German submarine U-739 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II.She was laid down on 17 April 1942 by Schichau-Werke, Danzig as yard number 1536, launched on 23 December 1942 and commissioned on 6 March 1943 under Leutnant zur See Ernst Mangold.
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-739 had a displacement of 769t when at the surface and 871t while submerged. She had a total length of 67.1m (220.1feet), a pressure hull length of 50.5m (165.7feet), a beam of 6.2m (20.3feet), a height of 9.6m (31.5feet), and a draught of 4.74m (15.55feet). The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of NaNPS for use while surfaced, two AEG GU 460/8–27 double-acting electric motors producing a total of 750PS for use while submerged. She had two shafts and two 1.23abbr=onNaNabbr=on propellers. The boat was capable of operating at depths of up to .
The submarine had a maximum surface speed of and a maximum submerged speed of . When submerged, the boat could operate for at ; when surfaced, she could travel at . U-739 was fitted with five 53.30NaN0 torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.82NaN2 SK C/35 naval gun, 220 rounds, and two twin 2sp=usNaNsp=us C/30 anti-aircraft guns. The boat had a complement of between forty-four and sixty.
The boat's career began with training at 8th U-boat Flotilla on 6 March 1943, followed by active service on 1 November 1943 as part of the 9th Flotilla. Just two months later she transferred to 13th Flotilla for the remainder of her service.
In eight patrols she sank one warship for a total of 625 tons.
U-739 took part in eight wolfpacks, namely:
U-739 surrendered on 13 May 1945 at Emden. Sunk later on 16 December 1945, in position 56.1667°N -15°W in Operation Deadlight.