# German submarine U-1023

German submarine U-1023 was a Type VIIC/41 U-boat of Nazi Germany's Kriegsmarine. She was laid down on 20 May 1943 by Blohm & Voss in Hamburg, Germany, and commissioned on 15 June 1944 with Oberleutnant Wolfgang Strenger in command. U-1023 sank one ship and damaged one more for a total of 7,345 GRT and 335 tons. After the war she was sunk in Operation Deadlight.

## Design

German Type VIIC/41 submarines were preceded by the heavier Type VIIC submarines. U-1023 had a displacement of 759 tonnes (747 long tons) when at the surface and 860 tonnes (850 long tons) while submerged. She had a total length of 67.10 m (220 ft 2 in), a pressure hull length of 50.50 m (165 ft 8 in), a beam of 6.20 m (20 ft 4 in), a height of 9.60 m (31 ft 6 in), and a draught of 4.74 m (15 ft 7 in). The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2,800 to 3,200 metric horsepower (2,060 to 2,350 kW; 2,760 to 3,160 shp) for use while surfaced, two Brown, Boveri & Cie GG UB 720/8 double-acting electric motors producing a total of 750 metric horsepower (550 kW; 740 shp) for use while submerged. She had two shafts and two 1.23 m (4 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 17.7 knots (32.8 km/h; 20.4 mph) and a maximum submerged speed of 7.6 knots (14.1 km/h; 8.7 mph). When submerged, the boat could operate for 80 nautical miles (150 km; 92 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 8,500 nautical miles (15,700 km; 9,800 mi) at 10 knots (19 km/h; 12 mph). U-1023 was fitted with five 53.3 cm (21 in) torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm (3.46 in) SK C/35 naval gun, (220 rounds), one 3.7 cm (1.5 in) Flak M42 and two 2 cm (0.79 in) C/30 anti-aircraft guns. The boat had a complement of between forty-four and sixty.

## Armament
### FLAK weaponry

U-1023 was mounted with a single 3.7 cm Flakzwilling M43U gun on the rare LM 43U mount. The LM 43U mount was the final design of mount used on U-boats and is only known to be installed on U-boats (U-249, U-826, U-977, U-1171, U-1305 and U-1306). The 3.7 cm Flak M42U was the marine version of the 3.7 cm Flak used by the Kriegsmarine on Type VII and Type IX U-boats. U-1023 was mounted with two 2cm Flak C38 in a M 43U Zwilling mount with short folding shield on the upper Wintergarten. The M 43U mount was used on a number of U-boats (U-190, U-250, U-278, U-337, U-475, U-853, U-1058, U-1109, U-1105, U-1165 and U-1306).
* The single 3.7 cm Flak M42U gun on the LM 43U mount.
* 2 cm Flak C38 in a M 43U Zwilling mount with short folding shield.

## Service history

U-1023 was ordered by the Kriegsmarine on 13 June 1942. She was laid down about one year later at Blohm & Voss, Hamburg on 20 May 1943. Almost a year later, U-1023 was launched from Hamburg on 3 May 1944. She was formally commissioned later that year on 15 June. U-1023 carried 5 × 53.3 cm (21 in) torpedo tubes (4 located in the bow, 1 in the stern) and had one 8.8 cm (3.46 in) deck gun with 220 rounds. She could also carry 14 G7e torpedoes or 26 TMA mines and had a crew of 44–52 men. She was one of the U-boats that used the Schnorchel underwater breathing apparatus.
After her redesignation as a front-line U-boat, U-1023 left port on her first and only patrol. By that time, she had moved from Kiel to her later location in Bergen via a stopover in Horten Naval Base. After leaving on 25 March 1945 for her first patrol, U-1023 intercepted and attacked Riverton, a 7,345 GRT British steam merchant on 23 April. She was damaged and beached off St. Ives Bay. Later, on 7 May 1945, the last day of the war in Europe, U-1023 found the 335 tons Norwegian minesweeper HNoMS NYMS 382, which was sunk with 22 dead.

### Fate

U-1023 was surrendered at Weymouth, England on 10 May 1945. After the war she was paraded up the west coast of the UK visiting a number of ports including Plymouth, Brixham, Falmouth, Bristol, Swansea, Liverpool, Holyhead, Manchester, Fleetwood, Belfast, Glasgow, Greenock, Rothsay, Oban. Several hundred thousand visitors were given a tour of the boat during this time. U-1023 was then used in Operation Deadlight and sunk by the Allies on 7 January 1946.

## Summary of raiding history

| Date | Ship Name | Nationality | Tonnage | Fate |
| 23 April 1945 | Riverton | United Kingdom | 7,345 | Damaged |
| 7 May 1945 | HNoMS NYMS-382 | Royal Norwegian Navy | 335 | Sunk |