Light Up The Night

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

By Daniel Rutherford
Published: July 2014

Photo of aftermath of a collision between a sailboat and a powerboat
Photo: Petty Officer Jennifer Williamson, USCG
The aftermath of a collision between a sailboat and a powerboat
seven miles east of Bethany Beach, Delaware in July 2012.

Let's consider a scenario for a minute. You're heading out across the lake for a night of fishing. You have your navigation lights on. You are at the wheel and you have one of your crew members watching the horizon for any signs of vessels ahead. It's a big lake and it's dark, very dark. Perhaps you slow down a bit, but there is no "restricted visibility" so you are still moving quickly. Suddenly, out of nowhere, you strike another vessel and two people are killed. What went wrong?

This scenario actually happened, one of many tragedies I have investigated as a marine surveyor specializing in accident investigation and reconstruction. In this case, the boat that was hit was drifting, motor off, lights off, in the middle of the lake. That's right, no lights. They were off to make it easier to gaze up at the stars. That simple mistake turned into a tragedy. Many of the cases involving collisions at night that I have investigated and that result in serious injuries or even deaths could have been prevented with the correct navigation lights used properly.

COLREGS And Night Navigation

The International Regulations for Preventing Collisions at Sea (COLREGS) is akin to the Bible when it comes to safety at sea and assessing the risk of collision. The COLREGS supply us with a well-tested set of rules to live by, including those governing navigation lights. If you, as a fellow boater, haven't read the COLREGS — not a very difficult or time-consuming process — please do so before you hit the water this season, for my sake, as well as your own.

I hope we all know the basic "Rules of the Road" by now. For instance, if you and another vessel are approaching each other and are "in sight of one another", the boat forward of you and to starboard is the "privileged vessel", which makes you the "burdened vessel" in a collision scenario — you must keep out of their way. Conversely, if you have a vessel ahead of you to port, you are the "privileged vessel" and they are the "burdened vessel." These common situations are easy to see during daylight. But in the dark, the only way to see a boat and tell what direction it is moving is by its navigation lights. COLREGS define what navigation lights must be used at night and in restricted visibility so the same collision avoidance procedures can be taken.

COLREGS Part C - Lights and Shapes defines the lights and shapes that must be carried by different vessels in different conditions. First and foremost, the "Rules of this part shall be complied with in all weathers" from "sunset to sunrise" and "during such times no other lights shall be exhibited." The COLREGS even go so far as to say that "The lights prescribed by these Rules shall, if carried, also be exhibited from sunrise to sunset in restricted visibility." Bottom line? If it's hard to see, your navigation lights should be on.

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Nav Light Resources

US Coast Guard Navigation Center. Includes all COLREGs, searchable by subject and with flash cards for practice.

BoatUS Foundation Online Course Animations. Click on the different animations to see if you'd know which type of boat you were seeing based only on the lights.