USCG Exam PracticePlotting with variation and deviation (T-V-M-D-C)
A vessel observes a lighthouse bearing 045° by compass. Deviation on the vessel's current heading is 3°W and variation for the area is 9°W. What is the true bearing of the lighthouse?
- ✓ 033°TCorrect
- B. 057°T
- C. 051°T
- D. 039°T
Why A is correct
Correcting compass bearing to true: add easterly, subtract westerly. 045° − 3°W deviation = 042° magnetic; 042° − 9°W variation = 033°T. Both errors are westerly so both are subtracted when correcting toward true.
Cited:Bowditch Ch. 6 §602