Know Your Nav Lights

Get familiar with the “Rules of the Road,” and make sure your lights meet the requirements.


It’s a no-brainer that proper navigational lighting is crucial for safe and legal operation at night or during times of reduced visibility. So why do so many vessels I inspect as a marine surveyor fail to comply with mandated navigational lighting requirements? I’d estimate the number is as high as 30 percent (or more), which is an appalling rate when it comes to safety-related equipment. Imagine if your life jackets or fire extinguishers only worked 70 percent of time when they were needed.

Many problems I see are maintenance or owner-induced issues — burned-out bulbs, broken wires, blocked lights — but an alarming number are improper installations by the manufacturer. It appears many builders either do not have a good understanding of the navigation rules governing installations or they shoot for (and miss) the bare minimum requirements, often at the expense of the end user.

Regardless of what the manufacturer did (or didn’t) do, it’s imperative to remember that when it comes to navigational lighting, it’s an owner’s responsibility to ensure his boat complies with the rules. Here’s how to make sure your boat is ready for the nightlife.

The Basics

All boats must have the ability to display required navigation lights while operating at night and during times of reduced or restricted visibility such as fog or heavy rain. Vessels 16 feet in length or greater must have properly installed navigation lights and an anchor light, which must be operable separate from the running lights.

Required navigation light configurations are based on a number of factors, such as a vessel’s length, method of propulsion or any special activity it’s engaged in, such as trawling or towing. The type, arc and color of navigation lights allow boaters to determine a vessel’s size, propulsion, whether it’s anchored or moving, and, if it’s moving, its course. For example, if you look over your bow and see a red light followed by a white light, you can assume the boat is crossing your path from starboard to port and, depending on distance, that it has the right of way. A single white light visible 360 degrees, on the other hand, indicates an anchored vessel.

The first step in determining if your vessel is compliant is to consult a copy of U.S. Coast Guard COMDTINST M16672.2D, aka the “Rules of the Road.” You can purchase a copy or view it for free online at


Once you’ve consulted the Rules of the Road and determined your navigation lights meet the requirements, next up is a physical inspection to make sure they’re installed and operating properly. Start by turning on your running lights and then your anchor light, verifying in turn that each powers up and meets the visibility requirements mentioned in the Rules of the Road.

Look for issues such as the placement of equipment (e.g., dinghies, fenders) that could block visibility, burned-out bulbs and poor lighting installations. A good example of the latter would be a masthead light that effectively blinds a skipper who’s operating the vessel from the upper helm or flybridge. Assume nothing and keep your eyes open for the unexpected, such as side light lenses (red port, green starboard) that are reversed — a problem I’ve seen after lights have been replaced by well-meaning owners.

Sailboat owners may find it easier to verify the operation of mast-mounted navigation and anchor lights at night from the dock, when they’re more easily visible.

Next, take a good look at the lights themselves. Are they burning brightly or are they dim? Dimness can be caused by UV damage or “frosting” of the lens, installation of the wrong type of bulb, or a poor quality light. Dirty lenses or corroded electrical contacts and switches can also cause problems.

Distance visibility — how far navigational lights can be seen — is crucial and can easily be a case where meeting the letter of the law doesn’t necessarily mean the spirit of the law has been satisfied. I’ve seen installations that meet the minimum requirements under perfect conditions — clear weather, minimal wave action — but fail miserably in less-than-ideal conditions, the very times a boat needs to be seen most. Problems range from poor location of the navigation lights (flush-mounted sidelights in the hull below the rubrail are a good example of this) to the lights themselves, which are often too small or simply pieces of junk.

Don’t be afraid to relocate factory-installed navigation lights to better comply with the requirements or replace them with brighter, more robust units. LED (light-emitting diode) fixtures have become a popular choice in recent years due to advantages such as longer life (up to 100,000 hours in some cases), less power consumption, sealed construction (eliminating corrosion) and non-susceptibility to damage from shock or vibration. Do not, however, simply swap your incandescent navigation light bulbs with LED replacements. Navigation light fixtures are approved for use as a unit (i.e., bulb and fixture together), so simply swapping out the bulb of your current fixture does not mean the new combination will comply.

Once you’ve verified everything is in good working order, record the types of bulbs required for all navigation lights and ensure you have plenty of spares on board.

Finally, include a check on the operation of all navigation lights as part of a pre-departure checklist. It only takes a moment, and you’ll be doing yourself (and everyone else on the water) a favor.

Downside of Decoration


Boat owners just love lots of pretty lights, but by rule decorative light installations can’t be mistaken for navigation lights and they cannot impair the visibility or the distinctive character of approved and properly placed navigation lights. They also can’t interfere with the ability to maintain a proper lookout. Haphazard installation of additional lighting must be avoided and violations (resulting in fines or worse) can be cited if the mood lights installed on your rig can be construed as a light required by the Rules for another vessel. For example, blue underwater LED lights can appear to flash if wave action is present, giving the appearance of a flashing blue light that only law enforcement vessels are authorized to use.