View source for British U-class submarine

{{Short description|1940 class of British submarines}}
{{Distinguish|U-boat}}
{{Use dmy dates|date=January 2017}}
{{Use British English|date=January 2017}}
{|{{Infobox ship begin
| sclass = 2
}}
{{Infobox ship image
| Ship image = HMS Ultimatum.jpg
| Ship caption = U-class submarine {{HMS|Ultimatum|P34|6}} departing [[Holy Loch]], August 1943
}}
{{Infobox ship class overview
| Name = U class
| Builders =
| Operators = *{{navy|United Kingdom}}
* {{navy|Poland}}
* {{navy|Free France}}
* {{navy|Soviet Union}}
* {{navy|Netherlands}}
* {{navy|Denmark}}
* {{navy|Greece}}
* {{navy|Norway}}
| Class before = [[British T-class submarine|T class]]
| Class after = [[British V-class submarine|V class]]
| Subclasses =
| Cost =
| Built range =
| In service range =
| In commission range =
| Total ships building =
| Total ships planned =
| Total ships completed = 49
| Total ships cancelled =
| Total ships active =
| Total ships laid up =
| Total ships lost =
| Total ships retired =
| Total ships preserved =
}}
{{Infobox ship characteristics
| Hide header =
| Header caption =
| Ship class =
| Ship type = [[Submarine]]
| Ship tonnage =
| Ship displacement = *{{cvt|540|LT}} standard, {{cvt|630|LT}} full load surfaced
* 730 tons submerged
| Ship length = {{cvt|191|ft}}
| Ship beam = {{cvt|16|ft|1|in}}
| Ship height =
| Ship draught = {{cvt|15|ft|2|in}}
| Ship draft =
| Ship depth =
| Ship hold depth =
| Ship decks =
| Ship deck clearance =
| Ship ramps =
| Ship ice class =
| Ship power =
| Ship propulsion = *2 shaft diesel-electric
* 2 Paxman Ricardo diesel generators + electric motors
* {{cvt|615|hp}}, {{cvt|825|hp}}
| Ship sail plan =
| Ship speed = *{{cvt|11.25|kn}} surfaced
* {{cvt|10|kn|mph+km/h}} submerged
| Ship range = {{cvt|4500|nmi}} at {{cvt|11|kn}} surfaced
| Ship endurance =
| Ship test depth =
| Ship boats =
| Ship capacity =
| Ship troops =
| Ship complement = 27 to 31
| Ship crew =
| Ship time to activate =
| Ship sensors =
| Ship EW =
| Ship armament = *6 × [[British 21 inch torpedo|21 inch (533 mm)]] [[torpedo tube]]s - 4 bow internal, 2 bow external (first group only) 8–10 [[torpedo]]es
* 1 × [[QF 3 inch 20 cwt]] {{cvt|3|in}} gun
| Ship armour =
| Ship armor =
| Ship aircraft =
| Ship aircraft facilities =
| Ship notes =
}}
|}

The British '''U-class submarines''' (officially "''War Emergency 1940 and 1941 programmes, short hull''"){{sfn|Chesneau|1992|p=50}} were a class of 49 small submarines built just before and during the [[Second World War]]. The class is sometimes known as the ''Undine'' class, after the first submarine built. A further development was the [[British V-class submarine]] of 1942.

At the start of the Second World War the ''U'' class was together with the British [[British S-class submarine (1931)|''S'']] and [[British T-class submarine|''T'' class]], Dutch [[O 21-class submarine|''O 21'' class]] and German [[Type VII submarine|''Type VII'' class]] one of the most advanced submarine classes in service at the time.<ref>van den Pol (1989), p. 352.</ref>

==Background==
The Royal Navy was limited to no more than {{cvt|52700|LT}} of submarines by the [[London Naval Treaty]] of 1930. The tonnage limit led to proposals for smaller submarines which was also prompted by trials with larger submarines demonstrating that they were easier to find and lacked manoeuvrability. By coincidence the [[First World War]]-vintage [[British H-class submarine|H-class]] submarines used for training in anti-submarine warfare were reaching the end of their useful service. The Rear-Admiral Submarines, [[Noel Laurence]], wanted a class of small, inexpensive boats for training, armed with torpedoes for short-range patrols.{{sfn|Walters|2004|p=2}}

