Rules of the Road · Light Arcs — Masthead
A masthead light shows an unbroken arc of the horizon of:
- A112.5 degrees
- B135 degrees
- C225 degrees✓ Correct
- D360 degrees
Explanation
A masthead light is white, shown over the fore-and-aft centerline through 225° — from right ahead to 22.5° abaft the beam on each side.
Authority: COLREGS/Navigation Rules, Rule 21(a)
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