German submarine U-804

German submarine U-804 was a Type IXC/40 U-boat of Nazi Germany's Kriegsmarine during World War II. U-804 was ordered on 7 December 1940, and was laid down on 1 December 1942 at Deutsche Schiff- und Maschinenbau AG Seebeckwerft, Bremerhaven as yard number 362. She was launched on 1 April 1943 and commissioned under the command of Oberleutnant zur See der Reserve Herbert Meyer (Crew III/37) on 4 December of that year.

Design
German Type IXC/40 submarines were slightly larger than the original Type IXCs. U-804 had a displacement of 1144 t when at the surface and 1257 t while submerged. The U-boat had a total length of 76.76 m, a pressure hull length of 58.75 m, a beam of 6.86 m, a height of 9.60 m, and a draught of 4.67 m. The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of 4400 PS for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of 1000 shp for use while submerged. She had two shafts and two 1.92 m propellers. The boat was capable of operating at depths of up to 230 m.

The submarine had a maximum surface speed of 18.3 kn and a maximum submerged speed of 7.3 kn. When submerged, the boat could operate for 63 nmi at 4 kn; when surfaced, she could travel 13850 nmi at 10 kn. U-804 was fitted with six 53.3 cm torpedo tubes (four fitted at the bow and two at the stern), 22 torpedoes, one 10.5 cm SK C/32 naval gun, 180 rounds, and a 3.7 cm Flak M42 as well as two twin 2 cm C/30 anti-aircraft guns. The boat had a complement of forty-eight.

Training
U-804 began training exercises with the 4th U-boat Flotilla on 4 December 1943, and finished her sea trials on 30 June 1944. On 16 June 1944, U-804 was attacked by a Norwegian Mosquito aircraft from No. 333 Squadron RAF, but succeeded in shooting down its attacker at the cost of eight crew members wounded; only minor damage was inflicted on the submarine. The two-man crew of the Mosquito was picked up by GS U-1000 on 18 June, and taken to occupied Norway.

First patrol
U-804 began her first war patrol on 19 June 1944 (while still undergoing training) with the 10th U-boat Flotilla. She left Bergen and headed into the North Sea, passing north of the British Isles into the North Atlantic, where she remained for 116 days. On 2 August, during a special hunt for several submarines known to be transmitting weather information from stations in the central and north Atlantic (of which effort U-804 was a part), two American destroyer escorts, USS Fiske (DE-143) and USS Douglas L. Howard (DE-138), were detached from the task group to investigate the whereabouts of U-804, which both had made contact with. Upon sighting the destroyers, the U-boat quickly dived, but the two escorts detected her on their sonar and began their attack approach. Suddenly, USS Fiske was torpedoed on her starboard side by U-804, and within 10 minutes, she broke in two. Thirty-three of her men were killed and 50 were wounded, but all the survivors were rescued by USS Farquhar (DE-139). Amidst the confusion following the sinking of USS Fiske, U-804 slipped away and returned to her patrol.

Second patrol & loss
On 12 October 1944, U-804 returned to the port of Flensburg after 116 days at sea. Five days later she left Flensburg for Kiel, where she remained until 4 April 1945 before leaving for occupied Norway. While en route in company with another of the flotilla's boats, GS U-1065, the two submarines were detected and attacked in the Skagerrak strait on 9 April 1945 by over 30 Mosquito aircraft from three Royal Air Force squadrons based at Banff. U-1065 succeeded in shooting down one of the attacking aircraft before being hit by several rockets fired by 10 Mosquitos from 143 and 235 Squadrons; she exploded and sank with the loss of her crew of 45 men.

U-804 suffered the same fate - after being hit by rockets from the attacking Mosquitos she also exploded and sank at 57.96667°N, 11.25°W, with no survivors from her crew of 55 men.