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 Komahashi
, was an auxiliary vessel operated by the Imperial Japanese Navy, serving from the 1910s through World War II. Her classification changed numerous times during her operational life. Although officially designated as a submarine tender for most of her career, "Komahashi" very rarely functioned in this role, but was used instead as an oceanographic survey vessel throughout the Pacific, and as a "kaibokan" escort vessel for convoys of merchant ships during the Pacific War.