Chart Navigation & Plotting · Set and Drift
To make good a desired track in a known current, the navigator solves for the course to steer using a vector triangle in which the current vector is laid off from the:
- AEnd of the intended track vector
- BOrigin (start) of the intended track, with the track and speed-through-water closing the triangle✓ Correct
- CMidpoint of the track
- DDestination only
Explanation
In the current-sailing triangle, the set-and-drift vector is plotted from the starting point along the intended track time base; the course/speed through the water is then laid off to close on the desired track made good. This yields the course to steer and speed of advance.
Authority: Bowditch, American Practical Navigator (Pub. 9), current sailing
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