Chart Navigation & Plotting · Sailings — Course from dLat and Departure
If a vessel's run gives a difference of latitude of 30 nm north and a departure of 30 nm east, the course made good is:
- A000°
- B090°
- C045°✓ Correct
- D135°
Explanation
Course = arctan(departure ÷ dLat) = arctan(30 ÷ 30) = arctan(1) = 45°. With northing and easting equal, the resultant course is 045°(T).
Authority: Bowditch (Pub. No. 9), plane sailing
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