View source for Type XXIII submarine

{{short description|German coastal submarine class}}
{{More footnotes needed|date=September 2021}}
{|{{Infobox ship begin}}
{{Infobox ship image
| Ship image = Tipo XXIII.svg
| Ship caption = Rendering of a Type XXIII submarine
}}
{{Infobox ship class overview
| Builders = *[[Deutsche Werft]], [[Hamburg]] (48 boats)
*[[Germaniawerft]], [[Kiel]] (13 boats)
| Operators = *{{navy|Nazi Germany|name=''Kriegsmarine''}}
*{{navy|West Germany}}
*{{navy|East Germany}}
*{{navy|United Kingdom}}
*{{navy|France}}
*{{navy|Soviet Union}}
*{{navy|Norway}}
| Class before = *[[Type II submarine]] (Conventional coastal submarine)
*[[Type XVII submarine]] (AIP-powered coastal submarine)
| Class after = [[Type 201 submarine|Type 201 coastal submarine]]
| Subclasses = 
| Built range = 1944&ndash;1945
| In commission range = 1944&ndash;1968
| Total ships building = 
| Total ships planned = 980 <ref name="Trevor Lenton 1965">Trevor Lenton, ''German Submarines 2'' (1965) in the Macdonald & Co series ''Navies of the Second World War''.</ref>
| Total ships completed = 61
| Total ships cancelled = 
| Total ships active = 
| Total ships laid up = 
| Total ships lost = 7
| Total ships retired = 
| Total ships preserved = 
}}
{{Infobox ship characteristics
| Hide header = 
| Header caption = 
| Ship displacement = *{{Convert|234|t|ST|abbr=on|lk=on}}  surfaced 
*{{Convert|258|t|ST|abbr=on}} submerged
| Ship length = {{Convert|34.68|m|ftin|frac=2|abbr=on}}
| Ship beam = {{Convert|3.02|m|ftin|frac=2|abbr=on}}
| Ship draft = {{Convert|3.66|m|ftin|frac=2|abbr=on}}
| Ship propulsion = *1 × [[MWM GmbH|MWM]] RS134S 6-cylinder diesel engine, {{convert|575|-|630|PS|kW shp}}
*1 × [[AEG (German company)|AEG]] GU4463-8 [[Motor-generator|double-acting electric motor]], {{convert|580|PS|kW shp|0}} 
*1 × [[Brown, Boveri & Cie|BBC]] CCR188 electric creeping motor, {{convert|35|PS|kW shp}}
| Ship speed = *{{convert|9.7|kn|km/h|abbr=on}} surfaced
*{{convert|12.5|kn|km/h|0|abbr=on}} submerged
| Ship range = *{{convert|2,600|nmi|km|-2|abbr=on}} at {{Convert|8|kn|km/h|0|abbr=on}} surfaced 
*{{Convert|194|nmi|km|0|abbr=on}} at {{Convert|4|kn|km/h|0|abbr=on}} submerged
| Ship test depth = {{Convert|180|m|ft|abbr=on}}
| Ship complement = 14–18
| Ship sensors = 
| Ship EW = 
| Ship armament = *2 bow [[torpedo tubes]]
*No reloads
| Ship notes = 
| Ship type = [[Coastal submarine]]
}}
|}

German '''Type XXIII submarines''' were the first so-called [[elektroboot]]e ("electric boats") to become operational. They were small [[coastal submarine]]s designed to operate in the shallow waters of the [[North Sea]], [[Black Sea]] and [[Mediterranean Sea]], where larger [[Type XXI submarine|Type XXI electric boats]] were at risk in [[World War II]]. They were so small they could carry only two [[torpedo]]es, which had to be loaded externally. As with their far larger sisters—the Type XXI—they were able to remain submerged almost all of the time and were faster than conventional U-boats, due to the improved streamlining of their shape, batteries with larger capacity and the [[submarine snorkel|snorkel]], which allowed the diesel engines to be used while submerged. The Type XXI and XXIII U-boats revolutionized post-war submarine design. Nearly a thousand Type XXIII boats were projected towards the close of World War II, but most of these were either cancelled, scrapped incomplete, or only projected.<ref name="Trevor Lenton 1965" />

==Background==
When development began on the Type XXI U-boat in late 1942, it was proposed to simultaneously develop a smaller version incorporating the same advanced technology to replace the [[Type II submarine|Type II]] coastal submarine. [[Karl Dönitz|Admiral Karl Dönitz]] added two requirements: as the boat would have to operate in the [[Mediterranean]] and the [[Black Sea]], it had to be able to be transported by rail, and it had to use the standard {{convert|53.3|cm|in|frac=8|abbr=on}} torpedo tubes.