In March 1934 he approved a specification for a "Small, Simple, Submarine, for Anti-Submarine Training etc".{{sfn|Walters|2004|p=2}} The three ''Unity''-class boats, {{HMS|Undine|N48|6}}, {{HMS|Unity|N66|2}} and {{HMS|Ursula|N59|2}} were ordered on 5 November 1936 from [[Vickers-Armstrongs]], to be built at their Naval Construction Yard in [[Barrow-in-Furness]]. According to the recommendation of the [[Ronald Hopwood|Hopwood Committee]] of 1926 the boats had names beginning with the same letter in the alphabet. {{sfnm|1a1=Walters|1y=2004|1p=2|2a1=Chesneau|2y=1992|2p=50}} The new boats were the smallest built since the First World War.{{sfn|Walters|2004|p=3}}{{efn|The weight of a submarine when under water must always equal the buoyancy. Extra weight has to be compensated for by removing an equal amount of ballast, which is near the keel causing the centre of gravity to rise. Buoyancy is also dependent on the density of the water around the boat. Before the [[Second World War]] submarines were designed to operate in waters with densities from fresh to highly saline.{{sfn|Brown|2012|p=191}}}}

== Design and development ==

The U-class boats had a hull of riveted steel, half-an-inch thick for dives to {{cvt|200|ft}}, with the fuel tanks and ballast tanks on the inside. The superstructure and conning tower were built with free-flooding holes and storage for cables, anchors and sundry items. The hull was divided by five bulkheads with access from the conning tower; hatches in the torpedo-stowage compartment and in the engine room had drop-down canvas trunks for emergencies.{{sfn|Walters|2004|p=6}}{{efn|After closing all water-tight doors, the trunks were lowered and connected to the deck. The hatch was opened slightly until the air–water pressure was equal, the crew breathing the trapped air until escaping. Each crewman had a [[Davis Submerged Escape Apparatus]] of a nose-clip and mouthpiece connected to an oxygen bag. The first man in the trunking opened the hatch and left the boat, followed by the others in turn. Escape from the conning tower was by two men entering the tower, closing the lower hatch then opening the upper one to flood the space then leaving.{{sfn|Walters|2004|p=6}}}} The boats had an {{cvt|8|in}} bifocal periscope with high/low magnification for searching and a {{cvt|6|in}} low magnification periscope for attack.{{sfn|Walters|2004|p=6}}

The periscopes could rise {{cvt|12|ft}} but such a shallow periscope depth could allow the boat to be seen from the air. Hydrophones were fitted, one on each side near the bows facing outwards and one on the conning tower facing aft. [[Sonar#Asdic|Asdic]] Type 129 was installed forward of the keel from 1937 and two wireless aerials were carried, a jumping aerial on the conning tower for [[very low frequency]] signals at periscope depth and a [[Wireless telegraphy|WT]] mast which could be raised above the water spread the second aerial for conventional wireless signalling.{{sfn|Walters|2004|pp=6–7}}

The boats had six ordinary ballast tanks and a quick-diving, ''Q tank'', the ballast tanks, hydroplanes and the rudder being hydraulically operated; the forward hydroplanes were mounted high on the hull and folded upwards for docking. The submarines had two {{cvt|400|hp}} [[Paxman (engines)|Paxman]] diesel-electric engines generating {{cvt|615|bhp}} and [[electric motors]] of {{cvt|825|shp}} giving a surface speed of {{cvt|11.25|kn}} and a submerged speed of {{cvt|10|kn}}. The diesels were linked to the propellers by two generators which kept charged the battery of 112 cells under the control room and crew accommodation.{{sfnm|1a1=Chesneau|1y=1992|1p=50|2a1=McCartney|2y=2006|2p=14}} Submarine propellers had been designed to perform best on the surface until the ''Unity-class'' which was the first submarine design with propellers giving their best performance submerged to reduce propeller noise but [[cavitation|"singing propellers"]] were a constant problem for the class.{{sfn|Brown|2012|p=189}}

The boats had a fuel capacity of {{cvt|38|LT}} giving a range of {{cvt|3800|nmi}} at {{cvt|10|kn}} on the surface and {{cvt|120|nmi}} at {{cvt|2|kn}} submerged; battery recharging required the submarine to surface; in 1944 dummy snorkels were fitted to some boats for anti-submarine warfare training{{sfn|Walters|2004|pp=3–4}} During construction the four internal bow [[torpedo tubes]] were supplemented by two external tubes in a bulged housing, four reloads being carried for the internal tubes. ''Ursula'' carried a {{cvt|3|in}} gun but had no hatch for the gun crew, who had to use the conning tower; to compensate for the weight of the gun only eight torpedoes were carried. Just before the war, a second group of twelve vessels were ordered, {{HMS|Unique|N95|6}}, {{HMS|Upholder|N99|6}}, {{HMS|Upright|N89|6}} and {{HMS|Utmost|N19|6}} with the external tubes, the others without, because the bulge at the bow generated a large [[bow wave]]. Depth keeping was more difficult at [[periscope depth]], a rather shallow {{cvt|12|ft}} which was more of a disadvantage than the six-torpedo salvo justified. The sudden loss of weight in the bows when the torpedoes were loosed in [[salvo]] made the boat porpoise and break the surface.{{sfnm|1a1=McCartney|1y=2006|1p=14|2a1=Chesneau|2y=1992|2p=50}}

