U-1228 surrenders at Portsmouth, New Hampshire (USA), on 17 May 1945
|Ordered:||14 October 1941|
|Builder:||Deutsche Werft AG, Hamburg|
|Laid down:||16 February 1943|
|Launched:||2 October 1943|
|Commissioned:||22 December 1943|
|Fate:||sunk 5 February 1946 by US warships in position Coordinates: |
|Class and type:||Type IXC/40 submarine|
|Height:||9.60 m (31 ft 6 in)|
|Draught:||4.67 m (15 ft 4 in)|
|Test depth:||230 m (750 ft)|
|Complement:||4 officers, 44 enlisted|
|Identification codes:||M 55 286|
|Commanders:||Oblt.z.S. Friedrich-Wilhelm Marienfeld|
German Type IXC/40 submarines were slightly larger than the original Type IXCs. U-1228 had a displacement of 1,144 tonnes (1,126 long tons) when at the surface and 1,257 tonnes (1,237 long tons) while submerged. The U-boat had a total length of 76.76 m (251 ft 10 in), a pressure hull length of 58.75 m (192 ft 9 in), a beam of 6.86 m (22 ft 6 in), a height of 9.60 m (31 ft 6 in), and a draught of 4.67 m (15 ft 4 in). The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of 4,400 metric horsepower (3,240 kW; 4,340 shp) for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of 1,000 shaft horsepower (1,010 PS; 750 kW) for use while submerged. She had two shafts and two 1.92 m (6 ft) propellers. The boat was capable of operating at depths of up to 230 metres (750 ft).
The submarine had a maximum surface speed of 18.3 knots (33.9 km/h; 21.1 mph) and a maximum submerged speed of 7.3 knots (13.5 km/h; 8.4 mph). When submerged, the boat could operate for 63 nautical miles (117 km; 72 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 13,850 nautical miles (25,650 km; 15,940 mi) at 10 knots (19 km/h; 12 mph). U-1228 was fitted with six 53.3 cm (21 in) torpedo tubes (four fitted at the bow and two at the stern), 22 torpedoes, one 10.5 cm (4.13 in) SK C/32 naval gun, 180 rounds, and a 3.7 cm (1.5 in) Flak M42 as well as two twin 2 cm (0.79 in) C/30 anti-aircraft guns. The boat had a complement of forty-eight.
U-1228 was ordered in October 1941 from Deutsche Werft in Hamburg-Finkenwerder under the yard number 391. Her keel was laid down on 16 February 1943 and the U-boat was launched on 2 October. About three months later she was commissioned into service under the command of Oberleutnant zur See Friedrich-Wilhelm Marienfeld (Crew X/38) in the 31st U-boat Flotilla.
After work-up for deployment, U-1228 transferred to the 2nd U-boat Flotilla and left Kiel for the West Atlantic on 5 September 1944 for her first and only patrol. Stopping briefly in Bergen, Norway, for replenishment, she experienced engine troubles in the Norwegian Sea and had to return to port. She set off again on 12 October from Bergen and operated south of Nova Scotia sinking one warship, HMCS Shawinigan.
She returned to Bergen on 28 December 1944 and continued her journey to Flensburg the same day. On 17 January 1945, she arrived in Wesermünde where she spent the next two months in the yard. U-1228 set out again on 1 April 1945 for operations in the West Atlantic. After the surrender of Germany, the U-boat made for the closest Allied port and surrendered to US forces in Portsmouth, New Hampshire on 17 May 1945.