German submarine U-434

German submarine U-434 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II.

The U-boat was laid down on 20 January 1940 at the Schichau-Werke yard, Danzig, launched on 15 March 1941, and commissioned on 21 June 1941, Kapitänleutnant Wolfgang Heyda commanding.

U-434 sailed from Kristiansand, Norway on 2 November 1941, on her only war patrol. On 18 December, U-434 was sunk in the North Atlantic north of Madeira, Portugal, in position 36.25°N, -15.8°W. The U-boat was forced to the surface by depth charges from the British escort destroyer HMS Blankney (L30) and the destroyer HMS Stanley (I73). There were two dead and 42 survivors.

Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-434 had a displacement of 769 t when at the surface and 871 t while submerged. She had a total length of 67.10 m, a pressure hull length of 50.50 m, a beam of 6.20 m, a height of 9.60 m, and a draught of 4.74 m. The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2800 to 3200 PS for use while surfaced, two AEG GU 460/8-276 double-acting electric motors producing a total of 750 PS for use while submerged. She had two shafts and two 1.23 m propellers. The boat was capable of operating at depths of up to 230 m.

The submarine had a maximum surface speed of 17.7 kn and a maximum submerged speed of 7.6 kn. When submerged, the boat could operate for 80 nmi at 4 kn; when surfaced, she could travel 8500 nmi at 10 kn. U-434 was fitted with five 53.3 cm torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm SK C/35 naval gun, 220 rounds, and a 2 cm C/30 anti-aircraft gun. The boat had a complement of between forty-four and sixty.

Wolfpacks
U-434 took part in two wolfpacks, namely:
 * Steuben (14 November – 1 December 1941)
 * Seeräuber (15 – 18 December 1941)