The Imperial Japanese Navy includes a submarine flotilla of seventeen vessels, all except two of which are of the British Holland or Vickers type. Japan commenced the construction of what is now a rapidly increasing and powerful flotilla in 1904 by the purchase of five elementary Holland boats. These, however, are still in the active flotilla and are designated Nos. 1–5. They have a submerged displacement of 120 tons, and are 65 feet in length and 12 feet in beam. Petrol motors of 160 H.-P. drive them at 9 knots on the surface and electric motors of 70 H.-P. at 7 knots when submerged. Their armament consists of one bow expulsion tube with three 18-inch Whitehead torpedoes.

Nos. 6 and 7.

These two vessels were the first submarine boats to be built in Japan, but are of the same type as Nos. 1–5, only larger and faster. They have a submerged displacement of 180 tons, a length of 100 feet and a beam of 10 feet. The petrol engines are of 300 H.-P. and the electric motors of 100 H.-P. The surface and submerged speed is 10 knots and 8 knots an hour, respectively. Their armament consists of one torpedo tube with three 18-inch Whitehead torpedoes.

Nos. 8 and 9.

These two vessels are very similar to the British “C” class, and were built by Messrs. Vickers Ltd. They have a submerged displacement of 320 tons; petrol motors of 600 H.-P., and a surface and submerged speed of 13 knots and 8 knots an hour, respectively. Their armament consists of two bow tubes with four to six 18-inch Whitehead torpedoes. Their complement is sixteen officers and men.

Nos. 10–15.

These six vessels are the same in almost every respect as the later “C” class of British submarines (pages 70–71).

Nos. 16–17^[4].

These two vessels are of the Schneider-Laubeuf or French type. (British “W” class.) Their submerged displacement is about 500 tons, and the horse-power of their surface engines 2,500. The surface and submerged speed is 18 knots and 9 knots respectively. Their armament consists of six torpedo tubes with eight Schneider torpedoes. The complement is about 30 officers and men.

The natural adroitness with which Japanese sailors manipulate complicated machinery, combined with their absolute fearlessness, make them ideal for torpedo work.