View source for Japanese submarine I-51

{|{{Infobox ship begin}}
{{Infobox ship image
| Ship image=HIJMS I51-1924.jpg
| Ship caption=''Submarine No. 44'' in 1924
}}
{{Infobox ship career
| Hide header=
| Ship country=Japan
| Ship flag= {{shipboxflag|Empire of Japan|naval}}
| Ship name= ''Project S22''
| Ship ordered=1918 Fiscal Year
| Ship awarded=
| Ship builder=[[Kure Naval Arsenal]], [[Kure, Hiroshima|Kure]],&nbsp;[[Japan]]
| Ship original cost=
| Ship yard number=
| Ship way number=
| Ship laid down=6 April 1921
| Ship launched=29 November 1921
| Ship sponsor=
| Ship christened=
| Ship completed=20 June 1924, as ''Submarine No. 44''
| Ship commissioned=20 June 1924
| Ship renamed=''Submarine No. 44'' by 20&nbsp;June&nbsp;1924
}}
{{Infobox ship career
| Hide header=yes
| Ship renamed=''I-51'', 1 November 1924
| Ship homeport=[[Kure Naval District]]
}}
{{Infobox ship career
| Hide header=yes
| Ship decommissioned=15 December 1938
| Ship in service=
| Ship out of service=
| Ship struck=1 April 1940
}}
{{Infobox ship career
| Hide header=yes
| Ship renamed=''Haikan No. 3'' or ''Haisein&nbsp;No.&nbsp;3'' on 1&nbsp;April&nbsp;1940
| Ship fate=*[[Hulk (ship)|Hulked]] 1&nbsp;April&nbsp;1940
*Sold and scrapped 1941
| Ship notes=
| Ship badge=
}}
{{Infobox ship characteristics
| Hide header=
| Header caption=
| Ship class={{sclass|Kaidai|submarine}} (Type I)
| Ship displacement=
*{{Convert|1833|LT|t|0|lk=on|abbr=on}} surfaced
*{{Convert|2602|LT|t|0|abbr=on}} submerged
| Ship length= {{Convert|99.44|m|ftin|abbr=on}} 
| Ship beam= {{Convert|8.81|m|ftin|abbr=on}} 
| Ship height=
| Ship draught= {{Convert|4.6|m|ftin|abbr=on}} 
| Ship propulsion=
*4 × [[Sulzer (manufacturer)|Sulzer]] [[diesel engines]],{{Convert|5200|hp|MW|abbr=on}} (2&nbsp;removed&nbsp;1932)
*4 x [[electric motor]]s, {{Convert|2000|hp|MW|abbr=on}}
*4 shafts (2&nbsp;removed&nbsp;1932)
| Ship speed= 
*{{Convert|18.5|kn|lk=in}} (surfaced)
*{{Convert|8.4|kn|abbr=on}} (submerged)
| Ship range= 
*{{Convert|20000|nmi|km|abbr=on}} @ {{Convert|10|kn|abbr=on}} (surfaced)
*{{Convert|100|nmi|km|abbr=on}} @ {{Convert|4|kn|abbr=on}} (submerged)
| Ship endurance={{Convert|47.5|m|ft|abbr=on }}
| Ship test depth=
| Ship complement=70 officers and men
| Ship sensors=
| Ship EW=
| Ship armament= 
*6 × {{Convert|533|mm|0|abbr=on}} forward [[torpedo tube]]s
*2 × {{Convert|533|mm|0|abbr=on}} aft [[torpedo tube]]s
*1 x [[12 cm/45 10th Year Type naval gun]] (removed&nbsp;1932)
*24 × [[naval mine]]s
|Ship aircraft=1 × [[Yokosuka E6Y|Yokosho&nbsp;2-Go]] or [[Yokosuka E6Y|Yokosho&nbsp;2-Go&nbsp;Kai]] [[floatplane]] (added&nbsp;1931)
|Ship aircraft facilities=*1 x [[hangar]] (added&nbsp;1931)
*1 x [[aircraft catapult]] (added&nbsp;1933) 
| Ship notes=
}}
|}
{{nihongo|'''''I-51'''''|伊号第五一潜水艦|I-gō Dai Gojū-ichi sensuikan}}, previously '''''Project S22''''' and '''''Submarine No. 44''''', was a [[submarine]] in commission in the [[Imperial Japanese Navy]] from 1924 to 1938. Although not a successful design, she was the [[lead vessel]] and prototype of the Japanese {{sclass|Kaidai|submarine}}s which served in [[World War II]]. The Japanese also used her for early experiments in the development of [[submarine aircraft carrier]]s.

