Easy way to plot intercept course?

[Hooston]

When in hydrophone or visual contact the most important thing to bear in mind is that if you are on an intercept course the target will be at a constant angle to your boat. This is very useful when doing submerged daylight approaches using the hydrophone. There's an unpronounceable German word for the tactic. Of course you ideally want to get a bit ahead so you can set up a 90 degree AOB shot and not actually crash into the target, so the target should be very slowly drifting backwards from your point of view. If it is drifting forwards you are not going to catch it on your current course and speed. The speed at which the bearing changes also tells you when you are getting close.