German submarine U-1225

German submarine U-1225 was a Type IXC/40 U-boat of Nazi Germany's Kriegsmarine during World War II.

The submarine was laid down on 28 December 1942 at the Deutsche Werft yard at Hamburg, launched on 21 July 1943, and commissioned on 10 November 1943 under the command of Oberleutnant zur See Ernst Sauerberg. The U-boat then served with 31st U-boat Flotilla, a training unit, until 31 May 1944. She was then transferred to the 2nd U-boat Flotilla for active service.

Design
German Type IXC/40 submarines were slightly larger than the original Type IXCs. U-1225 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-1225 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.

Service history
U-1225 had a short but active career. She departed Kristiansand on 20 June 1944, never to return. Four days out of port, the new submarine was attacked by Canso aircraft of No. 162 Squadron RCAF. The flying boat was shot down, but not before her depth charges fatally wounded the U-boat. All 56 sailors went down with the sub. Three of the eight aircrew from the Catalina were lost as well. The pilot, David Ernest Hornell, was awarded a posthumous Victoria Cross.