Light Up The Night

The right navigation lights are essential to safe piloting after dark.

By Daniel Rutherford
Published: July 2014

Illustration of Navigation Light Requirements For Boats Over 16 Feet
West Marine
Navigation Light Requirements For Boats Over 16 Feet

Let's return to the situation we started with — the boat floating on the lake with no lights in the dark. This example helps to illustrate the COLREGS as an intertwined set of rules. Was the drifting vessel (motor off, not anchored) a vessel "underway"? Were they required to "post a lookout" per the COLREGS? Were they required to "take action to avoid collision"? Were they required to display their navigation lights? The answer is "all of the above." If they had taken the required steps, it's likely that there would have been no collision and two lives would have been spared. Unlike cars that need headlights to see, as mariners we count on navigation lights to allow us to be seen.

Part C — Lights and Shapes not only defines when we should be displaying our navigation lights, but it also defines the types of lights, placement of the lights, colors of the lights, and intensity of the lights. For instance, if I were to ask you where your masthead light was, you might say, "At the top of my mast." Well, you might be wrong. That light is probably your all-round light that you use when you're anchored. Your masthead light, for those sailors in the crowd, is the light on the forward side of your mast that should show an unbroken white light over an arc of 225 degrees. For powerboaters, your masthead light is the same 225 degree arc carried probably on the forward side of your flybridge or on a short staff under your all-round light. Boats under 12 meters (about 40 feet) can carry one all-around white light that serves as both masthead and stern light. Power-driven vessels (which also means sailboats when motoring) must display this light when underway.

Photo of an obsurred side light on bass boat
Photo: Daniel Rutherford
The trolling motor mounted here almost completely blocks the green sidelight, rendering it useless.

The red and green lights carried forward are called sidelights. Sidelights each have an arc of 112.5 degrees "so fixed as to show the light right ahead to 22.5 degrees abaft the beam on its respective side." Notice that both lights together cover an arc of — you guessed it — 225 degrees. When you combine your sidelights with your masthead light, an approaching vessel from forward of 112.5 degrees will see either a red light with white above it (if approaching from the port side) or a green with a white above it (if approaching from the starboard side). If you see red, you're likely the burdened vessel, and if you see green you're likely the privileged vessel, just as if you could be seen in daylight.

Navigation Light Mishaps

So what can go wrong with navigation lights? How about a combination red/green sidelight on the bow that is obscured by an anchor hanging off the bow rail? Or a combination bow light that was properly mounted on the bow of a bass boat by the manufacturer, only to have the dealer install a trolling motor bracket that blocked the starboard side of the light? How about sidelights that were installed on the radius of the deck of a boat so that the arc of visibility for the lights were at 45-degree angles rather than across the horizon? These are all real examples that resulted in tragic accidents.

When approaching a vessel from a direction more than 22.5 degrees abaft her beam (from astern), you should see only one white light, the stern light, which makes you the burdened vessel. Stern lights cover the other 135-degree arc that sidelights don't — you can't see both stern lights and sidelights if they are properly mounted. But what if the stern light is blocked by a man-overboard module (MOM) or Horseshoe/Type IV throwable device, or laundry drying on the rail? That one obscured light, if it results in a collision, might cost your life or someone else's.

| 1 | 2 | 3 | Next