== ''Unity''-class boats ==
[[File:Shadowgraph U british class groupe I submarine.svg|thumb|left|{{center|Group one boats}}]]
The three ''Unity-class'' boats entered service in the latter half of 1938. Designed as training vessels, they were effective enough to persuade the [[Admiralty (United Kingdom)|Admiralty]] to build more and to improve their offensive capacity. ''Ursula'' was launched on 16 February 1938, was loaned to the [[Soviet Navy]] from 1944 to 1949 as ''V 4'' and sold in May 1950 and broken up. ''Unity'' was launched on 16 February 1938 and sunk on 29 April 1940 in a collision with ''SS Atle Jarl'' off the Tyne. ''Undine'' was launched on 5 October 1937 and sunk by German minesweepers on 7 January 1940 off [[Heligoland]].{{sfn|Colledge|Wardlow|2006|pp=367, 366, 365}}

{| class = "wikitable sortable"
|+ ''Unity''-class boats [Data from Chesneau (1992), Colledge and Wardlow (2006)]
|-
!Name/<br>No.
!Launched
! Notes
|-
| {{HMS|Undine|N48|6}} ||align="center"|5 October 1937 || Sunk by German minesweepers off Heligoland, 7 January 1940{{sfnm|1a1=Chesneau|1y=1992|1p=50|2a1=Colledge|2a2=Wardlow|2y=2006|2p=365}}
|-
| {{HMS|Unity|N66|6}} ||align="center"|16 February 1938 || Sunk in collision with SS ''Alte Jarl'' 29 April 1940{{sfnm|1a1=Chesneau|1y=1992|1p=50|2a1=Colledge|2a2=Wardlow|2y=2006|2p=366}}
|-
| {{HMS|Ursula|N59|6}} ||align="center"|16 February 1938 || Loaned to [[Soviet Navy]] 1944–1949, sold 1950, broken up{{sfnm|1a1=Chesneau|1y=1992|1p=50|2a1=Colledge|2a2=Wardlow|2y=2006|2p=367}}
|-
|}
{{clear}}

== Group II boats ==
{|{{Infobox ship begin|sclass=2}}
{{Infobox ship image
|Ship image= File:Shadowgraph U british class groupe II submarine.svg
|Ship caption=Group Two boats
}}
{{Infobox ship class overview
|Name='''Group two'''
|Builders=
|Operators=
|Class before=
|Class after=
|Subclasses=
|Cost=
|Built range=
|In service range=
|In commission range=
|Total ships building=
|Total ships planned=
|Total ships completed=12
|Total ships cancelled=
|Total ships active=
|Total ships laid up=
|Total ships lost=9
|Total ships retired=
|Total ships preserved=
}}
{{Infobox ship characteristics
|Hide header=
|Header caption=
|Ship type=Submarine
|Ship displacement={{Unbulleted list| 630 tons surfaced, 732 tons submerged
|1940–1941 boats 658 tons surfaced, 740 tons submerged
}}
|Ship length={{cvt|191|ft}}{{efn|{{cvt|192|ft}}: ''Undaunted'', ''Unon'', ''Urchin'' and ''Urge''; {{cvt|197|ft}} ''Umpire'', ''Una'' after modification, ''Unbeaten'' and ''Unique''{{sfn|McCartney|2006|p=16}}}}
|Ship beam={{cvt|16|ft}}
|Ship draught={{cvt|10|ft}}
|Ship power={{cvt|615|bhp}}
|Ship propulsion=
|Ship speed={{Unbulleted list| {{cvt|11.25|kn}} surfaced
| {{cvt|9|kn}} submerged
}}
|Ship range={{cvt|3800|mi}} at {{cvt|10|kn}},  1940 and 1941 boats {{cvt|5000|mi}} at {{cvt|10|kn}}
|Ship endurance={{cvt|120|mi}} submerged
|Ship test depth={{cvt|200|ft}}
|Ship complement=36 officers and enlisted
|Ship sensors=
|Ship EW=
|Ship armament={{Unbulleted list|bow 4 × [[British 21 inch torpedo|21-inch (533 mm)]] [[torpedo tube]]s (8 × [[torpedo]]es)
|(later, 6 mines)
|1 × [[QF 12-pounder 12 cwt naval gun|QF 12-pounder]]{{efn|''Unbeaten'' and ''Unique'' later received 3-inch guns, all boats ordered 1940–1941 had 3-inch guns{{sfn|McCartney|2006|p=16}}}}
| 2, later 3 × .303-calibre machine-guns
}}
|Ship armour=
|Ship notes=maximum complement 33{{efn|Data from McCartney (2006){{sfn|McCartney|2006|p=16}}}}
}}
|}
The experience gained with the ''U''-class boats was incorporated into the Group two boats of the War Supplementary Emergency Programme, consisting of twelve submarines, of a similar design to the original three. The external torpedo tubes were omitted and the boats had a redesigned stern to reduce cavitation and on some of the boats a new bow shape was introduced to reduce the bow wave; the hydroplanes were enlarged for better submerged handling. The First World War-vintage 12-pounder was retained but replaced on ''Unbeaten'' and ''Unique'' by a 3-inch gun. The boats ordered in 1940 and 1941 carried the 3-inch gun and more fuel. Most of the boats were built by Vickers at Barrow-in-Furness. [[MI5]] investigated the loss of ''Vandal'' and ''Untamed'' during training operations but the report was kept confidential.{{sfn|McCartney|2006|p=16}}

