Jolly Roger Class
O 21
Boats in this Class
O 21, O 22, O 23
O 24, O 25, O 26, O 27

 

O 23,  31 Jan 1947 O 23,  31 Jan 1947

For additional photos and information please check the 'related pages list' at the bottom of this page.

 

Boat O 21 O 22 O 23 O 24 O 25 O 26 O 27
Pennant # S801,
O 21,
P 21,
K XXI
O 22,
P 22,
K XXII
O 23,
P 23,
K XXIII
A 875 1958,
S804,
O 24,
P 24,
K XXIV
O 25,
U D3,
K XXV
O 26,
U D4,
K XXVI
S807,
O 27,
U D5,
K XXVII
Yard # 207 208 205 206 667 ? 674 209 210
Type Patrol submarine
Class name O 19. Named after first of class, 'O' stands for 'Onderzeeboot' (submarine)
Ordered ? 12/4/37 9/6/37 21/6/37 28/6/38 24/6/38 8/7/38
Laid down 20/11/37 20/11/37 12/10/37 12/11/37 10/4/39 20/4/39 3/8/39
Launched 21/10/39 20/1/40 5/12/39 18/3/40 1/5/40 23/11/40 ?26/4/41
?26/9/41
Comm. 10/5/40
uncompleted
10/5/40
uncompleted
13/5/40
uncompleted
13/5/40
uncompleted
German: 8/6/41 German: 28/1/41 German: 30/1/42
Dutch: 13/7/45
Decommissioned 2/11/57 8/11/40 1/12/48 22/2/54 German:
13/10/44
German
scuttled:
3/5/45
German
scuttled:
3/5/45
German
surrender:
May. 1945
Dutch:
14/11/59
Fate 24 Jan 1958 Sold for scrap Nov 1940 Mined Apr 1949 Sold for scrap Jun 1963
Broken up
3 May 1945 Scuttled Broken up 1961 Broken up
Other
names
Dutch:
K XXI
Dutch:
K XXII
Dutch:
K XXIII
Dutch:
K XXIV
Dutch:
K XXV
German:
U-D3
Dutch:
K XXVI
German:
U-D4
Dutch:
K XXVII
German:
U-D5
Design Dutch
Shipyard K.M. De Schelde,
Vlissingen
R.D.M, Rotterdam.
Completed by John
Thornycroft
Jun-
Jul 1940
Wilton
Fijenoord
,
Schiedam
R.D.M, Rotterdam
LexBexDr 77.7 m x 6.8 m x 3.95 m
Displacement Stnd/Surf/Subm 902 t / 990 t / 1205 t
Engines Two 7-cylinder Sulzer reversible diesel engines, 2-stroke,  2 x 2500 apk
Main motor 2 x 500 apk
Batteries 2 x 96 cells of each +/- 550 kg. 5350 Ah during 5 hours
Snorkel Yes.
O 21 and O 22 had their snort systems removed in May 1940. The Royal Navy found the system unnecessary and dangerous.
Propellers 2
Speed s/d 19.5 kts / 9 kts
Range surf/subm 10000 nm at 12 kts / 28 nm at 8.5 kts
Diving depth 100 m, crush depth 175 m.
Complement 39
Torp. tubes 4 x 21" bow, 2 x 21" stern, 2 x 21" (1x2) external-traversing amidships.
After WWII two torpedo tubes (presumably the deck tubes) were removed
Torpedo type General: When built V53? later Mark IV**?
O 21: Mk8, 1942 G 7AD, Mark IV**, Mark IV*SD,  Mk X
O 22: IV53 , Mk X
O 23: Mk8, Mk Xxx,1942 G 7A*D , Mark IV*SD
O 24: Mk8, Mark IV, 1942 G 7A*D, Mark IV*SD
O 25: IV53 
O 26: IV53 
O 27: Mk8 
Armament 14 torpedoes, incl. 6 reloads.
Guns - 1 x 8.8 cm / 45 AA Bofors mark 3, weight shell 22,  2625 ft/sec initial velocity.
- 2 x 40 mm (2x1) Vickers in single 'disappearing' mounts, in watertight wells forward and aft of the conning tower.
-  1 x 12.7 mm (probably Browning). 
- Since I have never seen a photo or drawing that displays the second 40mm (the only one imho is at the aft conning tower deck) the report of 2 x 40mm is probably incorrect. This theory is supported by a source that lists 2 x 40mm (1x2) was planned for O 24, but not delivered/installed. One 20 mm was installed instead.
-At a later date (sometime after WWII?) the arrangement was changed to 1 x 8.8 cm, 1 x 20 mm. Fate of the 1 x 12.7 mm is unknown. At a later date the 8.8 cm deck-gun was also removed, this to improve the streamline of the boat.
O 21: Also Lewis double (1x2), possibly 7.7 mm. All guns (incl. 1 x 20 mm) removed in the 1950s.
O 22: 1 x 8.8 cm, 1 x 20 mm,  possibly 1 x 12.7 mm
O 24 Early 1942 the 40 mm Vickers replaced by 20 mm Oerlikon. But an other source lists that originally 2 x 40mm (1x2) was planned for O 24, but not delivered/installed. One 20 mm was installed instead.
O 25,26,27: While in German hands these boats were fitted with 2 x 20 mm AA (2 x double according to some sources) in place of their intended 40 mm.
O 27: According to other sources O 27 was later during the war fitted with 2 x 20 mm and a 3,7 cm.
Her deck gun is currently displayed (unconfirmed) at the Military Home KTOMM Bronbeek
Periscopes Nedinsco ? ? ? ? ? ?
Sonar Equipped with a geruispeiler (listening device) from Atlas Werke (Bremen).
In those days 'Atlas' was the best on the market.
Notes - In 1940, only the first 4 boats of this class were seaworthy enough to flee to the U.K.
  The Germans captured the other boats.
- O 26, O 27 and possibly O 25 were also fitted with German type conning towers.
- Hull made of high tensile 52 steel.
- Class had de-centralized kingstons that reduced the filling time of the ballast tanks,
  and therefore reducing the time needed to dive.
- U-D3 and U-D5 were to be converted in torpedo transport, in order to support the German U-Boats
   operating off the US coast. It is not sure whether this conversion actually took place.
- Some sources report U-D3 was converted into a torpedo transport as well. But others report she was
   converted to a refuelling U-Boat used for submerged refuelling exercises.
- U-D4 is converted into a supply uboat.

 

 

O 21 class related pages
O 21 class specifications
O 21 class photos
   
O 21 class books
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