Deployment
Kaiten were designed to be launched from the deck of a submarine or surface ship, or from coastal installations as a coastal defence weapon. The only surface ship recorded as equipped to launch Kaitens was the cruiser Kitakami, which took part in sea launch trials of Type–1 Kaitens.
In practice, only the Type–1 craft, using the submarine delivery method, were ever used in combat. Specially equipped submarines carried two to six Kaitens, depending on their class. The Kaitens were lashed to the host vessel on wooden blocks with a narrow access tube connected from the submarine to the lower hatch of the Kaiten. This allowed the Kaiten crews to enter from the host submarine while submerged.
Kaitens had a very limited diving depth, which in turn limited the diving depth of the host submarine. This is one of several factors blamed for the very poor survival rate of submarines using them, eight submarines being lost for the sinking of only two enemy ships and damaging several others.
Once the target was acquired and the host submarine was within range the pilot was briefed, the Kaiten's starting air bottles were charged and the cockpit was ventilated. The pilot then entered the vessel, the gyroscope was programmed with the correct running bearing and depth and the pilot was given his final briefing.
The Kaiten separated from the host submarine and headed at speed in the direction set into the gyroscope. Once within final attack range the Kaiten would surface and the pilot would check his range and bearing via periscope and make any adjustments necessary. He would then submerge to a suitable depth, arm his warhead and proceed on his final attack run. If he missed he could make adjustments and try again. If the mission failed he would detonate his vessel as a last resort.
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