Masthead Light

A white navigation light showing over the forward sector of a vessel.

Despite its name, a masthead light need not be positioned at the physical top of a mast. It is carried over the vessel’s fore-and-aft centreline and shows from directly ahead to a specified distance abaft the beam on each side.

It forms part of the navigation-light display for a power-driven vessel underway, with the exact number, position and visible range depending on the vessel and applicable requirements. It must not be confused with an all-round white light, whose arc and uses are different.