NAVYPEDIA

Photo

O25 Many thanks to Wolfgang Stöhr for additional information on this page.

Ships

Name	No	Yard No	Builder	Laid down	Launched	Comp	Fate
O21 (ex-K XXI)	S801	207	De Schelde, Vlissingen	11.1937	21.10.1939	5.1940	stricken 11.1957
O22 (ex-K XXII)		208	De Schelde, Vlissingen	11.1937	20.1.1940	5.1940	sunk 8?.11.1940
O23 (ex-K XXIII)		205	Rotterdamse Droogdok Mij, Rotterdam // Thornycroft, Southampton, UK	10.1937	5.12.1939	6.1940	stricken 12.1948
O24 (ex-K XXIV)	S804	206	Rotterdamse Droogdok Mij, Rotterdam // Thornycroft, Southampton, UK	11.1937	18.3.1940	7.1940	stricken 2.1954
O25 (ex-K XXV)		663	Wilton-Fijenoord, Schiedam	4.1939	1.5.1940	6.1941 // ---	captured incomplete by Germany 5.1940 (UD3)
O26 (ex-K XXVI)		209	Rotterdamse Droogdok Mij, Rotterdam	4.1939	23.11.1940	1.1941 // ---	captured incomplete by Germany 5.1940 (UD4)
O27 (ex-K XXVII)	S807	210	Rotterdamse Droogdok Mij, Rotterdam	8.1939	26.9.1941	1.1942 // 7.1945	captured incomplete by Germany 5.1940 (UD5), returned 5.1945, stricken 11.1959

Technical data

Displacement standard, t	902
Displacement normal, t	990 / 1205
Length, m	77.7
Breadth, m	6.80
Draught, m	3.95
No of shafts	2
Machinery	2 Sulzer 7-cyl diesels / 2 electric motors
Power, h. p.	5000 / 1000
Max speed, kts	19.5 / 9
Fuel, t	diesel oil
Endurance, nm(kts)	10000(12) / 28(8.5)
Armament	O21-23: 1 x 1 - 88/42 Bofors No.3, 1 x 1 - 40/36 Bofors, 1 x 1 - 12.7/90, 8 - 533 TT (4 bow, 2 stern, 1 x 2, 14) O24: 1 x 1 - 88/42 Bofors No.2, 1 x 1 - 20/70 Oerlikon, 1 x 1 - 12.7/90, 8 - 533 TT (4 bow, 2 stern, 1 x 2, 14) O27 (1945): 1 x 1 - 37/69 Flak M/42, 2 x 2 - 20/65 C/38, 6 - 533 TT (4 bow, 2 stern, 12)
Electronic equipment	O21-24: Atlas-built sonar O27 (presumably): FuMO 30 or FuMO 61 radar, GHG hydrophone, FuMB 3 Bali, FuMB 6 Palau ECM suites
Complement	39
Diving depth operational, m	100

Standard scale images

Graphics

Project history

Ordered as K XXI-XXVII, however "K" letters have been changed on "O" even prior to the beginning of building. Practically repeated O19 class, but without minelaying equipment. Double-hulled, maximal diving depth was 175m. They were equipped by 7cyl Sulzer diesels with snorkel. Thanks to the improved hull form and increase in machinery power max speed has grown. On these submarines they have refused centralized operation by ballast tank valves for diving time reduction.

In May, 1940 yet incomplete O21-24 were formally commissioned and escaped to Britain where have been completed, thus snorkel was removed.

Incomplete O25-27 in May, 1940 were captured by Germans and as UD3-5 were completed for Kriegsmarine under modified design. UD3 and UD4 were stricken and scuttled at Kiel 3.5.1945, subsequently they were salvaged and scrapped. UD5 was returned to the Netherlands in 1945.

Modernizations

1942, O21, 23: - 1 x 1 - 40/36, Atlas-built sonar; + 1 x 1 - 20/70 Oerlikon Mk II/IV, type 291W radar, type 129, type 138 sonars (presumably)

early 1950s, all survived: all guns were removed.

Naval service

O22 was lost on a mine in the North Sea in the period 7 till 19.11.1940.



Many thanks to Wolfgang Stöhr for additional information on this page.