USCG Exam PracticePassing distance and CPA from chart plot
When determining whether a risk of collision exists, which method is described as the canonical approach for an approaching vessel observed visually?
- ✓ Observing whether compass bearings remain constant while range is decreasingCorrect
- B. Comparing the vessel's speed over ground to its speed through the water
- C. Plotting successive radar ranges at fixed time intervals
- D. Measuring the vessel's relative bearing from the bow at two-minute intervals
Why A is correct
Bowditch Ch. 7 §704 states that compass bearings of an approaching vessel are the canonical method of detecting risk of collision, and that if the bearing remains constant and range is decreasing (CBDR), risk of collision exists. Relative bearings from the bow are not the same as compass bearings and can be misleading when own ship is turning.
Cited:Bowditch Ch. 7 §704