Chart Navigation & Plotting · Compass & Course
When converting a true course to a compass course, westerly variation and deviation are:
- ASubtracted
- BAdded✓ Correct
- CIgnored
- DDoubled
Explanation
Going from true to compass (down the TVMDC sequence) you 'add west.' Westerly variation and deviation are added; easterly errors are subtracted. The mnemonic 'True Virgins Make Dull Companions — Add Whiskey' tracks the order and the add-west rule.
Authority: Bowditch, Pub. No. 9 (compass conversion)
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