==Background==
Following [[World War I]], the [[Imperial Japanese Navy General Staff]] began to re-consider [[submarine warfare]] as an element of fleet strategy. Before the war, the Imperial Japanese Navy regarded submarines as useful only for short-range coastal point defense. However, based on the success of the [[Imperial German Navy]] in deploying long-range [[cruiser submarine]]s for [[commerce raiding]] during World War I, Japanese strategists came to realize the potential for using submarines for long-range reconnaissance, as well as in a [[war of attrition]] against an enemy fleet approaching [[Japan]].<ref name=Peattie>Peattie, Evans, ''Kaigun'', p.114,  212-214</ref> Procurement of a large, long-range Japanese submarine was authorized in [[fiscal year]] 1918 under the [[Eight-eight fleet|Eight-six fleet program]], under the designation '''''Project S22'''''.

==Design==
Japanese ties to the [[United Kingdom]] via the [[Anglo-Japanese Alliance]] were still strong in the immediate aftermath of World War I, and ''Project S22'' was based on the latest [[Royal Navy]] design, the [[British K-class submarine]].  With a [[Displacement (ship)|displacement]] of 1390 [[Displacement tonnage|tons]], ''Project S22'' was the largest submarine built in Japan up to that time. In order to attain a design speed of {{convert|23|kn}} on the surface and {{convert|15|kn}} submerged, the design required four [[diesel engine]]s driving four [[Propeller|screws]]. To accommodate these engines, a [[double hull]] design was used, with [[Hull (ship)|hulls]] joined side-by-side, forming a sideways figure "8". As completed, {{nowrap|''I-51''}} achieved only {{convert|18.4|kn}} surfaced and {{convert|8.4|kn}} submerged during [[Sea trials|trials]], but had an unrefueled range of {{convert|20,000|nmi|lk=on}}, which was considered remarkable for the time.<ref name=Peattie/>

Despite various technical achievements the Japanese made in ''I-51''′s design, they did not regard her as a successful design, largely because of problems with her [[Sulzer (manufacturer)|Sulzer]] diesel engines. She saw only limited fleet service.

==Construction and commissioning==
'''''Project S22''''' was [[Keel-laying|laid down]] at the [[Kure Naval Arsenal]] in [[Kure, Hiroshima|Kure]], Japan, on 6 April 1921, [[Ceremonial ship launching|launched]] on 29 November 1921, and completed on 20 June 1924,<ref name=Jentsura>Jentsura, ''Warships of the Imperial Japanese Navy, 1869-1945'', p.190</ref><ref name=ijnsubsiteI51>{{cite web |url= http://www.ijnsubsite.info/I-Sub%20Details/I-51.htm |title=I-51 ex No.44 |first1= |last1= |work=iijnsubsite.info |date=27 August 2018|accessdate=1 January 2022}}</ref> by which time she had received the name {{nihongo|'''''Submarine No.44'''''|第四四号潜水艦 |Dai-Yonjūyon-go sensuikan}}.<ref name=ijnsubsiteI51/>

==Operational history==

Upon completion, ''Submarine No. 44'' was [[Ship commissioning|commissioned]] and attached to the [[Kure Naval District]].<ref name=ijnsubsiteI51/> From 17 July 1924 to 1 May 1925, she was assigned to Submarine [[Squadron (naval)|Squadron]] 2 in the [[2nd Fleet (Imperial Japanese Navy)|2nd Fleet]], a component of the [[Combined Fleet]],<ref name=ijnsubsiteI51/> and during her stint with the squadron she was renamed '''''I-51''''' on 1 November 1924.<ref name=ijnsubsiteI51/> She returned to duty in the Kure Naval District from 1 May until 1 December 1925, when she was assigned along with the submarine {{ship|Japanese submarine|I-52||2}} to Submarine [[Division (naval)|Division]] 17, which was reactivated that day as a component of Submarine Squadron 2, which in turn remained part of the 2nd Fleet in the Combined Fleet.<ref name=ijnsubsiteI51/><ref name=ijnsubsitesubdiv17>{{cite web |url= http://www.ijnsubsite.info/Subdivs/subdiv17.htm |title=Submarine Division 17 |first1= |last1= |work=iijnsubsite.info |date=|accessdate=1 January 2022}}</ref> On 10 December 1928, Submarine Division 17 was reassigned to the Kure Naval District.<ref name=ijnsubsiteI51/>

''I-51'' remained a part of Submarine Division 17 until the division's deactivation on 11 November 1935.<ref name=ijnsubsiteI51/><ref name=ijnsubsitesubdiv17/> The division was assigned to the Kure Naval District throughout the years from December 1928 to November 1935, also serving in the Kure Defense Division from 30 November 1929 to 1 December 1930 and again from 1 October 1932 to 1 January 1933.<ref name=ijnsubsiteI51/><ref name=ijnsubsitesubdiv17/> Unsuccessful in fleet service due to problems with her diesel engines, ''I-51'' never returned to the fleet after Submarine Division 17's reassignment to the Kure Naval District in 1928. Instead, she was retained as part of Submarine Division 17 at the Kure Naval Arsenal for crew training and as a test bed for various submarine technologies.

