Submarines of the Imperial Japanese Navy
The submarines that Electric Boat sold to Japan were based on the Holland designs, known as Holland Type VIIs similar to the American s. The five imported Hollands were originally built at Fore River Ship and Engine Company in Quincy, Massachusetts under Busch's direction for the Electric Boat Company back in August–October 1904. They were shipped by freighter from Seattle, Washington in Knock-down kit form to Japan, and then reassembled by Arthur Leopold Busch at the Yokosuka Naval Arsenal, which was then Japan's largest naval shipyard, to become Hulls No. 1 through 5 and were designated Type 1 submarines by the Japanese Navy.
Japanese submarine I-55 (1925)
The four Kaidai Type 3a vessels were the first mass-produced Japanese fleet submarines. Based largely on the indigenous Kaidai Type II ("I-52") a strengthened double hull, their design was also influenced by the largest of the German submarines in Japanese hands, the SM U-125. The hull had almost the same outer dimensions as the "I-52", but the increased thickness of the inner hull permitted a diving depth of 60 meters. Internal volume was slightly increased by making the hull slightly trapezoidal in cross-section, at the expense of 300 tons of additional displacement. External differences included an anti-submarine net cutter on the bow, as well as an O-ring for towing purposes.