Chart Navigation & Plotting · Compass Error
The memory aid 'Can Dead Men Vote Twice At Elections' (Compass-Deviation-Magnetic-Variation-True, Add East) is used when converting:
- ATrue to compass
- BCompass to true✓ Correct
- CGyro to magnetic only
- DMagnetic to gyro
Explanation
Reading Compass → Deviation → Magnetic → Variation → True correcting and adding easterly errors converts a compass reading to true. Reversing the ladder (True down to Compass) requires adding westerly errors instead.
Authority: Bowditch, American Practical Navigator (Pub. 9), TVMDC
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