Submarines of the Imperial Japanese Navy
In 1904 Kawasaki Dockyard Company purchased plans for a modified version directly from Holland, and built two boats (Hulls No. 6 and 7), with the help of two American engineers, Chase and Herbert, who had been assistants to Holland. The Kawasaki-type submarines displaced 63 and 95 tons when submerged, and measured in overall length, respectively. both vessels measured at the beam. This contrasted with the original five imported Hollands-type submarines which had arrived that same year, at over 100 tons submerged, in overall length and beam. The Kawasaki Type #6 and #7 submarines had gained extra speed and reduced fuel consumption by . However both boats could launch only one torpedo, and each was manned by 14 sailors, whereas the imported Holland-type submarines could fire two torpedoes and could be operated by 13 sailors. This new type was designated the Type 6 submarine by the Imperial Japanese Navy, and was used primarily for test purposes.
Japanese submarine tender Karasaki
At the end of 1904, "Karasaki Maru" was sent to the Yokosuka Naval Arsenal for conversion into a submarine tender. She was officially commissioned into the Imperial Japanese Navy on 4 July 1905. On 8 March 1906, she was renamed "Karasaki", and was officially re-designated as a torpedo boat tender. In August 1912, the Imperial Japanese Navy abolished the torpedo boat tender classification, and "Karasaki" was re-designated as a second-class "kaibokan". However, the designation of torpedo boat tender was revived in April 1920. From 1924, "Karasaki" was then assigned to the submarine training school at Kure Naval District, and from 1 December 1924, was again officially designated as a submarine tender.