From wiki:
"The two torpedoes were carried in troughs set into the rear deck in a manner derived from that used by the British WW I-era coastal motor boats captured by the Soviets during Russian Civil War. The torpedoes were shoved out the back of the trough by an arbor with a bell-shaped head that was activated by an explosive charge, but the torpedo motor was not activated until a wire trailing from the boat snapped, giving the boat time to turn away from the target. This launching system was very light, but it required additional training to properly aim the torpedo and prior coordination when making massed torpedo attacks to prevent the boats from ramming each other or the torpedoes."