HNLMS O 23

{{Short description|O 21-class submarine of the Royal Netherlands Navy}}

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|Ship image=Onderzeeboot 023, Bestanddeelnr 902-4321.jpg

|Ship caption=O 23

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|Ship country=Netherlands

|Ship flag={{shipboxflag|Netherlands|naval}}

|Ship name=O 23

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|Ship builder=Rotterdamsche Droogdok Maatschappij, Rotterdam

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|Ship yard number=RDM-205{{cite web |author= |title=Bouwnummer RDM-205, Hr. Ms. “O 23”, 1940, onderzeeboot. |url=https://www.rdm-archief.nl/project/bouwnummer-rdm-205-hr-ms-o-23-1940-onderzeeboot/|website=RDM-archief |language=Dutch}}

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|Ship laid down=12 October 1937

|Ship launched=5 December 1939

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|Ship commissioned=13 May 1940

|Ship decommissioned=1 December 1948

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|Ship fate=Sold for scrap, April 1949

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{{Infobox ship characteristics

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|Ship class= {{sclass|O 21|submarine}}

|Ship displacement=*{{cvt|987|LT|t|lk=on}} (surfaced)

{{cvt|1488|LT|t}} (submerged)

|Ship length= {{cvt|255|ft|m|1}}

|Ship beam={{cvt|21|ft|6|in|m|1}}

|Ship draft={{cvt|13|ft|m|1}}}

|Ship power=

|Ship propulsion=*2 × {{cvt|2500|bhp|0|lk=on}} diesel engines

2 × {{convert|500|bhp|0|abbr=on}} electric motors

|Ship speed=*{{convert|19.5|kn|lk=in}} (surfaced)

{{convert|9|kn|abbr=on}} (submerged)

|Ship range=*{{convert|10000|nmi|abbr=on|lk=in}} at {{convert|11|kn}} (surfaced)

{{cvt|28|nmi}} at {{convert|9|kn|abbr=on}} (submerged)

|Ship test depth={{cvt|330|ft|m}}

|Ship complement=60

|Ship armament=*4 × {{cvt|21|in|0}} bow torpedo tubes

2 × {{cvt|21|in|0}} stern torpedo tubes
2 × {{cvt|21|in|0}} external traversing torpedo tubes
2 × single Bofors 40 mm L/60 gun AA guns

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O 22 was a {{sclass|O 21|submarine}} built for the Royal Netherlands Navy during the 1930s for European service. Completed in 1940, she sank several ships during World War II in the Mediterranean and in the Indian Ocean.

Design and description

The O 21-class submarines were slightly smaller versions of the preceding {{sclass|O 19|submarine|4}} since they lacked that class's minelaying capability. The boats had a length of {{convert|255|ft|m|1}} overall, a beam of {{convert|21|ft|6|in|m|1}} and a draft of {{convert|13|ft|m|1}}.Bagnasco, p. 240 They displaced {{convert|987|LT|t}} on the surface and {{convert|1488|LT|t}} submerged. The submarines had a crew of 60 officers and enlisted men.van Willigenburg, p. 69

For surface running, the boats were powered by two {{convert|2500|bhp|lk=in|0|adj=on}} Sulzer diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a {{convert|500|hp|0|adj=on}} electric motor. They could reach {{convert|19.5|kn|lk=in}} on the surface and {{convert|9|kn}} underwater. On the surface, the boats had a range of {{convert|10000|nmi|lk=in}} at {{convert|12|kn}} and {{convert|28|nmi|abbr=on}} at 9 knots submerged. The submarines had a diving depth of {{convert|330|ft|m}}.

The O 21 class was armed with eight {{convert|21|in|mm|adj=on|sp=us|0}} torpedo tubes. Four of these were in the bow and two tubes were in the stern. The other pair were on a external rotating mount amidships. A reload was provided for each internal torpedo tube. They were also armed with two Bofors 40 mm L/60 gun AA guns; these were on single watertight mounts that retracted into the conning tower when submerged.Bagnasco, p. 238

Construction and career

File:Onderzeeboot Hr.Ms. O 23 (1940-1949) in baai van Gibraltar (2158 015511).jpg

O 23 was ordered on 19 June 1937 and laid down on 12 October 1937 at the shipyard of Rotterdamsche Droogdok Maatschappij in Rotterdam. The boat was launched on 5 December 1939. Following the German invasion of 10 May 1940, O 23 was hastily commissioned, still incomplete, and sailed for England on 13 May, together with her sister {{HNLMS|O 24||2}}, to be completed at the Thornycroft shipyard at Southampton.

During the war she operated in the North Sea, the Mediterranean Sea and the Indian Ocean. O 23 made twenty patrols during the war in the course of which she sank or damaged five ships. She survived the war and was decommissioned on 1 December 1948, being sold for scrap in April of the following year.{{cite web |url= http://uboat.net/allies/warships/ship/2894.html|title=HNMS O 23 |first=Guðmundur |last=Helgason |work=uboat.net |year=2013 |accessdate=24 June 2025}}

Summary of raiding history

Ships sunk and damaged by O 23.

Date \|\| Ship name \|\| Nationality/Type \|\| Tonnage (GRT) \|\| Fate
class="wikitable"
30 June 1941	Capacitas	Italian tanker	5371	Sunk
27 July 1942	Shofuku Maru No.2	Japanese merchant ship	729	Damaged
2 August 1942	Zenyo Maru	Japanese army cargo ship	6440	Damaged (burned out and later declared a total loss)
2 August 1942	Ohio Maru	Japanese transport ship	5872	Sunk
25 October 1942	Shinyu Maru	Japanese merchant ship	4622	Damaged

References

Bibliography

{{cite book |last1=Bagnasco |first1=Erminio |title=Submarines of World War Two: Design, Development and Operations |date=2018 |publisher=Naval Institute Press |isbn=978-1-68247-384-9|orig-year=1977}}
{{cite book |last=Lenton |first=H.T. |date=1968 |title=Royal Netherlands Navy |publisher=Macdonald & Co. |series=Navies of the Second World War |isbn=|author-link=Henry Trevor Lenton}}
{{cite book |last=Mark |first=Chris |date=1997 |title=Schepen van de Koninklijke Marine in W.O. II |language=Dutch|edition= |url= |location=Alkmaar |publisher=De Alk |page= |isbn=90-6013-522-9}}
{{cite book |last1=Noppen |first1=Ryan K. |title=The Royal Netherlands Navy of World War II |date=2020 |publisher=Osprey Publishing |isbn=978-1-4728-4191-9|series=New Vanguard|volume=285}}
{{cite book |last=van Willigenburg |first=Henk |date=2010 |title=Dutch Warships of World War II |publisher=Lanasta |isbn=978-90-8616-318-2}}