German submarine U-409

German submarine U-409 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine in World War II. She was laid down on 26 October 1940 by Danziger Werft, Danzig as yard number 110, launched on 23 September 1941 and commissioned on 31 January 1942 under Oberleutnant zur See Hanns-Ferdinand Massmann.

Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-409 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 Siemens-Schuckert GU 343/38–8 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-409 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 an anti-aircraft gun. The boat had a complement of between forty-four and sixty.

Service history
The boat's career began with training at 5th U-boat Flotilla on 21 January 1942, followed by active service on 1 September 1942 as part of the 9th Flotilla. The following year, she transferred to 29th Flotilla for operations in the Mediterranean.

In six patrols she sank four merchant ships, for a total of, 1 merchant ship damaged , and one warship sunk whilst being transported.

Wolfpacks
U-409 took part in six wolfpacks, namely
 * Vorwärts (25 August – 2 September 1942)
 * Streitaxt (20 October – 1 November 1942)
 * Raufbold (11–18 December 1942)
 * Sturmbock (21–26 February 1943)
 * Wildfang (26 February – 5 March 1943)
 * Westmark (6–11 March 1943)

Fate
U-409 was sunk on 12 July 1943 in the Mediterranean NE of Algiers, in position 37.2°N, 4°W, by depth charges from the Royal Navy destroyer HMS Inconstant (H49).