Ship ClassType IX-class Submarine
BuilderDeutsche Werft Hamburg
Yard Number396
Ordered14 Oct 1941
Laid Down29 Apr 1943
Launched23 Dec 1943
Commissioned22 Mar 1944
Sunk29 Dec 1945
Displacement1,144 tons standard; 1,257 tons submerged
Length252 feet
Beam23 feet
Draft15 feet
MachineryTwo MAN M 9 V 40/46 supercharged 4-stroke 9cyl diesel engines (4,300bhp), 2 Siemens-Schuckert 2 GU 345/34 double-acting electric motors (990shp), two shafts, two 1.92m propellers
Speed18 knots
Range13,850nm at 10 knots surfaced, 63nm at 4 knots submerged
Armament4x53.3cm bow torpedo tubes, 2x53.3cm stern torpedo tubes, 22 torpedoes, 1x10.5cm SK C/32 gun, 1x3.7cm Flak M42 anti-aircraft gun, 2x2x2cm C/30 anti-aircraft guns
Submerged Speed7.3 knots


ww2dbaseU-1233 was commissioned into German naval service under the command of KorvettenkapitÀn Hans-Joachim Kuhn in Mar 1944. She was assigned to the 31st Submarine Flotilla for training before being transferred to the 33rd Submarine Flotilla for front line duty. After completing a war patrol out of Horten, Norway, Oberleutnant zur See Heinrich Niemeyer relieved Kuhn as the boat's commanding officer. In May 1945, she was ordered to set sail together with U-155 and U-680 for Fredericia, Denmark in preparation for surrender; en route, the group was attacked by British aircraft, and they shot down one P-51 Mustang fighter of No. 126 Squadron RAF. In Jun 1945, she was transferred to Wilhelmshaven, Germany by the British, from where she would sail, together with other captured ships, to Loch Ryan in southwestern Scotland, United Kingdom. She was towed out to sea in Dec 1945 and sunk by gunfire from destroyer HMS Onslaught as a part of Operation Deadlight.


Last Major Revision: Nov 2021

Submarine U-1233 Interactive Map

U-1233 Operational Timeline

14 Oct 1941 The order for the construction of U-1233 was issued.
29 Apr 1943 The keel of U-1233 was laid down at the Deutsche Werft yard in Hamburg, Germany.
23 Dec 1943 U-1233 was launched at the Deutsche Werft yard in Hamburg, Germany.
22 Mar 1944 U-1233 was commissioned into service under the command of KorvettenkapitĂ€n Hans-Joachim Kuhn and was assigned to 31st Submarine Flotilla.
1 Nov 1944 U-1233 was transferred to 33rd Submarine Flotilla.
18 Nov 1944 U-1233 departed Kiel, Germany.
24 Nov 1944 U-1233 arrived at Bergen, Norway.
11 Dec 1944 U-1233 departed Horten, Vestfold, Norway for her first and only war patrol.
16 Dec 1944 U-1233 arrived at Bergen, Norway, ending her first and only war patrol.
17 Dec 1944 U-1233 departed Bergen, Norway.
21 Dec 1944 U-1233 arrived at Bergen, Norway.
31 Mar 1945 U-1233 departed Kristiansand, Vest-Agder, Norway.
3 Apr 1945 U-1233 arrived at Flensburg, Schleswig-Holstein, Germany.
15 Apr 1945 Oberleutnant zur See Heinrich Niemeyer was named the commanding officer of U-1233, relieving Hans-Joachim Kuhn.
5 May 1945 U-1233 surrendered to the Allieds in BĂ„ring Bay near Fredericia, Denmark.
28 Dec 1945 U-1233 was towed into the Atlantic Ocean from Loch Ryan, Scotland, United Kingdom by HMS Freedom.
29 Dec 1945 U-1233 was sunk in the Atlantic Ocean by gunfire from HMS Onslaught about 40 miles northwest of Ireland.

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