[TorpX]

Originally Posted by Chucktown

What is the best way to find a suitable position for attacking a convoy without using any kind of help from map updates or using the watch officer for range estimation on visual contacts?

Like Armistead said, you can use radar, If you don't have radar, there really isn't a good way to determine course and speed, without visual observation. This usually means careful observations, judgment, and lots of plotting. If it was practical to stalk and target enemy ships without recourse to visual sightings, subs wouldn't need periscopes. Not every contact could be intercepted, and not every interception would result in a successful attack.

Also, it will help you to know what a Normal Approach Course is, and why it was used. However, it doesn't tell you anything about the enemy's course or speed.