In June 1940 the Admiralty had stopped naming submarines and known them by their pennant numbers but on 4 November 1942 the Prime Minister, Winston Churchill, questioned the policy. The First Lord of the Admiralty replied that naming had been dropped to avoid confusion with the big increase in the number of destroyers, which usually had names with the same initial letter. Numbering submarines had been the practise in the First World War but that because of Churchill's views, the Admiralty had decided that it was better to be right than consistent and that naming was to be resumed. After a delay Churchill was told that it was difficult to find sufficient names beginning with ''U'' and that the surplus were being named with words beginning with ''V'' and a list was sent to Churchill on 27 December 1942. Submarines lost before they could receive names kept their pennant number.{{sfn|Walters|2004|pp=11–12}}

The group included submarines that became well-known; ''Urchin'' was transferred to the [[Polish Navy]] as {{ORP|Sokół||6}} and sank {{cvt|55000|LT}} of Axis shipping. In the 16-month operational career of {{HMS|Upholder|P37|6}} ([[Lieutenant commander (Royal Navy)|Lieutenant-Commander]] [[Malcolm David Wanklyn|Malcolm Wanklyn]]) in the Mediterranean, ''Upholder'' carried out 24 patrols and sank around {{cvt|119000|LT}} of Axis ships, consisting of three U-boats, a destroyer, 15 merchant ships with possibly a cruiser and another destroyer also sunk before being lost in April 1942. Wanklyn was awarded the [[Victoria Cross]] for attacking a well-defended [[convoy]] and sinking the Italian [[Ocean liner|liner]] {{SS|Conte Rosso||2}} on 25 May 1941. Losses in this group were high, only three out of the twelve survived the war.{{sfn|McCartney|2006|p=15}}
{{clear}}
===4 September 1939 batch===
{| class = "wikitable sortable"
|+ Group II boats [Data from Walters (2004), Colledge and Wardlow (2006)]
|-
!Name/<br>No.
!Ordered
! Notes
|-
| {{HMS|Umpire|N82|6}} ||align="center"|4 September 1939 || Rammed accidentally and sunk by trawler ''Peter Hendriks'', 17 July 1941, [[North Sea]], 22 killed{{sfnm|1a1=Colledge|1a2=Wardlow|1y=2006|1p=364|2a1=Walters|2y=2004|2p=9}}
|-
| {{HMS|Una|N87|6}} ||align="center"|4 September 1939 || Sold 11 April 1949, broken up{{sfn|Colledge|Wardlow|2006|p=364}}
|-
| {{HMS|Unbeaten|N93|6}} ||align="center"|4 September 1939 || Sunk by British bomber, 11 November 1942, [[Bay of Biscay]]{{sfn|Colledge|Wardlow|2006|p=364}}
|-
| {{HMS|Undaunted|N55|6}} ||align="center"|4 September 1939 || Sunk 13 May 1941 off Libyan coast{{sfn|Colledge|Wardlow|2006|p=365}}
|-
| {{HMS|Union|N56|6}} ||align="center"|4 September 1939 || Sunk 20 July 1941 by Italian torpedo boat and aircraft near Panttellaria{{sfn|Colledge|Wardlow|2006|p=366}}
|-
| {{HMS|Unique|N95|6}} ||align="center"|4 September 1939 || Sunk 24 October 1942 west of Gibraltar{{sfn|Colledge|Wardlow|2006|p=366}}
|-
| {{HMS|Upholder|P37|6}} ||align="center"|4 September 1939 || Sunk 14 April 1942 by the Italian torpedo boat ''[[talian torpedo boat Pegaso (1936)|Pegaso]]'' off Tripoli{{sfn|Colledge|Wardlow|2006|p=366}}
|-
| {{HMS|Upright|N89|6}} ||align="center"|4 September 1939 || Sold 19 December 1945, broken up March 1946{{sfn|Colledge|Wardlow|2006|p=366}}
|-
| {{HMS|Urchin|N97|6}} ||align="center"|4 September 1939 || Loaned to the [[Polish Navy]] November 1941–1946 as {{ORP|Sokół|N97|6}}; named P97 in 1946, broken up 1949{{sfn|Colledge|Wardlow|2006|p=367}}
|-
| {{HMS|Urge|N17|6}} ||align="center"|4 September 1939 || Sunk 6 May 1942 by Italian torpedo boat ''Pegaso''{{sfn|Colledge|Wardlow|2006|p=367}}
|-
| {{HMS|Usk|N65|6}} ||align="center"|4 September 1939 || Sunk, thought mined, 3 May 1941 off Cap Bon, Tunisia{{sfn|Colledge|Wardlow|2006|p=367}}
|-
| {{HMS|Utmost|N19|6}} ||align="center"|4 September 1939 || Sunk 24 November 1942 by Italian torpedo boat ''[[Ciclone-class torpedo boat|Groppo]]'' west of Sicily{{sfn|Colledge|Wardlow|2006|p=367}}
|-
|}

