The ''Jymy''-class motor torpedo boats (English: "Rumble") or J class was an

Italian Italian(s) may refer to: * Anything of, from, or related to the people of Italy over the centuries ** Italians, an ethnic group or simply a citizen of the Italian Republic or Italian Kingdom ** Italian language, a Romance language *** Regional Ita ...

-designed and built class of motor torpedo boats, seeing service during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

with the

Royal Italian Navy The ''Regia Marina'' (; ) was the navy of the Kingdom of Italy (''Regno d'Italia'') from 1861 to 1946. In 1946, with the birth of the Italian Republic (''Repubblica Italiana''), the ''Regia Marina'' changed its name to '' Marina Militare'' (" ...

and later with the

Finnish Navy The Finnish Navy ( fi, Merivoimat, sv, Marinen) is one of the branches of the Finnish Defence Forces. The navy employs 2,300 people and about 4,300 conscripts are trained each year. Finnish Navy vessels are given the ship prefix "FNS", short for ...

. The four boats of the J class were built by Cantieri Baglietto in

Genoa Genoa ( ; it, Genova ; lij, Zêna ). is the capital of the Italian region of Liguria and the List of cities in Italy, sixth-largest city in Italy. In 2015, 594,733 people lived within the city's administrative limits. As of the 2011 Italian ce ...

, Italy and purchased by the Finns on 5 June 1943. Following World War II, the vessels were rearmed according to the Paris Peace Treaty of 1947, losing their

torpedo A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, su ...

capabilities and given more guns. They were removed from service in 1961.

Design and description

The J class were initially four motor torpedo boats of the Italian . The ''MAS 526'' class were a lengthened version of the preceding with a

displacement Displacement may refer to: Physical sciences Mathematics and Physics *Displacement (geometry), is the difference between the final and initial position of a point trajectory (for instance, the center of mass of a moving object). The actual path ...

of , measuring long with a

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of and a draught of . The motor torpedo boats were propelled by two propellers powered by two Isotta-Fraschini

petrol engine A petrol engine (gasoline engine in American English) is an internal combustion engine designed to run on petrol (gasoline). Petrol engines can often be adapted to also run on fuels such as liquefied petroleum gas and ethanol blends (such as ''E ...

s creating . They had a maximum speed of . The vessels carried of fuel giving them a range of at or at 42 knots. The J class were armed with two

torpedo tube A torpedo tube is a cylindrical device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, and deck-mounted units (also referred to as torpedo launchers) installed aboa ...

s, one Breda gun and one machine gun.

Vessels of the class

Construction and career

All four vessels were constructed in Italy and served with the

during

. Finland acquired the four motor torpedo boats on 5 June 1943. The 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. The vessels were rearmed with a gun in addition to the 20 mm gun. Their maximum speed was reduced to and their displacement decreased to . The J-class vessels were stricken from the naval vessel register in 1961.

Citations

References

* * * * * {{WWII Finnish ships Torpedo boats of the Finnish Navy Torpedo boat classes