Salute, Wolfpack!!!
If you don't use map updates then you will need to have your Watch Officer give you his estimate of the target's relative bearing and distance. When he does, start the stopwatch and go to your map and use the protractor and ruler to mark the target.
After 3'15" repeat.... Now you have his speed and course.
You will have to be a little more careful with the time compression, though..
Salute !!
AD