The five boats of the H class were built by Cantieri Baglietto in Genua, Italy and transported to Finland over land and sea, a journey that took 11 days. These boats had been ordered during the Winter War in 1940, but due to lack of material, the production took time, and became ready by 1943. Their main engines, originally aircraft engines, were of bad quality. Therefore the engines had to be spared and not used at all for training. After only 20 hours of service, the engines had deteriorated greatly in power. The Finnish Navy stopped using these as torpedo boats after the summer of 1943 and used them instead as fast mine-layers and smoke dischargers.
The ships were converted into patrol boats in 1949, in accordance with the Paris peace treaty. They were then equipped with two 20 mm anti-aircraft cannons and two heavy machine guns. The H class were stricken from the lists in 1963 and auctioned out. H 4 have survived until today as the M/Y Odysses.