Long Lance needs oxygen installations . For that particular reason it was impractical even on submarines, they created less capable Type 95 torpedoes for those . As for V1/Okha , they could not be launched from torpedo boats, especially Okha . V1 needed catapult for launch from ground ramps . Rocket technology (propellant technology) was not sufficiently advanced at that time to create missiles like later P-15, able to be launched from smaller vessels .