The Holland 602 type submarine, also known as the H class submarine was one of the most numerous submarines of the First World War. The type was designed by the Electric Boat Co. of the United States, but most of the boats were built in Canada by the subsidiary of the British Vickers company. Operators included the United States Navy, the Chilean Navy, the Royal Navy, the Imperial Russian Navy, the Soviet Navy, the Italian Regia Marina, the Royal Canadian Navy, the Royal Dutch Navy, the Ukrainian Navy, the Royal Danish Navy, and the Kriegsmarine.