"U" class Coastal Submarines
Individual Specifications
Name Pennant Builder Completed Fate
Group 1
Undine * 48C Vickers 21/8/38 Depth-charged by German Minesweepers M.1201, M.1204 & M.107 off
Heligoland, scuttled, 7/1/40
Unity 66C Vickers 5/10/38 Colided with mercantile Atle Jarl off Blyth, 29/4/40
Ursula 59C Vickers 20/12/38 To Soviet Union as B.4, 1944. Returned 1949 & scrapped
Group 2
Umpire 82N Chatham RDY 10/7/41 Rammed in error by trawler Peter Hendriks off The Wash, 19/7/41
Una 87N Chatham RDY 27/9/41 Scrapped 1949
Unbeaten 93N Vickers 10/11/40 Bombed in error by RAF in Bay of Biscay, 11/11/42
Undaunted 35N Vickers 30/12/40 Probably mined off Tripoli, c. 7/5/41
Union 56N Vickers 22/2/41 Depth-charged by Italian motor boat Circe off Pantellaria, 20/7/41
Unique 95N Vickers 27/9/40 Loss unexplained off Gibralter, c. 10/10/42
Upholder 99N Vickers 31/10/40 Depth-charged by Italian motor boat Pegaso off Tripoli, 14/4/42
Upright 89N Vickers 3/9/40 Scrapped 1945
Urchin 97N Vickers 28/1/41 To Poland as Sokol, 1942. Returned 1946 & scrapped 1949
Urge 17N Vickers 12/12/40 Bombed by Italy in Eastern Mediterannean, 29/4/42
Usk 65N Vickers 11/10/40 Probably mined off Cape Bon, c. 26/4/41
Utmost 19N Vickers 17/8/40 Depth-charged by Italian motor boat Groppo off Marittimo, 25/11/42
Group 3
Uproar ex-
P31 Vickers 2/4/41 Scrapped 1946
P32 P32 Vickers 3/5/41 Mined off Tripoli, 18/8/41
P33 P33 Vickers 30/5/41 Probably mined off Tripoli, 15/8/41
Ultimatum P34 Vickers 29/7/41 Scrapped 1950
Umbra P35 Vickers 2/9/41 Scrapped 1946
P36 P36 Vickers 24/9/41 Bombed by Luftwaffeoff Sliema, 1/4/42. Salved 8/7/58 & scrapped
Unbending P37 Vickers 5/11/41 Scrapped 1952
P38 P38 Vickers 17/10/41 Depth-charged by Italian motor boat Circe off Ras Misurata, 23/2/42
P39 P39 Vickers 16/11/41 Bombed by Luftwaffe in Valetta, 26/3/42, written off. Salvaged then bombed
in Kalkara creek, ?/6/43, scrapped 1954.
Uredd P41 Vickers 12/12/41 Royal Norwegian Navy, mined off Bodø, 10/2/43
Unbroken P42 Vickers 29/1/42 To Soviet Union as B.2, 1944. Returned 1949 & scrapped 1950
Unison P43 Vickers 19/2/42 To Soviet Union as B.3, 1944. Returned 1949 & scrapped 1950
United P44 Vickers 2/4/42 Scrapped 1946
Unrivalled P45 Vickers 3/5/42 Scrapped 1946
Unruffled P46 Vickers 9/4/42 Scrapped 1946
Dolfijn P47 Vickers 8/10/42 Royal Netherlands Navy, scaspped 1952
P48 P48 Vickers 18/6/42 Depth-charged by Italian corvette Ardente off Zembra Island, 25/12/42
Unruly P49 Vickers 3/11/42 Scrapped 1946
Unseen P51 Vickers 2/7/42 Scrapped 1949
Dzik P52 Vickers 16/12/41 Polish Navy. To Denmark 1946 as U.1, then Springeren 1948-. Returned
1957 & scrapped.
Ultor P53 Vickers 31/12/42 Scrapped 1946
Unkshaken P54 Vickers 21/5/42 Scrapped 1946
Unsparing P55 Vickers 29/11/42 Scrapped 1946
Usurper P56 Vickers 2/2/43 Depth-charged by German trawler Uj.2208 in Gulf of Genoa, c. 11/10/43
Universal P57 Vickers 8/3/43 Scrapped 1946
Untamed P58 Vickers 14/4/43 Lost in diving accident off Cambletown, 30/5/43. Salved 5/7/43 and renamed
Vitality, scrapped 1946
Untiring P59 Vickers 9/6/43 To Greece as Xifias, 1945. Returned 1952 & expended as target off Start
Point, 25/7/57
Varangian P61 Vickers 10/7/43 Scrapped 1949
Uther P62 Vickers 15/8/43 Scrapped 1950
Unswerving P63 Vickers 3/10/43 Scrapped 1949
Vandal P64 Vickers 20/2/43 Wrecked in Kilbrennan Sound, 24/2/43
Upstart P65 Vickers 3/4/43 To Greece as Amfrititi, 1945. Returned 1952 & expended as target off Isle of
Wight, 25/7/57
Varne P66 Vickers 3/4/43 To Norway as Ula, 1943. Scrapped 1966
Vox P67 Vickers 2/5/43 To France as Curie 1943. Returned 1946 & scrapped 1949.

