Chart Navigation & Plotting · Chart Symbols — Compass Rose
The variation printed inside a chart's compass rose is given for a stated year, so before use it must be:
- AUsed unchanged regardless of date
- BApplied only during daylight
- CReplaced by the deviation
- DCorrected for the annual increase or decrease to bring it to the current year✓ Correct
Explanation
The compass rose states variation for a specific year together with an annual change (increasing or decreasing). Multiply the annual change by the years elapsed and apply it to obtain the variation for the current year.
Authority: NOAA charts; Bowditch (Pub. No. 9)
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