Navigation General · Radar Plotting
In the relative-motion triangle used to find a target's true course and speed, the line representing own ship's motion (the 'e-r' or 'WO' line) is laid off as:
- AOwn ship's course and speed (distance run) over the plotting interval✓ Correct
- BThe target's range only
- CThe wind direction
- DThe reciprocal of the target bearing
Explanation
In the speed triangle, own ship's vector (course and distance run over the interval) is combined with the observed relative-motion vector of the target to solve for the target's true vector (course and speed). Getting own ship's vector right is essential to the solution.
Authority: Radar plotting; relative motion triangle
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