Rules of the Road · Light Arcs — Sternlight
A sternlight shows an unbroken arc of the horizon of 135 degrees, fixed to show:
- AFrom right ahead to abeam on each side
- BAll round
- CFrom right astern to 67.5 degrees on each side✓ Correct
- D112.5 degrees on the starboard side only
Explanation
The white sternlight covers 135° — 67.5° on each side from right astern. Combined with the 225° masthead arc this gives full 360° coverage.
Authority: COLREGS/Navigation Rules, Rule 21(c)
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