What is the coverage area of a masthead light?

The coverage area of a masthead light is 225 degrees. A masthead light is an essential navigation light typically found on vessels over 12 meters in length. It serves to indicate the presence of the vessel to others when underway at night or in low visibility conditions.

The light is positioned at the highest point on the vessel and is designed to be visible over significant distances, projecting its beam primarily forward and to the sides. The 225-degree coverage is calculated to extend from directly in front of the vessel, sweeping outward to just behind the beam of the vessel, ensuring effective visibility to other vessels approaching from the front and side angles.

This configuration helps to maintain a clear understanding of the vessel's heading and assists other vessels in determining their position relative to the masthead light. The remaining 135 degrees behind the masthead light is left intentionally unlit as vessels are not required to show a masthead light astern.