== Group III boats ==

{|{{Infobox ship begin|sclass=2}}
{{Infobox ship image
|Ship image= File:Shadowgraph U british class groupe III submarine.svg
|Ship caption=Group three boats
}}
{{Infobox ship class overview
|Name='''Group three'''
|Builders=
|Operators=
|Class before=
|Class after=
|Subclasses=
|Cost=
|Built range=
|In service range=
|In commission range=
|Total ships building=
|Total ships planned=
|Total ships completed=34
|Total ships cancelled=
|Total ships active=
|Total ships laid up=
|Total ships lost=
|Total ships retired=
|Total ships preserved=
}}
{{Infobox ship characteristics
|Hide header=
|Header caption=
|Ship type=Submarine
|Ship displacement={{Unbulleted list| {{cvt|662|LT}} surfaced, {{cvt|740|LT}}
}}
|Ship length={{cvt|205|ft}}
|Ship beam={{cvt|16|ft}}
|Ship draught={{cvt|10|ft}}
|Ship power={{cvt|800|bhp}} engines, {{cvt|760|bhp}} motors
|Ship propulsion=
|Ship speed={{Unbulleted list| {{cvt|12.75|kn}} surfaced
| {{cvt|9|kn}} submerged
}}
|Ship range={{cvt|5000|mi}} at {{cvt|10|kn}}
|Ship endurance={{cvt|120|mi}} submerged
|Ship test depth={{cvt|300|ft}}
|Ship complement=37 (maximum)
|Ship sensors=
|Ship EW=
|Ship armament={{Unbulleted list|bow 4 × [[British 21 inch torpedo|21-inch (533 mm)]] [[torpedo tube]]s (8 × [[torpedo]]es)
|(later, 6 mines)
|1 × [[QF 12-pounder 12 cwt naval gun|QF 12-pounder]]
| 3 × machine-guns)
}}
|Ship armour=
|Ship notes=Data from McCartney, p. 17, ''British Submarines 1939–45'', 2006, Osprey Publishing, Oxford, {{isbn|978-1-84603-007-9}}
}}
|}
The third group formed the largest group of U-class submarines, comprising 34 vessels ordered in three batches. Losses continued to be high. In June 1940 the decision was taken, in view of the anticipated high number of submarines to be ordered, to drop the practice of naming submarines and the vessels were called ''P31'' to ''P39'', ''P41'' to ''P49''. At the end of 1942 Winston Churchill ordered that all submarines were to receive names but eight of the ''U''-class boats were lost before they could receive them, whilst on operations with the Royal Navy.{{sfn|McCartney|2006|pp=16–17}}
{{clear}}
===11 March 1940 batch===
{| class = "wikitable sortable"
|+ Group III boats [Data from Walters (2004), Colledge and Wardlow (2006)]
|-
!Name/<br>No.
!Ordered
! Notes
|-
| {{HMS|Ullswater|P31|6}} ||align="center"|11 March 1940 || Renamed ''Uproar'' April 1943, sold 13 February 1946, broken up{{sfn|Colledge|Wardlow|2006|p=364}}
|-
| {{HMS|P32|1940|6}} ||align="center"|11 March 1940 || Mined off Tripoli 18 August 1941 before named{{sfn|Colledge|Wardlow|2006|p=257}}
|-
| {{HMS|P33|1941|6}} ||align="center"|11 March 1940 || Presumed lost to a mine off Tripoli, 20 August 1941, before named{{sfn|Colledge|Wardlow|2006|p=257}}
|-
| {{HMS|Ultimatum|P34|6}} ||align="center"|11 March 1940 || Sold 23 December 1949 broken up{{sfn|Colledge|Wardlow|2006|p=364}}
|-
| {{HMS|Umbra|P35|6}} ||align="center"|11 March 1940 || Sold 9 July 1946, broken up{{sfn|Colledge|Wardlow|2006|p=364}}
