| History | |
|---|---|
 Nazi Germany | |
| Name | U-91 |
| Ordered | 25 January 1939 |
| Builder | Flender Werke,Lübeck |
| Yard number | 295 |
| Laid down | 12 November 1940 |
| Launched | 30 November 1941 |
| Commissioned | 28 January 1942 |
| Fate | Sunk, 26 February 1944 |
| General characteristics | |
| Class & type | Type VIIC submarine |
| Displacement | |
| Length |
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| Beam |
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| Height | 9.60 m (31 ft 6 in) |
| Draught | 4.74 m (15 ft 7 in) |
| Installed power |
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| Propulsion |
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| Speed |
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| Range | |
| Test depth |
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| Complement | 4 officers, 40–56 enlisted |
| Armament |
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| Service record | |
| Part of |
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| Identification codes | M 08 626 |
| Commanders | |
| Operations |
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| Victories |
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German submarineU-91 was aType VIICU-boat ofNazi Germany'sKriegsmarine duringWorld War II.
She waslaid down at theFlender Werke inLübeck as yard number 295,launched on 30 November 1941 andcommissioned on 28 January 1942 withOberleutnant zur See Heinz Walkerling as commanding officer. Command was transferred toOblt.z.S. Heinz Hungershausen on 20 April 1943.
She was a fairly successful boat, sinking over 26,000 tons of Allied shipping in a career lasting just 14 months and six patrols. She was a member of fifteenwolfpacks. After training with the5th U-boat Flotilla,U-91 was assigned to the9th flotilla on 1 September 1942 for operations.
German Type VIIC submarines were preceded by the shorterType VIIB submarines.U-91 had a displacement of 769 tonnes (757 long tons) when at the surface and 871 tonnes (857 long tons) while submerged.[1] She had a total length of 67.10 m (220 ft 2 in), apressure hull length of 50.50 m (165 ft 8 in), abeam of 6.20 m (20 ft 4 in), a height of 9.60 m (31 ft 6 in), and adraught of 4.74 m (15 ft 7 in). The submarine was powered by twoGermaniawerft F46 four-stroke, six-cylindersuperchargeddiesel 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, twoBrown, Boveri & Cie GG UB 720/8double-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).[1]
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).[1] 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-91 was fitted with five 53.3 cm (21 in)torpedo tubes (four fitted at the bow and one at the stern), fourteentorpedoes, one8.8 cm (3.46 in) SK C/35 naval gun, 220 rounds, and a2 cm (0.79 in) C/30 anti-aircraft gun. The boat had acomplement of between forty-four and sixty.[1]
U-91 departedKiel for her first patrol on 15 August 1942. Having negotiated theIceland/Faroes 'gap', she was attacked by a USPBY Catalina on 1 September. (This incident was originally thought to have been againstU-756).
The escort vessels ofconvoy ON 127 fired on the boat on 12 September; minor damage was sustained.
U-91 sank the Canadian destroyerHMCS Ottawa on 14 September. The boat fired twotorpedoes at 02:05 and confirmed a hit. At 02:15, the submarine came across the damagedOttawa once again, but mistook her for a different vessel and fired a third torpedo, which destroyed the ship, killing 114 of the 181 men aboard.[2]
She also sankNew York southeast ofCape Farewell (Greenland) on 26 September.
She docked inBrest, on the French Atlantic coast, on 6 October.
The boat's second foray started from Brest on 1 November 1942 and finishing there on 26 December. It was relatively uneventful.
U-91 was subject to a "rain of aircraft bombs and depth charges from surface ships" which obliged her to break off an attack to carry out repairs on 21 February 1943.
The boat was soon back in action; on 17 March,U-91 attackedConvoy HX 229. Two American vessels -SS Harry Luckenbach andIrénée Du Pont - were destroyed along with the British merchant shipNariva. TheLuckenbach was hit by two torpedoes after five were fired between 03:37 and 03:41.Luckenbach sank in a mere three minutes, with seventy-one of the eighty men evacuating in lifeboats, although there were no reports of them being rescued.Nariva andIrénée Du Pont had been damaged byU-600 earlier that day.U-91 fired three torpedoes at 05:56: Two finishing offDu Pont, a third crippledNariva.[3]
The inbound submarine was attacked by aLeigh Light equippedVickers Wellington ofNo. 172 Squadron RAF on the western edge of theBay of Biscay on 27 March. Although not damaged, the boat dived with three men still top-side. Two were recovered, but the third could not be found.
U-91 returned to France, but toLorient, on 29 March.
Sortie number four began from Lorient on 29 April 1943; it was also relatively quiet but terminated in Brest on 7 June.
U-91 was attacked by aB-24 Liberator ofNo. 10 Squadron RCAF on 26 October 1943. The undamaged U-boat had been searching forU-584 to supply her with fuel. The Liberator's assault was thought to have sunkU-420. A few days later, (on the 31st), having foundU-584, she commenced the re-fuelling operation, but the two boats were spotted by aircraft from the escort carrierUSS Card. In the ensuing mayhem,U-91 escaped without damage after diving;U-584 was not so lucky, she was sunk.
U-91 departed Brest for the last time on 25 January 1944; on 26 February she was sunk in the middle of the North Atlantic by depth charges from the BritishfrigatesHMS Affleck,HMS Gore andHMS Gould.
36 men died with the U-boat includingKapitänleutnant Heinz Hungershausen; there were 16 survivors.
| # | Departure | Date | Arrival | Date | Length |
|---|---|---|---|---|---|
| 1 | Kiel | 15 August 1942 | Brest | 6 October 1942 | 53 days |
| 2 | Brest | 1 November 1942 | Brest | 26 December 1942 | 56 days |
| 3 | Brest | 11 February 1943 | Lorient | 29 March 1943 | 47 days |
| 4 | Lorient | 29 April 1943 | Brest | 7 June 1943 | 40 days |
| 5 | Brest | 21 September 1943 | Brest | 22 November 1943 | 63 days |
| 6 | Brest | 25 January 1944 | Sunk | 26 February 1944 | 33 days |
U-91 took part in 15wolfpacks, namely:
| Date | Ship | Nationality | Tonnage[Note 1] | Fate[4] |
|---|---|---|---|---|
| 14 September 1942 | HMCS Ottawa |  Royal Canadian Navy | 1,375 | Sunk |
| 26 September 1942 | New York |  United Kingdom | 4,989 | Sunk |
| 17 March 1943 | Harry Luckenbach |  United States | 6,366 | Sunk |
| 17 March 1943 | Irénée Du Pont | United States | 6,125 | Sunk |
| 17 March 1943 | Nariva | United Kingdom | 8,714 | Sunk |
Shipwrecks and maritime incidents in February 1944 | |
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| Shipwrecks |
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| Other incidents |
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