* = Armament & Displacement variation, see tables

1:600 HM s/m Undine, "U" class group 1. The lack of a deck
gun and the bulbous nose housing the external torpedoes are
visible here. This casing was found ( like in the "T" class ) to
impair vision at periscope depth and was only found on 7 "U"
class of all groups. © Andrew Arthur
1:600 HM s/m Ursula, "U" class group 1. She was the only member
of the first goroup to have a deck gun, a 12pdr. AA gun.
Unfortunately, there was no hatch to serve this weapon, and it was
a race against time to get all crew up the conning tower and into
that hatch during a crash dive! © Andrew Arthur
1:600 HM s/m Upholder, one of four "U" class group 2 submarines
to retain the bulbous bow & torpedoes. The deck gun was a 12pdr.
AA, but this group did have a deck-gun hatch.© Andrew Arthur
1:600 HMS s/m Una, of the main batch of "U" class group 2. The
external tubes were removed and replaced with a fined off, raked
casing forwards.© Andrew Arthur
1:600 "U" class group 3. The casing was fined off at the end, to
allow for quieter, more efficient steaming. The gun was a 3"
low-angle type. © Andrew Arthur

This class was originally designed as an unarmed "H" class replacement, for training both submarine crews and escort teams, but early in their development it was decided to arm them to make them capable of short war patrols.
As such, the first group of three units was armed with four internal and two external 21" torpedo tubes. The external tubes were in a bulbous casing like the early "T" class, and the same problems as the latter stemmed from this : at periscope depth, the casing created a large wake, and this obscured periscope view forward. In addition, Undine fitted a 12pdr AA gun in-front of the conning tower. The only problem with this was that there was no special gun hatch, and it was with a great struggle that the gun crew and ammunition got out the conning tower hatch in a rush, that the gun was supplied with ammunition with a full bridge watch, and that in a crash dive, both the birdge & gun crews and all the ammnition got back down the hatch in a hurry!
Single hulled construction was opted for, all ballast and fuel being carried internally, and a casing covered the fore ends of the full for about 3/4 of it's length, tailing off after the conning tower.
To simplify ( and compact ) machinery arrangements, they adopted diesel-electric surface drive; the diesels were permamnently connected to the generators, and for surface power, the motors were run straight from the generators. This meant no bulky, complex and hard to produce gearing & reversing arrangements were needed, and particualarly in war, gearing jigs took a long time to manufacture and get into production.
At the out-break of WW2 the three first class units were put into action, and were extremely successful in the shallow confines of the Mediterranean, Norwegian Fjords and the coastal waters of the UK.
Because of their success, they were put right back into production, and the second group differed mainly in having a permamnent deck-gun and gun hatch, and after the first four units, no bow tubes, and a fined, raked casing forwards. Also, uprated diesels and generators were fittted, and propulsion was quietened and made more efficient by adopting finer, better machined propellors. The third group had a slightly lengthened after casing for smoother surface running.
As already mentioned, they were very succesful. Being very simple to manufacture ( compared with German and Italian  submarines, they were very dated ), a real bonus in wartime and easy to train crews for ( particualarly those of the Free French, Greek, Norwegian & Netherlands navies, and the Soviet Union ). Aslo, being around in large numbers, they could absorb a disproportionate amount of the enemy's ASW resources.
It was the inshore waters of the UK & Norway and the confines of the Mediterannean that was their hunting grounds, always being fairly close to home ( never more than two days sailing from base ), their small size allowed them to work close inshore undetected, and although they were not very significant themselves, as a cxlass they were..
Being small however, conditions aboard were far from comfortable, one veteran describing a term in  naval detention barracks a holiday compared with the forends of a "U" class submarine.
After the war in Europe ended they were quickly relegated back to training, and soon paid off and scrapped, or passed onto other Navies.

  Group 1 Group 2 Group 3   Group 1 Group 2 Group 3
Empty Displacement 540 tons 545 tons 540 tons Length 191' 192.25' 196.75'
Surfaced Displacement 578 tons (*=594) 586 tons 581 tons Beam 16' 16' 16'
Submerged Displacement 730 tons 735 tons 730 tons Draft 12.75-14.5' 12.75-14.5' 12.75-14.5'
Performance & Propulsion
Group 1 Group 2 Group 3
3800 nm @ 10 kts = 37 days
11.75 kts ( 10 kts submerged ) 12 kts ( 9 kts submerged )
2 x 6cyl. Paxman-Ricardo diesels @ 615 bhp,
2 x generators @ 450 kW,
2 x GEC electric motors @ 825 shp
2 x 8cyl. Paxman-Ricardo diesels @ 800 bhp,
2 x generators @ 600 kW,
2 x GEC electric motors @ 825 shp
Armament & Complement
Group 1 Group 2 Group 3
5 officers & 22 ratings (* = 6 + 27 ) 6 officers & 25 ratings
  • Torpedo
    • 4 x 21" bow tubes ( internal )
    • 2 x 21" bow tubes ( external )
    • 10 x 21" torpedoes
  • Gun
    • 1 x 1 x 12pdr. AA ( in * only )
    • 2 x 1 x 0.303" MG AA
  • Torpedo
    • 4 x 21" bow tubes
    • 8 x 21" torpedoes
  • Gun
    • 1 x 1 x 12pdr. AA
    • 3 x 1 x 0.303" MG AA
  • Torpedo
    • 4 x 21" bow tubes
    • 8 x 21" torpedoes
  • Gun
    • 1 x 1 x 3" USN pattern
    • 3 x 1 x 0.303" MG AA
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