|-
| {{HMS|P36|submarine|6}} ||align="center"|11 March 1940 || Delivered agents to France late 1941, transferred to Mediterranean, lost before naming{{sfn|Walters|2004|pp=189–190, 9}}
|-
| {{HMS|Unbending|P37|6}} ||align="center"|11 March 1940 || Sold 23 December 1949, broken up 1950{{sfn|Colledge|Wardlow|2006|p=364}}
|-
| {{HMS|P38|1941|6}} ||align="center"|11 March 1940 || Sunk by Italian ships ''Circe'' and ''Usodimare'' off Tunisia 25 February 1942 before named{{sfn|Colledge|Wardlow|2006|p=357}}
|-
| {{HMS|P39|1941|6}} ||align="center"|11 March 1940 || Sunk during air attack on Malta 26 March 1942 before named, raised June 1943, broken up 1954{{sfn|Colledge|Wardlow|2006|p=257}}
|-
| {{HMS|P41|submarine|6}} ||align="center"|11 March 1940 || Loaned to the [[Royal Norwegian Navy]] as {{HNoMS|Uredd|P41|6}}; lost with all 39 men to a mine after 5 February 1943.{{sfn|Walters|2004|p=197}}{{efn|The wreck was discovered near the north end of the {{lang|de|Flankensperre}} minefield in 1985. The field had been extended in mid-1942 unknown to the Admiralty.{{sfn|Walters|2004|p=198}}}}
|-
|}

===23 August 1940 batch===
{| class = "wikitable sortable"
|+ Group III boats [Data from Walters (2004), Colledge and Wardlow (2006)]
|-
!Name/<br>No.
!Ordered
! Notes
|-
| {{HMS|Unbroken|P42|6}} ||align="center"|23 August 1940 || Loaned to Soviet Navy 1944–1949 as ''V 2'', returned 9 May 1950, broken up{{sfn|Colledge|Wardlow|2006|p=365}}
|-
| {{HMS|Unison|P43|6}} ||align="center"|23 August 1940 || Loaned to Soviet Navy as ''V 3''
|-
| {{HMS|United|P44|6}} ||align="center"|23 August 1940 || Broken up 12 February 1946{{sfn|Colledge|Wardlow|2006|p=366}}
|-
| {{HMS|Unrivalled|P45|6}} ||align="center"|23 August 1940 || Arrived 22 January 1946 for breaking up{{sfn|Colledge|Wardlow|2006|p=366}}
|-
| {{HMS|Unruffled|P46|6}} ||align="center"|23 August 1940 || Broken up January 1946{{sfn|Colledge|Wardlow|2006|p=366}}
|-
| {{HMS|P47|submarine|6}} ||align="center"|23 August 1940 || Loaned to the [[Royal Netherlands Navy]] as {{HNLMS|Dolfijn|1942|6}}
|-
| {{HMS|P48|1942|6}} ||align="center"|23 August 1940 || Sunk in Gulf of Tunis by Italian ship ''Ardente'' 25 December 1942 before named{{sfn|Colledge|Wardlow|2006|p=357}}
|-
| {{HMS|Unruly|P49|6}} ||align="center"|23 August 1940 || Arrived February 1946 for breaking up{{sfn|Colledge|Wardlow|2006|p=366}}
|-
| {{HMS|Unseen|P51|6}} ||align="center"|23 August 1940 ||Arrived 11 May 1949 for breaking up{{sfn|Colledge|Wardlow|2006|p=366}}
|-
| {{HMS|P52|submarine|6}} ||align="center"|23 August 1940 || Loaned to the [[Polish Navy]] as {{ORP|Dzik|P52|6}} and post-war to the [[Royal Danish Navy]] as {{HDMS|U 1 Springeren|S321|6}}
|-
| {{HMS|Ultor|P53|6}} ||align="center"|23 August 1940 || Sold 22 January 1946, broken up{{sfn|Colledge|Wardlow|2006|p=364}}
|-
|{{HMS|Unshaken|P54|6}} ||align="center"|23 August 1940 || Broken up March 1946{{sfn|Colledge|Wardlow|2006|p=366}}
|-
|}

