Navigation General · Aids to Navigation — Range Lights
Two range (leading) lights or daymarks are kept in line by the helmsman to:
- AMeasure the tide
- BStay on the centerline of a channel (when the marks are vertically aligned)✓ Correct
- CFind true north
- DEstimate wind
Explanation
A range consists of two marks at different heights and distances; when they appear vertically in line, the vessel is on the charted range line (usually a channel centerline). Opening the marks shows the vessel is off to one side.
Authority: Light List; piloting practice
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