The ship on the wheel is the target ship. Point the ship's bow right or left as you see it thru the scope. Now a 90 degree angle is the easiest to determine - you shouldn't see the front or back of the superstructure and goalpost masts merge into one stick. It takes a bit of judgement, but try to determine to what degree the target ship is veering away or toward you.
The angle on the bow is what the target ship's lookout sighting report would say - "Sub sighted 60 degrees port".
|