===12 July 1941 batch===
{| class = "wikitable sortable"
|+ Group III boats [Data from Walters (2004), Colledge and Wardlow (2006)]
|-
!Name/<br>No.
!Ordered
! Notes
|-
| {{HMS|Unsparing|P55|6}} ||align="center"|12 July 1941 || Sold 14 February 1946, broken up{{sfn|Colledge|Wardlow|2006|p=366}}
|-
| {{HMS|Usurper|P56|6}} ||align="center"|12 July 1941 || Sunk 4 October 1943 by German ship UJ2208 or by mine in the [[Gulf of Genoa]]{{sfn|Colledge|Wardlow|2006|p=367}}
|-
| {{HMS|Universal|P57|6}} ||align="center"|12 July 1941 || sold February 1946{{sfn|Colledge|Wardlow|2006|p=366}}
|-
| {{HMS|Untamed|P58|6}} ||align="center"|12 July 1941 || Foundered 30 May 1943, raised 5 July 1943, renamed HMS ''Vitality'', sold 13 February 1946, arrived March 1946 for breaking up{{sfn|Colledge|Wardlow|2006|p=366}}
|-
| {{HMS|Untiring|P59|6}} ||align="center"|12 July 1941 || Loaned July 1945 to 1953 to the [[Royal Hellenic Navy]] as {{HS|Xifias|Y10|6}}, sunk 25 July 1957 as an Asdic target{{sfn|Colledge|Wardlow|2006|p=366}}
|-
| {{HMS|Varangian|P61|6}} ||align="center"|12 July 1941 || sold June 1949, broken up{{sfn|Colledge|Wardlow|2006|p=369}}
|-
| {{HMS|Uther|P62|6}} ||align="center"|12 July 1941 || Sold February 1950, arrived 20 February 1950 for breaking up{{sfn|Colledge|Wardlow|2006|p=367}}
|-
| {{HMS|Unswerving|P63|6}} ||align="center"|12 July 1941 || Arrived 10 July 1949 for breaking up{{sfn|Colledge|Wardlow|2006|p=366}}
|-
| {{HMS|Vandal|P64|6}} ||align="center"|12 July 1941 || Wrecked 24 February 1943, [[Firth of Clyde]]{{sfn|Colledge|Wardlow|2006|p=369}}
|-
| {{HMS|Upstart|P65|6}} ||align="center"|12 July 1941 || Loaned post-war to the [[Royal Hellenic Navy]] as {{HS|Amphitriti|Y11|6}}
|-
| {{HMS|Varne I|P66|6}} ||align="center"|12 July 1941 || Loaned to the [[Royal Norwegian Navy]] as {{HNoMS|Ula|1943|6}}
|-
| {{HMS|Vortex|P87|6}} ||align="center"|12 July 1941 || Loaned post-war to the [[Royal Danish Navy]] as {{HDMS|U 3 Sælen|S323|6}}
|-
|  {{HMS|Vox I|P67|6}} ||align="center"|12 July 1941 || Loaned to the [[Free French Naval Forces]] as [[French submarine Curie (P67)|''Curie'']]
|-
| {{HMS|Vulpine|P79|6}} ||align="center"|12 July 1941 || Loaned post-war to the [[Royal Danish Navy]] as {{HDMS|U 2 Støren|S322|6}}
|-
|}

