USCG Exam PracticePlotting with variation and deviation (T-V-M-D-C)
When a magnetic compass is fitted aboard a towing vessel, the person directing and controlling the vessel's movement is required to do which of the following?
- ✓ Know and apply variation and deviation where charts have enough detail to enable this correctionCorrect
- B. Apply variation only, as deviation is corrected by the compass adjuster prior to departure
- C. Apply deviation only when operating in areas of known magnetic anomalies
- D. Record compass error in the voyage plan but is not required to apply corrections underway
Why A is correct
33 CFR §164.78(a)(5) requires the person directing and controlling the movement of a towing vessel to know and apply both variation and deviation where a magnetic compass is fitted and where charts or maps have enough detail to enable this type of correction. There is no provision to apply only one component of compass error.
Cited:33 CFR §164.78