Torpedo targetting problems!!
 

I am trying to sink the ships in the training mod. Problem I'm having is that I keep missing the ships stern by a few feet.
Whenever I line up the shot at the sitting duck cargo ship (That's what I call it cause it just sits there in front of you.), It does takes off all of a sudden to get a away from my torp. Now while I do have a problem with several tons of cargo ship being able to just jump off the starting line like a quarter mile dragster I'll forgo that little annoyance for now.
My problem is that when I target the ship when it's moving I always show the same speed even if I start the timer on the ship and stop it way out in front to compensate for the fact that I keep missing the stern of the ship by a few feet. If I put the crosshairs on the midships when I start the clock and then stop it way out in front of the ship shouldn't the speed be different than if I start and stop the timer on the ships midsection? Well it doesn't. What am I doing wrong?
If I could manually input speed I could compensate better and get a more accurate gyro angle. I think the speed is not accurate.

Ignore this cargo ship as it highlights a game design flaw, in that the ships can go from stop to full speed within a minute and move instantly.

The only way to sink this vessel is actually to target it from a distance closer to 1000 metres and it suddenly is less 'all seeing' and all sprinting.

If you are missing to the stern by just a few feet, here's a trick that helps:

Press Q to open the selected torpedo tube's door. Do this a few seconds before firing. This will cut down on the time it takes for the torpedo to actually fire, and will make your shot more accurate. Q always opens only the door of the active torpedo. If you want more than one door open, you can select a spread (tricky) or simply flip the door switches above the TDC desk in the command room.

Is there a way to manually input speed of target?

Yup. You can manually enter target speed from the TDC screen. You'll have to click the red input on/off switch on the TDC screen - you can manually enter data when it's green.