German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-436 had a displacement of 769 tonnes (757 long tons) when at the surface and 871 tonnes (857 long tons) while submerged.[3] She had a total length of 67.10 m (220 ft 2 in), a pressure hull length of 50.50 m (165 ft 8 in), a beam of 6.20 m (20 ft 4 in), a height of 9.60 m (31 ft 6 in), and a draught of 4.74 m (15 ft 7 in). The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder superchargeddiesel 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 AEG GU 460/8–27 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 17.7 knots (32.8 km/h; 20.4 mph) and a maximum submerged speed of 7.6 knots (14.1 km/h; 8.7 mph).[3] When submerged, the boat could operate for 80 nautical miles (150 km; 92 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 8,500 nautical miles (15,700 km; 9,800 mi) at 10 knots (19 km/h; 12 mph). U-436 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 a 2 cm (0.79 in) C/30 anti-aircraft gun. The boat had a complement of between forty-four and sixty.[3]
She served with the 5th U-boat Flotilla from 27 September 1941 for training and the 7th flotilla from 1 February 1942 for operations. She was reassigned, first to the 11th flotilla on 1 July, then the 6th flotilla on 1 September.
U-436's first patrol was from Kiel in Germany and took in the Norwegian and Barents Seas. She docked at Kirkenes, not far from the border between Norway and the Soviet Union on 17 February 1942.
The boat's initial success came when she sank the Soviet trawler RT-19 Komitern on 1 March 1942 east of Murmansk.
The submarine's third sortie commenced with her departure from Kirkenes on 7 April 1942. On the 13th, she sank the Soviet Kiev north of the North Cape. The vessel went down in seven minutes.
U-436 carried out her fourth and fifth patrols from Kirkenes and Trondheim. They were followed by a series of journeys which were not recognized as patrols. At their end, she was back in Kiel.
The U-boat left Kiel once more on 6 October 1942, but this time she was headed for the Atlantic Ocean, via the gap separating the Faroe and Shetland Islands.
On the 27th, she torpedoed, but did not sink, the Norwegian Frontenac in mid-Atlantic. The ship's bow section was badly damaged, so much so that her propeller was raised out of the water. The accompanying fire was extinguished by a large wave; the ship was pumped out and she was capable of moving under her own power. During the same attack, she sank the Sourabaya. Also lost was the landing craft HMS LCT-2281 which had been carried on deck. Two days later, the boat sank the Barrwhinn.
She arrived at Lorient in occupied France on 12 November.
Patrol number seven saw U-436 sink the Albert L. Ellsworth south of the Azores on 8 January 1943. The ship had been abandoned after being hit by a torpedo but remained afloat. The wreck was sunk by gunfire from the U-boat the following evening.
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. ISBN1-55750-186-6.
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. ISBN3-8132-0514-2.
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. ISBN0-85177-593-4.
Kemp, Paul (1999). U-Boats Destroyed – German Submarine Losses in the World Wars. London: Arms & Armour. ISBN1-85409-515-3.