The development of the Type XXIII was given a high priority, with an emphasis on using existing components as much as possible. To reduce development time, [[Hellmuth Walter]] designed the new submarine based on the previous [[Uncompleted U-boat projects|Type XXII]] prototype. By 30 June 1943 the design was ready and construction began in parallel at several shipyards in Germany, France, Italy and  Ukraine. The lead contractor was [[Deutsche Werft]] in [[Hamburg]].

As with the Type XXI, the Type XXIII was intended to be constructed in sections, various modules being produced by different subcontractors. Some were to be assembled at foreign yards, including ''U-2446'' through ''U-2460'' at the Deutsche Werft yard at [[Mykolaiv|Nikolaev]], Southern Ukraine. These were reassigned to the [[Linzner]] yard on 1 May 1944 and subsequently cancelled.<ref name=polmar322>Polmar, p. 322</ref> In the end, circumstances meant that construction was concentrated at [[Germaniawerft]] in [[Kiel]] and [[Deutsche Werft]] in [[Hamburg]], Germaniawerft building 51 and Deutsche Werft 49. Of the 280 submarines ordered, only 61 entered service, and only 6 ever carried out a war patrol.

==Description==
The Type XXIII had an all-welded single hull, the first submarine to use such a design. It had a fully streamlined outer casing and apart from the relatively small conning tower and a fairing which housed the diesel exhaust silencer, it had an uncluttered upper deck. In line with Walter's design practice, there were no forward [[planing (sailing)|hydroplane]]s, although these were added later.

The submarine was propelled by a single three-bladed propeller and steered by a single rudder. As with the Type XXI, the lower section of the figure-of-eight hull was used to house a large 62-cell battery.<ref name="Rössler209210">Rössler (2001), pp. 209-210.</ref>

In order to allow the boat to be transported by rail, the hull sections had to be limited in size to fit the standard [[loading gauge]]. For transportation, the hull was broken into four sections and the bridge was removed. Due to the space restrictions, the forward bow section had to be made as short as possible, which meant that only two torpedo tubes could be fitted and no reload torpedoes could be carried. The torpedoes were loaded by ballasting the submarine down at the stern so that the bow lifted clear of the water and the torpedoes could be loaded directly into their tubes from a barge.{{sfn|Williamson|Palmer|2002|p= 37}}
The Type XXIII proved to have excellent handling characteristics, and was highly maneuverable both on the surface and underwater. Its [[crash dive]] time was 9 seconds, and its maximum diving depth was {{convert|180|m|fathom|abbr=off}}. Submerged, its speed was {{convert|12+1/2|kn|km/h|0|abbr=on}}, and while surfaced its speed was {{convert|9|kn|km/h|0|abbr=on}}. A submerged speed of {{convert|10+1/2|kn|km/h|0|abbr=on}} could be attained while snorkeling.{{sfn|Williamson|2005|p=63}}

==Construction==
The first forty-nine boats (''U-2321'' to ''U-2331'', and ''U-2334'' to ''U-2371'') were ordered from Deutsche Werft, Hamburg, while two (''U-2332'' and ''U-2333'') were ordered from Friedrich Krupp [[Germaniawerft]]'s yard at Kiel. Twenty-nine further boats (''U-2372'' to ''U-2400'') were ordered from Deutsche Werft's wartime occupied yards at Toulon, but the first nine of these were scrapped incomplete on the stocks and the remainder never commenced.

Another sixty were ordered to be built by the company at other yards in occupied nations - thirty at [[Genoa]] (''U-2401'' to ''U-2430''), fifteen at [[Monfalcone]] (''U-2431'' to ''U-2445'') and another fifteen at [[Mykolaiv|Nikolaev]] and [[Linz]] (''U-2446'' to ''U-2460''), where a further forty (''U-2461'' to ''U-2500'') were projected but never ordered. All of these were cancelled and never commenced.

Eight hundred additional units were intended to be built by Deutsche Werft - five hundred at Hamburg (''U-4001'' to ''U-4500''), of which the first 120 were ordered and started were subsequently scrapped incomplete, with the others cancelled and never begun; and three hundred at Kiel (''U-4701'' to ''U-5000''), where eleven (''U-4701'' to ''U-4712'', exclude ''U-4708'') were actually built (orders for ''U-4713'' to ''U-4891'' were cancelled, while ''U-4892'' to ''U-5000'' were projected only).

The first Type XXIII, {{GS|U-2321||2}}, was launched from [[Deutsche Werft]] in [[Hamburg]] on 17 April 1944. It was one of six XXIIIs that went on operational patrol around the [[British Isles]] in early 1945. Forty-eight others followed from [[Deutsche Werft]] and fourteen from [[Germaniawerft]] of [[Kiel]]. {{GS|U-4712||2}} was the last one launched, on 1 March 1945.

