C/35 naval gun and had 220 rounds for it stowed on board. Her anti-aircraft defenses consisted of one 2 cm (0.79 in) anti-aircraft gun.^[3]

First war patrol

U-36 was at sea when the war broke out, having set out from Wilhelmshaven on 31 August 1939. She arrived in Kiel on 6 September and the following day departed for her first war patrol.^[4] She then patrolled the North Sea for three weeks, hoping to catch ships traveling between Britain and Scandinavia carrying war supplies. During this patrol, the boat sank two steamers, Truro and Silesia—one British and the other from neutral Sweden—carrying British produce.

Seahorse, a British submarine, later fired on U-36 and subsequently claimed to have sunk her, although in fact the torpedo missed.^[5] On 27 September Fröhlich and his crew captured another Swedish vessel, Algeria, which he proceeded to escort back to Germany as the patrol came to an end.^[4][5] She returned to her berth in Kiel at the end of September, where she remained until December.^[6]

Second war patrol

On 17 November 1939, Naval High Command (SKL) issued orders for U-36 and U-38 to scout the location for Basis Nord, a secret German naval base for raids on Allied shipping located off the Kola Peninsula and provided by the Soviet Union.^[7] The mission required coded messages to be flashed to Soviet naval vessels patrolling the area preceding a Soviet escort to the prospective base location.^[8]

However, U-36 never left the Norwegian Sea.^[8] On 4 December 1939, two days out of Wilhelmshaven, she was spotted on the surface near the Norwegian port of Stavanger by the British submarine Salmon. Salmon then fired one torpedo at her unwitting counterpart. It sank U-36, all 40 of the sailors aboard were lost.^[8][9] During the same patrol, the Salmon also torpedoed the light cruisers Leipzig and Nürnberg.^[10]

Following the loss of U-36, U-38 continued towards the Kola Peninsula, successfully reaching the location and accomplished the scouting mission for Basis Nord.^[8]