USCG Exam PracticeCompass variation and deviation; T-V-M-D-C
A navigator needs to steer a true course of 215°T. Local variation is 7°W and compass deviation on that heading is 4°E. What compass course should the helmsman steer?
- A. 204°C
- ✓ 218°CCorrect
- C. 212°C
- D. 226°C
Why B is correct
Working from true to compass (reversing T-V-M-D-C): 215°T + 7°W variation = 222° Magnetic; 222° Magnetic – 4°E deviation = 218°C. When converting from true toward compass, west variation is added and east deviation is subtracted. 33 CFR §164.78(a)(5) requires the operator to know and apply variation and deviation.
Cited:33 CFR §164.78