==Service history==
None of the six operational Type XXIIIs - {{GS|U-2321||2}}, {{GS|U-2322||2}}, {{GS|U-2324||2}}, {{GS|U-2326||2}}, {{GS|U-2329||2}} and {{GS|U-2336||2}} - were sunk by the Allies' ships but they sank four ships for a total of {{GRT|7,392|disp=long}}.

The first war patrol of a Type XXIII began when ''U-2324'' sailed from Kiel on 18 January 1945. Although she was to survive the war, she sank no enemy vessels. The first Type XXIII to achieve combat success was ''U-2322'', commanded by ''[[Oberleutnant zur See]]'' Fridtjof Heckel. Sailing from a Norwegian base on 6 February 1945, she encountered a convoy off [[Berwick-upon-Tweed]], and sank the [[Coastal trading vessel|coaster]] ''Egholm'' on 25 February. ''U-2321'', operating from the same base, sank the coaster ''Gasray'' on 5 April 1945 off [[St Abbs Head]]. ''U-2336'', under the command of ''[[Kapitänleutnant]]'' Emil Klusmeier, sank the last Allied ships lost in the European war on 7 May 1945, when she torpedoed the freighters ''[[SS Sneland I|Sneland I]]'' and {{SS|Avondale Park||2}} off the [[Isle of May]] inside the [[Firth of Forth]].{{sfn|Williamson|2005| pp= 64-65}}

The ''Sneland I'' and the ''Avondale Park'' were sunk around 23:03, less than an hour before the official German surrender, and the ''Avondale Park'' was the last merchant ship to be sunk by a U-boat. At the time it was felt that Kapitänleutnant Klusmeier, who was on his first patrol, had deliberately ignored Dönitz's ceasefire order; Klusmeier claimed that he had never received the order.<ref>{{cite web|last=Lundy|first=Iain|title=Avondale Park|publisher=[[The Scotsman]]|date=25 January 2005|url=http://heritage.scotsman.com/heritage/Avondale-Park.2597758.jp}}</ref>

==Losses==
Seven Type XXIIIs were lost to various causes.
* {{GS|U-2323||2}} was sunk by a [[naval mine]] on 26 July 1944.
* {{GS|U-2331||2}} was lost in a training accident on 10 October 1944.
* {{GS|U-2338||2}} was sunk by British [[Beaufighter]] aircraft which killed 12 crewmen and sank the boat east-northeast of [[Fredericia]] in Denmark on 4 May 1945, before she ever went on combat patrol.
* {{GS|U-2342||2}} was [[Naval mine|mined]] and sunk on 26 December 1944.
* {{GS|U-2344||2}} was accidentally rammed and sunk by {{GS|U-2336||2}} on 18 February 1945.
* {{GS|U-2359||2}} was sunk by Allied aircraft on 2 May 1945.
* {{GS|U-2367||2}} was accidentally rammed and sunk by an unidentified U-boat on 5 May 1945.

In early May 1945, 31 XXIIIs were scuttled by their crews. 20 surrendered to the Allies and were sunk in [[Operation Deadlight]]. Only 3 – {{GS|U-2326||2}} (later British submarine ''N35''), {{GS|U-2353||2}} (later British submarine ''N31'', then Soviet submarine ''M-51''), and {{GS|U-4706||2}} (later Norwegian submarine ''Knerter'') – survived the war.

==Postwar==
One Type XXIII was allocated to the Soviet Union under the terms of the [[Potsdam Agreement]], and a second unit was reportedly salvaged in 1948.<ref name=polmar322/>

In 1956, the [[Bundesmarine]] raised two Type XXIII boats, ''[[German submarine U-2365|U-2365]]'' (scuttled in the [[Kattegat]] in 1945) and ''[[German submarine U-2367|U-2367]]'' (which sank near {{Interlanguage link|Schleimünde|de}} following a collision with another U-boat), and recommissioned them as ''[[German submarine U-2365#Post war service|U-Hai]]'' (Shark) and ''U-Hecht'' (Pike), with pennant numbers S 170 and S 171 respectively.{{sfn|Williamson|2005|pp= 64-65}} ''U-Hai'' sank in a gale off the [[Dogger Bank]] in September 1966, taking 19 of her 20 crewmen with her. Her loss is the greatest maritime post-war disaster that the [[German Navy]] has suffered. The experience gained from the two recommissioned submarines led to the construction of the [[Type 206 submarine]], which was in use until 2011.

