Coastal Skipper and Yachtmaster Quiz · Electronic navigation
You have marked this target three times and extended the line through the marks. If neither of you alters, about how close will she pass?
A radar screen with your heading at the top and three range rings, 2 miles apart. One target has been marked three times, at 1200, 1206 and 1212, each mark closer than the last, coming down from ahead on the port bow. A dashed gold line extends the three marks onwards across the screen. It passes to the right of the centre.
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About 2 miles. On a relative motion display a target moves across the screen along a straight line as long as both vessels hold course and speed. The closest point of approach is where that line passes nearest to the centre, which is you: here it just touches the 2 mile ring. A line pointing straight at the centre is a steady bearing and means risk of collision.
