You can run in your torp in CW if you fire one at too close a target. The only thing the enemy needs to do is dropping a noisemaker, the torp will turn and say hello to your sub.
I never saw a enemy torp hitting the enemy ship, I think the devs have made this impossible, but not for your sub
In the game, changing your vertical position quickly and making at least a 100° turn at 25 knots should evade the torp for some time, but to re-direct it in one specific position just make a smaller turn, but still go up or down quickly and the torp should run in that direction under or over your sub. So theoretically it works, but as said: because it would be too easy to get rid of an enemy, the devs must have disabled friendly AI torp hits (I don't know, I'll be happy to hear anyone saying the contrary). Also the enemy must be *really* close, 2-3 ky at maximum for the torpedo to follow him.
What is possible is: colliding with the enemy, this will take you severe hull damage and floodings,more than a torpedo hit.