USCG Exam PracticePlot true course and distance between two charted points
A navigator plots a course line from Point A to Point B on a Mercator chart. The true course is read from the compass rose. Which of the following statements about that course line is correct?
- A. It represents a great circle route and will appear curved on the chart
- ✓ It represents a rhumb line and maintains a constant true bearing throughoutCorrect
- C. It represents a rhumb line but the bearing changes as latitude changes
- D. It represents the course made good after accounting for current set and drift
Why B is correct
A straight line drawn on a Mercator chart is a rhumb line, which by definition maintains a constant true bearing from departure to destination. The Mercator projection's key property is that rhumb lines appear as straight lines.
Cited:Bowditch Ch. 4 §402