The sad thing is that in Silent Hunter 2 the TDC was absolutely perfect. And because you did input the target course and speed, and the bearing was updated as you moved your scope left or right, it allowed you firing at multiple targets that share both course and speed but not position (A convoy, to be more precise) just by looking at the next target and firing.
So easy....you get a convoy course and speed. Put your crosshair in the first target, f.e. bearing 10, fire 1, move scope right to next target, f.e. bearing 25º, wait some seconds until TDC computes all according to new bearing and when green light comes (Solution ready) then fire 2!...and so on. That's how germans did it in real life