==Boats in class==
{{Main|List of Type XXIII submarines}}

Although a total of 980 Type XXIII submarines were planned, many were scrapped incomplete (or indeed never ordered in many cases), only the following 61 vessels were built:
{{Div col|colwidth=10em}}
* {{GS|U-2321||2}}
* {{GS|U-2322||2}}
* {{GS|U-2323||2}}
* {{GS|U-2324||2}}
* {{GS|U-2325||2}}
* {{GS|U-2326||2}}
* {{GS|U-2327||2}}
* {{GS|U-2328||2}}
* {{GS|U-2329||2}}
* {{GS|U-2330||2}}
* {{GS|U-2331||2}}
* {{GS|U-2332||2}}
* {{GS|U-2333||2}}
* {{GS|U-2334||2}}
* {{GS|U-2335||2}}
* {{GS|U-2336||2}}
* {{GS|U-2337||2}}
* {{GS|U-2338||2}}
* {{GS|U-2339||2}}
* {{GS|U-2340||2}}
* {{GS|U-2341||2}}
* {{GS|U-2342||2}}
* {{GS|U-2343||2}}
* {{GS|U-2344||2}}
* {{GS|U-2345||2}}
* {{GS|U-2346||2}}
* {{GS|U-2347||2}}
* {{GS|U-2348||2}}
* {{GS|U-2349||2}}
* {{GS|U-2350||2}}
* {{GS|U-2351||2}}
* {{GS|U-2352||2}}
* {{GS|U-2353||2}}
* {{GS|U-2354||2}}
* {{GS|U-2355||2}}
* {{GS|U-2356||2}}
* {{GS|U-2357||2}}
* {{GS|U-2358||2}}
* {{GS|U-2359||2}}
* {{GS|U-2360||2}}
* {{GS|U-2361||2}}
* {{GS|U-2362||2}}
* {{GS|U-2363||2}}
* {{GS|U-2364||2}}
* {{GS|U-2365||2}}
* {{GS|U-2366||2}}
* {{GS|U-2367||2}}
* {{GS|U-2368||2}}
* {{GS|U-2369||2}}
* {{GS|U-2371||2}}
* {{GS|U-4701||2}}
* {{GS|U-4702||2}}
* {{GS|U-4703||2}}
* {{GS|U-4704||2}}
* {{GS|U-4705||2}}
* {{GS|U-4706||2}}
* {{GS|U-4707||2}}
* {{GS|U-4709||2}}
* {{GS|U-4710||2}}
* {{GS|U-4711||2}}
* {{GS|U-4712||2}}
{{div col end}}

==See also==
*[[British R-class submarine]]
*[[Ha-201-class submarine]]

==References==
{{reflist}}

==Bibliography==
{{refbegin}}
*{{cite book
|last1=Gröner
|first1=Erich
|last2=Jung
|first2=Dieter
|last3=Maass
|first3=Martin
|translator-last1=Thomas
|translator-first1=Keith
|translator-last2=Magowan
|translator-first2=Rachel
|year=1991
|title=German Warships 1815–1945, U-boats and Mine Warfare Vessels
|volume=2
|location=London
|publisher=Conway Maritime Press
|isbn=0-85177-593-4
|ref=CITEREFGröner1991
}}
*{{cite book|first=Gordon|last=Williamson|author-link=Gordon Williamson (writer)|title=Wolf Pack: The Story of the U-boat in World War II|publisher=Osprey|year=2005|isbn=1841768723|url-access=registration|url=https://archive.org/details/wolfpackstoryofu00gord}}
*{{cite book|last1=Williamson|first1=Gordon|first2=Ian|last2=Palmer|title=Kriegsmarine U-boats 1939-45: Vol 2|publisher=Osprey Publishing|year=2002|isbn=1-84176-364-0}}
*{{cite book|last=Polmar|first=Norman|author2=Jurrien Noot|title=Submarines of the Russian and Soviet Navies, 1718-1990|publisher=Naval Institute Press|year=1991|isbn=0-87021-570-1}}
*{{cite book |last=Rössler |first=Eberhard |date=2001 |title=The U-boat: The evolution and technical history of German submarines |location=London |publisher=Cassell & Co |isbn=0-304-36120-8}}
{{refend}}

==Further reading==
{{refbegin}}
* {{cite book |last=Sharpe |first=Peter |date=1998 |title=U-Boat Fact File: Detailed Service Histories of the Submarines Operated by the Kriegsmarine 1935-1945 |location=Leicester |publisher=Midland Publishing |isbn=1-85780-072-9}}
{{refend}}

== External links ==
{{Commons category|Type XXIII submarines}}
* {{cite web
 |url=http://uboat.net/types/xxiii.htm
 |title=Type XXIII Electro boats
 |last=Helgason
 |first=Guðmundur
 |website=German U-boats of WWII - uboat.net
 |access-date= 20 April 2015
}}

{{German Type XXIII submarines}}
{{Uboat}}
{{WWII German ships}}

{{DEFAULTSORT:Type 023 Submarine}}
[[Category:Type XXIII submarines| ]]
[[Category:Submarine classes]]
[[Category:World War II submarines of Germany]]