==V-Class submarine==
The V-class boats were the final refinement of the U-class submarines, 34 were ordered and 21 were built by Vickers for the War Emergency Programmes of 1941 and 1942, the rest being cancelled. The hull was further lengthened to try to eliminate the singing propellers and the bows were more streamlined. Welding of the hull frames was introduced to use thicker steel for the pressure hull, giving a diving depth of {{cvt|300|ft}}. None of the V-class boats were lost and some did not see service. The boats were named {{HMS|Upshot|P82|6}}, {{HMS|Urtica|P83|6}}, {{HMS|Vagabond|P18|6}}, {{HMS|Variance|P85|6}}, {{HMS|Venturer|P68|6}}, {{HMS|Vigorous|P74|6}}, {{HMS|Viking|P69|6}}, {{HMS|Vampire|P72|6}}, {{HMS|Varne II|P81|6}}, {{HMS|Veldt|P71|6}}, {{HMS|Vineyard|P84|6}}, {{HMS|Virtue|P75|6}}, {{HMS|Visigoth|P76|6}}, {{HMS|Vivid|P77|6}}, {{HMS|Voracious|P78|6}}, {{HMS|Votary|P29|6}}, {{HMS|Vox II|P73|6}}, {{HMS|Virulent|P95|6}}, {{HMS|Volatile|P96|6}}, {{HMS|Vortex|P87|6}} and {{HMS|Vulpine|P79|6}}.{{sfnm|1a1=Walters|1y=2004|1pp=12–14|2a1=McCartney|2y=2006|2p=17}}

== See also ==
* [[British V-class submarine]]
* [[List of submarines of France]]

==Notes==
{{notelist}}

== Footnotes ==
{{Reflist|20em}}

==References==
{{refbegin}}
* {{cite book |last=Brown |first=D. K. |title=Nelson to Vanguard |year=2012 |orig-year=2000 |publisher=Chatham Publishing |location=Barnsley |edition=hbk. repr. Seaforth Publishing (Pen & Sword) |isbn=978-1-84832-149-6}}
* {{cite book |last=Chesneau |first=Roger |editor-last=Gardiner |editor-first=Robert|title=Conway's All the World's Fighting Ships 1922–46 |year=1992 |orig-year=1980 |publisher=Conway Maritime Press |location=London |url=https://archive.org/details/conwaysallworlds1922unse/page/n7/mode/2up |url-access=registration |via=Archive Foundation |edition=3rd |isbn=978-0-85177-146-5}}
* {{cite book |last1=Colledge |first1=J. J. |last2=Wardlow |first2=B. |title=[[Ships of the Royal Navy]]: The Complete Record of all Fighting Ships of the Royal Navy |year=2006 |orig-year=1969 |publisher=Chatham |location=London |edition=2nd rev. |isbn=978-1-86176-281-8}}
* {{cite book |last=McCartney |first=I. |series=New Vanguard (No. 159) |title=British Submarines 1939–45 |year=2006 |publisher=Osprey |location=Oxford |isbn=978-1-84603-007-9}}
* {{cite magazine |last=van den Pol |first=E. |date=1989 |title=Aspects of submarines - Part I: Some notes on development|magazine=Schip en Werf|location=Rotterdam |publisher=Wyt & Zonen |volume=56|issue=10|issn= 0036-6099|pages=352-358}}
* {{cite web |url=http://uboat.net/allies/warships/class.html?ID=50 |title=U class |work=uboat.net}}
* {{cite web |url=http://home.cogeco.ca/~gchalcraft/sm/page29.html |title=Untiring to Urge |work=British submarines of World War II |url-status=dead |archive-url=https://web.archive.org/web/20070711194518/http://home.cogeco.ca/~gchalcraft/sm/page29.html |archive-date=11 July 2007}}
* {{cite book |last=Walters |first=Derek |title=The History of the British 'U' Class Submarine |year=2004 |publisher=Pen & Sword |location=Barnsley |isbn=978-1-84415-131-8}}
{{refend}}

==Further reading==
* {{cite book |last=Friedman |first=N. |title=British Submarines in two World Wars |year=2019 |orig-year= |publisher=Seaforth (Pen & Sword) |location=Barnsley |edition=e-Pub |isbn=978-15267-3817-2}}
* {{cite book |last=Hutchinson |first=Robert |title=Submarines, War Beneath The Waves, From 1776 To The Present Day |year=2001 |publisher=HarperCollins |location=London |isbn=978-0-00-710558-8}}

== External links ==
{{Commons category|British U class submarine}}
* [http://rnsubs.co.uk/boats/subs/u-class.html RN Submarines 1936–1958: U Class]

{{British U class submarine}}
{{WWII British ships}}
{{WWII Soviet ships}}
{{Authority control}}

[[Category:British U-class submarines| ]]
[[Category:Submarine classes]]