If you are getting within 2000m or less, the intended target is as good as dead. What I do is manually dial in the speed of the merchants. Normally they do 7kts. I dial that in. I position myself to be somewhere around 90 degrees to the target. I never use magnetic, only contact on the torps. That is just me I guess. Once your intended target has come into your settings before letting the torps go, fire away. Make sure those doors are open because you will loose three seconds on the run time of the torpedo and probably miss. I like to position myself so I can sit and wait for the victim to come to me. That gives me plenty of time to get my settings where I want them. Once done, I kick back and wait for my numbers to match and watch the fireworks.
