Any Guess As To Why?

[Simmy]

I have just started playing with the manual TDC.
I have it figured out, more or less, have sank a
fair number of ships. But then right when I think
I have this down cold my torps miss, passing behind
the ship. Maybe a matter of the input speed being
incorrect, but I am pretty careful of watching that.
Is there anything else I might be overlooking that you
can think of?

Thanks much...