Kawasaki built two boats (Hulls No. 6 and 7), with the help of two American engineers, Chase and Herbert, who had been assistants to John Philip Holland. The Kawasaki-built submarines displaced 63 or 95 tons when submerged, and measured 73 or 84 feet in overall length, respectively, and were thus longer and displaced less than the original five imported Holland-type submarines which had arrived that same year. However, they had almost double the engine power, which gave extra speed and reduced fuel consumption. On the other hand, both vessels could launch only one 18-inch 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.
