German submarine U-1230 was a Type IXC/40 U-boat of Nazi Germany's Kriegsmarine during World War II.
Laid down on 15 March 1943 at the Deutsche Werft in Hamburg, and commissioned on 26 January 1944 under the command of Kapitänleutnant Hans Hilbig, it only undertook one patrol, operating from Horten Naval Base, Norway, returning safely to Kristiansand, Norway in early 1945.
German Type IXC/40 submarines were slightly larger than the original Type IXCs. U-1230 had a displacement of 1144t when at the surface and 1257t while submerged. The U-boat had a total length of 76.76m (251.84feet), a pressure hull length of 58.75m (192.75feet), a beam of 6.86m (22.51feet), a height of 9.6m (31.5feet), and a draught of 4.67m (15.32feet). The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of 4400PS for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of 1000shp for use while submerged. She had two shafts and two 1.92abbr=onNaNabbr=on propellers. The boat was capable of operating at depths of up to .
The submarine had a maximum surface speed of and a maximum submerged speed of . When submerged, the boat could operate for at ; when surfaced, she could travel at . U-1230 was fitted with six 53.30NaN0 torpedo tubes (four fitted at the bow and two at the stern), 22 torpedoes, one 10.52NaN2 SK C/32 naval gun, 180 rounds, and a 3.7cm (01.5inches) Flak M42 as well as two twin 2sp=usNaNsp=us C/30 anti-aircraft guns. The boat had a complement of forty-eight.
Its one war patrol was of historical interest less for its role in the Battle of the Atlantic (a Canadian steamer of 5,458 Gross register tonnage was its sole victim), than for its role in transporting two German spies to the United States.
William Curtis Colepaugh and Eric Gimpel were landed at Hancock Point in the Gulf of Maine on 29 November 1944 in Operation Elster ("Magpie"). The mission was intended to gather technical intelligence but failed, and both spies were captured.
At the end of the war it was captured by the Allies, transferred to Loch Ryan in Scotland, and sunk on 17 December 1945 by the Royal Navy frigate as part of "Operation Deadlight". Unusually for a U-boat, U-1230 does not seem to have suffered any casualties during the war.