The torpedo room of USS H-5 in 1919. The breeches of the four 18-inch (457 mm) torpedo tubes are at center
The Holland 602 type submarine, also known as the H-class submarine, was one of the most numerous submarines of World War I. The type was designed by the Electric Boat Co. of the United States, but most of the boats were built abroad: in Canada by the subsidiary of the British Vickers company and in British shipyards.
Origin of project's number is in Electric Boat company rule, according to which, project variant for export purposes was named with replaced digits and with adding 0 between them. Thus, project EB 26 became the project EB 602.[1]
Three prototypes were then built to an improved design 30, with an increased displacement of 358/434 tons. These became the United States H-class submarines and were designated H-1, H-2 and H-3.
In October 1914, after the start of World War I, the British Admiralty ordered ten submarines to design 602E, to be built by Canadian Vickers in Montreal, Quebec. These would become the British H-class submarines. Another ten submarines were secretly constructed at Fore River Yard at Quincy, Massachusetts, in the then neutral United States. This group was impounded by the United States government and ended up in the Chilean Navy and the Royal Canadian Navy after the American declaration of war. A third group, of twenty-five British H-class subs, was constructed in 1917-1919 in Britain, many of them serving in World War II.
In the summer of 1915 eight type 602 submarines were ordered by the Italian Regia Marina. These were built in Montreal, Quebec.
^Морозов, М. (2014). Иностранки Красного флота. Подлодки Сталина [Foreigners in Red fleet. Submarines of Stalin] (in Russian). Moscow: Yauza. p. 11. ISBN978-5-699-71915-0.
