5 navigation lights for your boat

Navigation lights on your boat serve three purposes:

Alert other boats of your presence and relative location.
Tell other boats something about your vessel’s size, speed, course, and type (sail or power).
Enable you to apply the Navigation Rules properly.

If you operate your boat at night, you should know what the various lights signify, especially on tugs, barges, and large vessels. You are required to equip your boat with the correct navigation lights. You also must display them when operating between sunset and sunrise and during periods of reduced visibility. Lights that satisfy the International Rules also meet Inland Rules requirements.

Types of navigation lights

There are five types of vessel navigational lights. The distance at which the lights must be visible varies with the length of the boat.

Masthead lights are white lights placed over the vessel’s fore and aft centerline. Unbroken over a 225-degree arc of the horizon, the light shows from dead ahead to 22.5 degrees abaft the beam (behind the beam) on either side of the vessel. Masthead lights are used only when a boat is under power. Vessels less than 12 meters (39 feet) in length may combine the masthead light with the stern light to provide 360-degree visibility.

All-around lights are visible 360 degrees around the horizon. They may be white, red, green or yellow, depending on their function.

Sidelights are a green light on the starboard side and a red light on the port side each showing an unbroken light over a 112.5-degree arc of the horizon and fixed to show the light from dead ahead to 22.5 degrees abaft the beam on its respective side. On boats less than 20 meters (65 feet) long, the sidelights can be combined in one lantern (combination light) carried on the vessel’s fore and aft centerline.

Stern lights are white lights that shine 135 degrees aft (67.5 degrees from directly astern and to each side of the vessel). When you see the stern light of another vessel, you will not see its sidelights or masthead light.

Towing lights are yellow lights with the same characteristics as stern lights mounted at the stern on towing vessels. A towing vessel is a power-driven vessel towing astern, alongside or pushing ahead.