Masthead light
A white light placed over the fore-and-after centerline of the vessel, showing an unbroken light over an arc of 225 degrees, from dead ahead to 22.5 degrees abaft (behind) the beam on both sides of the vessel.
On boats less than 12 meters (39.4 feet) in length, the masthead light may be off the fore-and-aft centerline, but must be as close to it as possible.
The term "masthead light" is something of a misnomer. More often than not, this light is not at the top of the mast. On motorboats, it is often on a short staff at the top of the cabin. On sailboats, it is usually part way up the mast, and called the "steaming light". Another light, the anchor light, is usually at the masthead.
The following diagram shows typical lighting patterns that you will see on power vessels under 12 meters. All of the following light patterns are legal, and there is no preferred pattern.
Anchor Lights
A common Navigation light that you will see near harbors or popular cruising destinations is the anchor light. The anchor light is an all-around light that must be visible for 2 miles in any direction. No other navigation lights should be on while at anchor.
Types of Lights
This style of masthead light has 2 bulbs. If a stern light is affixed to the vessel, it is wired so that only the front bulb is lit with the nav light switch on the 'on' position.
When the switch is moved to the 'anchor' position, the stern light is extinguished and both bulbs on the mast light are lit.
If the vessel does not have a stern light, this light is wired to display both bulbs lit in both the nav and anchor positions.
Most of our vessels do not have stern lights because they are outboard powered. A typical transom mounted stern light would be partially hidden by the outboard making visibility and identification difficult at night.
This is why our vessels typical incorporate an all-around light which serves the purpose of a steaming light and an anchor light in one unit.