In May 1929, ''I-51'' began experimental work in submarine-based operation of the Yokosho 2-Go, the first [[prototype]] of the [[Yokosuka E6Y]] [[floatplane]].<ref name=ijnsubsiteI51/>{{sfn|Volkov|2014}} She completed this testing program by September 1931.{{sfn|Mikesh|Abe|1990|page=279}} In 1931 she was fitted with an aircraft [[hangar]] which could house one floatplane which could be raised and lowered into the water by a [[Crane (machine)|crane]], and she began testing the operation of the second E6Y prototype, the Yokosho 2-Go Kai.{{sfn|Volkov|2014}} In 1933, an [[aircraft catapult]] was installed on her deck,{{citation needed|date=January 2022}} making her the forerunner of the Japanese [[submarine aircraft carrier]]s of [[World War II]].

In addition to her experimental work, ''I-51'' began duty in 1930 as a training submarine at Kure.<ref name=ijnsubsiteI51/> In 1932, two of her diesel engines and their associated shafts were removed, as was her main [[deck gun]].<ref name=Jentsura/>

After the deactivation of Submarine Division 17 on 15 November 1935,<ref name=ijnsubsitesubdiv17/> ''I-51'' was attached directly to the Kure Naval District, and she continued her training duties until she was [[ship decommissioning|decommissioned]] and placed in the Fourth Reserve on 15 December 1938.<ref name=ijnsubsiteI51/> While in the Fourth Reserve, she was reassigned to the [[Maizuru Naval District]] on 15 November 1939.<ref name=ijnsubsiteI51/>

''I-51'' was removed from the [[navy list]] on 1 April 1940,<ref name=ijnsubsiteI51/> and she was [[Hulk (ship)|hulked]] that day with the name ''Haikan No. 3''<ref name=ijnsubsiteI51/> or ''Haisen No. 3''.<ref name=ijnsubsiteI51/> She was sold and scrapped in 1941.<ref name=ijnsubsiteI51/>

==References==
===Footnotes===
{{Reflist}}

===Bibliography===
* {{cite book|last=Boyd|first=Carl|title=The Japanese Submarine Force in World War II|publisher=[[Naval Institute Press]]|location=[[Annapolis]], MD|year=2012|isbn=978-1557500151 }}
* {{cite book|last1=Peattie|first1=Mark R.|last2=Evans |first2=David C. |title=Kaigun: Strategy, Tactics, and Technology in the Imperial Japanese Navy, 1887-1941|publisher=Naval Institute Press|location=Annapolis, MD|year=1997|isbn=0-87021-192-7}}
* {{cite book|last=Jentsura|first=Hansgeorg|title=Warships of the Imperial Japanese Navy, 1869-1945|publisher=Naval Institute Press|location=Annapolis, MD|year=1976|isbn=0-87021-893-X}}
* {{cite book|last1=Mikesh|first1=Robert C.|first2=Shorzoe|last2=Abe|title=Japanese Aircraft 1910-1941|location=London|publisher=Putnam|year=1990|isbn=978-0-851-77840-2}}
*{{cite journal |last1=Passingham|first1=Malcolm|title=Les hydravions embarqués sur sous-marins |journal=Avions: Toute l'aéronautique et son histoire |date=February 2000 |issue=83 |pages=7–17 |trans-title=Submarine-carried Seaplanes |language=French |issn=1243-8650}}
* {{cite book|last=Stille|first=Mark|title=Imperial Japanese Navy Submarines 1941-45|publisher=Osprey|year=2007|isbn=978-1846030901 }}
* {{cite web|last=Volkov|first=Dale|url=http://www.airwar.ru/enc/other1/e6y.html|title=E6Y|website=Уголок неба|year=2014|language=ru|access-date=7 October 2018}}

{{Kaidai type submarine}}

{{DEFAULTSORT:I-51}}
[[Category:1921 ships]]
[[Category:Ships built by Kure Naval Arsenal]]
[[Category:Kaidai-class submarines]]