Salute, Jason !!
Try this and see if it works:
Plot the target so as to work out his course and speed.
Position your boat as to get ahead of the targets track so you can shoot as close to 90 degrees AOB as possible.
Train your scope to 0 degrees (if firing forward tubes). MANUALLY input into TDC the target speed and the AOB that it will be when the torps impact
Throw the TDC switch which will input the data to the torpedoes.
Look at the gyro angle and turn the scope so that the angle is 0
When the target passes the crosshairs LOS !!!
What can goof you up is if you have to input a "snap shot" in a hurry and forget to throw the switch to input the data to the torps. Then who knows where they go !!
AD