The was a class of midget submarines of the Imperial Japanese Navy, designed in 1943–1944, and produced from the beginning of 1945. These submarines were meant to meet the invading American naval forces upon their anticipated approach of Tokyo.

History

More than 750 of these midget submarines were planned and by August 1945 about 210 had been manufactured. Most of them were constructed at the Yokosuka shipyard. These submarines had a two-man crew and were fitted with two torpedoes along with a explosive charge intended to be used on a suicide mission. Most of the ''Kairyu'' submarines were based at Yokosuka to defend the entrance of Tokyo Bay in the event of a United States invasion of mainland Japan. Some of these subs were also stationed in the Moroiso and

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inlets on the southern tip of the Miura Peninsula where a training school had also been set up. Due to Japan's surrender in August 1945, none of these submarines ever saw action. File:Kairyu class submarine.jpg, A Kairyu in the Yamato Museum, Kure File:Kairyu_class_submarine_at_the_Yamato_Museum_Oct_2008.jpg, Rear-end of a Kairyū submarine

Technical details

All members of the Kairyu class were constructed from 3 sections of welded steel bolted together. The sections were the fore (warhead), mid (diesel engine, ballast, fuel, controls and batteries) and finally the aft (motor and control planes). The bow section could be installed with or without a warhead. Following on from the bow was the central section, first in this section was the

batteries Battery most often refers to: * Electric battery, a device that provides electrical power * Battery (crime), a crime involving unlawful physical contact Battery may also refer to: Energy source *Automotive battery, a device to provide power t ...

for the electric motor and the air flasks. Next was the pilot area. He would have numerous controls including controls for the fore and aft dive planes and rudders, valves for oil, fuel and water and the periscope raise/lower controls. Behind the pilot would be the main

ballast tank A ballast tank is a compartment within a boat, ship or other floating structure that holds water, which is used as ballast to provide hydrostatic stability for a vessel, to reduce or control buoyancy, as in a submarine, to correct trim or list, ...

and fuel tank. Abaft the fuel tank and ballast tank was a in-line six

diesel Diesel may refer to: * Diesel engine, an internal combustion engine where ignition is caused by compression * Diesel fuel, a liquid fuel used in diesel engines * Diesel locomotive, a railway locomotive in which the prime mover is a diesel engin ...

engine, followed by the aft trim tanks, gearbox and reduction motors and finally the electric motor and

propeller A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...

s. In the

conning tower A conning tower is a raised platform on a ship or submarine, often armored, from which an officer in charge can conn the vessel, controlling movements of the ship by giving orders to those responsible for the ship's engine, rudder, lines, and gro ...

there was usually a Type 4 magnetic compass however some early models had a Type 97 gyrocompass in the boat itself.Rekishi Gunzo, p. 119.

Modification 3

While both the original and second modifications were practically identical, the third modification of the class had some notable differences. The overall length was longer. The forward dive planes were moved forward of the conning tower. There was no external magnetic compass and the fuel tank was installed before the pilot's control area. There was also a second periscope aft of the conning tower. This model could very well have been used for training purposes with a complement of 3.

Survivors

A Kairyū-class submarine, cutaway to show interior details, is on display at the US Navy Submarine School at Naval Submarine Base New London in Groton, Connecticut. It has been there since at least the mid-1960s. Another is known to survive at the Yamato Museum, fully intact.

References

*''Rekishi Gunzo'', History of the Pacific War Volume 36, ''Kairyu and Kaiten'',

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, Tokyo, Japan, 2002, .

External links

U.S. Naval Historical Center

Pacific War Online Encyclopedia
{{DEFAULTSORT:Kairyu Class Submarine Submarine classes World War II suicide weapons of Japan World War II submarines of Japan Midget submarines Japan campaign