View source for Jymy-class motor torpedo boat

{{Short description|WW II naval boat}}
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{{Infobox ship class overview
|Name=''Jymy'' class
|Builders=Cantieri Baglietto, [[Genoa]], Italy
|Operators=* {{navy|Kingdom of Italy}}
* {{navy|Finland}}
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|Total ships completed=4
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|Total ships retired=4
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{{Infobox ship characteristics
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|Ship type=[[Motor torpedo boat]]
|Ship displacement={{cvt|25|t|LT|lk=on}}
|Ship length={{cvt|18.7|m|ftin}}
|Ship beam={{cvt|4.7|m|ftin}}
|Ship draught={{cvt|1.5|m|ftin}}
|Ship power=
|Ship propulsion= 2 × [[Isotta-Fraschini]] petrol engines, {{cvt|2000|bhp|lk=on|order=flip}}
|Ship speed={{Convert|42|kn|lk=in}}
|Ship range=*{{cvt|1100|nmi|abbr=on}} at {{Convert|6|kn|abbr=on}}
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|Ship complement=10
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|Ship armament=*1 × [[Cannone-Mitragliera da 20/65 modello 35 (Breda)|{{cvt|20|mm}} Breda gun]]
*1 × {{cvt|12.7|mm}} machine gun
*2 × {{cvt|450|mm|in}} [[torpedo tube]]s
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The '''''Jymy''-class motor torpedo boats''' (English: "Rumble") or '''J class''' was an [[Italy|Italian]]-designed and built class of [[motor torpedo boat]]s, seeing service during [[World War II]] with the [[Royal Italian Navy]] and later with the [[Finnish Navy]]. The four boats of the J class were built by [[Cantieri Baglietto]] in [[Genoa]], Italy and purchased by the Finns on 5 June 1943. Following World War II, the vessels were rearmed according to the [[Paris Peace Treaties, 1947|Paris Peace Treaty of 1947]], losing their [[torpedo]] capabilities and given more guns. They were removed from service in 1961.

==Design and description==
The J class were initially four [[motor torpedo boat]]s of the Italian {{sclass|MAS 526|motor torpedo boat|4}}. The ''MAS 526'' class were a lengthened version of the preceding {{sclass|MAS 501|motor torpedo boat|4}} with a [[Displacement (ship)|displacement]] of {{convert|25|t|LT|lk=on}}, measuring {{convert|18.7|m|ftin}} long with a [[Beam (nautical)|beam]] of {{cvt|4.7|m|ftin}} and a [[Draft (hull)|draught]] of {{cvt|1.5|m|ftin}}. The motor torpedo boats were propelled by two propellers powered by two [[Isotta-Fraschini]] [[petrol engine]]s creating {{convert|2000|bhp|lk=on|order=flip}}. They had a maximum speed of {{convert|42|kn|lk=in}}. The vessels carried {{cvt|1.25|t}} of fuel giving them a range of {{convert|1100|nmi|lk=in}} at {{convert|6|kn}} or {{cvt|360|nmi}} at 42 knots. The J class were armed with two {{convert|450|mm|adj=on}} [[torpedo tube]]s, one [[Cannone-Mitragliera da 20/65 modello 35 (Breda)|{{cvt|20|mm}} Breda gun]] and one {{cvt|12.7|mm}} machine gun.{{sfn|Roberts|1980|p=313}}{{sfn|Westerlund|1980|p=336}}

==Vessels of the class==
{| class="wikitable" style="font-size:95%;"
|-
! colspan="6" |''Jymy'' class construction data{{sfn|Westerlund|1980|p=367}}{{sfn|Fraccaroli|1974|pp=168–169}}
|-
! scope="col"| Number
! scope="col"| Ship
! scope="col"| Builder
! scope="col"| Launched
! scope="col"| Commissioned
! scope="col"| Fate
|-
| scope="row"| J 1
|''Jylhä'' (ex-''MAS 526'')
| rowspan="4"| Baglietto, Varazze
| 22 August 1938
| 2 March 1939
| Acquired by Finland in 1943, stricken 1961.
|-
| scope="row"| J 2
| ''Jyry'' (ex-''MAS 527'')
| 30 January 1939
| 30 March 1939
| Acquired by Finland in 1943, stricken 1961.
|-
| scope="row"| J 3
| ''Jyske'' (ex-''MAS 528'')
| 28 February 1939
| 29 August 1939
| Acquired by Finland in 1943, stricken 1961.
|-
| scope="row"| J 4
|''Jymy'' (ex-''MAS 529'')
| 3 April 1939
| 30 June 1939
| Acquired by Finland in 1943, stricken 1961.
|-
|}

==Construction and career==
All four vessels were constructed in Italy and served with the [[Royal Italian Navy]] during [[World War II]]. Finland acquired the four motor torpedo boats on 5 June 1943.{{sfn|Westerlund|1980|p=367}} The [[Paris Peace Treaties, 1947|Paris Peace Treaty of 1947]] was signed following the end of World War II, and Finland was prohibited by the treaty from having torpedo-carrying vessels. The ships were converted into motor gunboats in 1949, in accordance with the treaty.{{sfn|Blackman|1953|p=141}} The vessels were rearmed with a {{cvt|40|mm}} gun in addition to the 20 mm gun.{{sfn|Fraccaroli|1974|pp=168–169}} Their maximum speed was reduced to {{convert|35|kn}} and their displacement decreased to {{convert|22|t|LT}}.{{sfn|Blackman|1960|p=141}} The J-class vessels were stricken from the naval vessel register in 1961.{{sfn|Westerlund|1980|p=367}}

==Citations==
{{reflist}}

==References==
* {{cite book |editor-last=Blackman |editor-first=Raymond V. B. |year=1953 |title=Jane's Fighting Ships 1953–54 |location=London |publisher=Sampson, Low and Marston |oclc=913556389}}
* {{cite book |editor-last=Blackman |editor-first=Raymond V. B. |year=1960 |title=Jane's Fighting Ships 1960–61 |publisher=Sampson Low, Marston & Co. |location=London |oclc=946722815}}
* {{cite book |last=Fraccaroli |first=Aldo |orig-year=1968 |year=1974 |title=Italian Warships of World War II |publisher=Ian Allan |location=London |isbn=0-7110-0002-6}}
* {{cite book |last=Roberts |first=John |chapter=Italy |editor-last=Chesneau |editor-first=Roger |year=1980 |title=Conway's All the World's Fighting Ships 1922–1946 |publisher=Conway Maritime Press |location=Greenwich, UK |isbn=0-85177-146-7 |pages=280–317}}
* {{cite book |last1=Westerlund |first1=Karl-Erik |chapter=Finland |editor-last=Chesneau |editor-first=Roger |year=1980 |title=Conway's All the World's Fighting Ships 1922–1946 |publisher=Conway Maritime Press |location=Greenwich, UK |isbn=0-85177-146-7 |pages=363–367}}

{{WWII Finnish ships}}

[[Category:Torpedo boats of the Finnish Navy]]
[[Category:Torpedo boat classes]]