Chart Navigation & Plotting · Compass — Uncorrecting to Compass

Your true course is 100°. Variation is 12°E and deviation is 4°W. What compass course do you steer?

Explanation

Uncorrecting (true to compass): subtract easterly, add westerly. Magnetic = 100° − 12°E (var) = 088°. Compass = 088° + 4°W (dev) = 092°.

Authority: Bowditch (Pub. No. 9), Compass Error

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