Shot in the Dark
Don't underestimate the importance of navigation lights make sure yours are in proper working order to avoid potential danger.
by Chris Caswell
February 1, 2002
Have you ever looked at your boat from a distance at night? If you're like most skippers, you
haven't, so it might be very instructive to leave your navigation lights on while you take a walk
around the harbor. It may come as a shock that your boat is nearly invisible. Add in bad weather,
and then imagine being on the bridge of a ship. Could your boat be seen? Probably not.
Many navigation lights installed by boat manufacturers are laughable at best, and dangerous
at worst. In some cases, the bulbs are so weak you can barely see them from 100 feet away. In other
instances, the lights are mounted incorrectly, which will cause you to appear invisible, or cause
other skippers to misinterpret the direction you're traveling.
When you're relying on your navigation lights to prevent collisions at night, make
absolutely sure you can be seen. A good rule of thumb for navigation lights is: If you can't read a
newspaper by them at a distance of five feet, they aren't worth anything on a dark and rainy night.
First of all, let's look at the minimum legal requirements for navigation lights on small
powerboats. Powerboats measuring less than 39 feet must show sidelights of red (port) and green
(starboard) from dead ahead to 112.5 degrees aft on each side, as well as a white all-around light
visible for 360 degrees. The colored sidelights must be visible for at least one nautical mile,
while the white light must be visible for two nautical miles.
On most small powerboats, this translates to a so-called 'bi-color' light on the bow that
combines both the sidelights into a single fitting with one bulb, plus a white light mounted on a
staff at the stern or on top of a radar arch or hardtop.
The first step in improving your safety at night is to make sure your lights are correctly
mounted. In many cases, the bi-color light may be aimed incorrectly so the red or green lights
'leak' to the wrong side. Only when you are headed directly toward another vessel should both the
red and green lights be visible. Otherwise, you're giving the other skipper bad information, and he
may take action that could jeopardize your boat.
It's not unheard of to see a powerboat on which both sidelights are visible from as far as
20 degrees to each side. Bi-color lights save the boatbuilder some money by simplifying
installation, but you may want to replace them with sidelights that are clearly separated and
distinct.
On runabouts, the all-around light is often mounted on a post at the stern, and under ideal
conditions, it may meet the legal requirements. But if you put up your Bimini top and cockpit
enclosure, you might be blocking the white light from view forward.
The second step is to check the visibility range. In this case, your concern is likely to be
the colored sidelights, since the colored lenses reduce the apparent power of your bulbs. The white
stern light usually provides ample visibility, but in many cases, you don't have to walk a mile
away from your boat to know those little red and green pinpoints probably won't meet the one
nautical mile requirement. Even if they did meet that minimum, think about the crew on the bridge
of a big ship, peering through a spray-encrusted pilothouse window. Can they see you and your
family clearly?
If your answer to any of the questions has been 'no,' then it's time to replace your
navigation lights with some that will make you almost impossible to miss. Just as some people
replace their car horns with much more powerful truck horns, you can give other skippers the
impression you're of a size to be reckoned with just by having powerful navigation lights.
There are a wide variety of lights available in marine hardware stores, and because each
boat has different mounting opportunities, it's hard to say which is best. If you have a bi-color
light mounted on the deck at the bow, you might want to replace it with individual sidelights
mounted on your pulpit, which not only provide better separation, but also additional height for
visibility in choppy seas.
It's surprisingly easy to mount lights to a bow pulpit using the ready-made brackets that
clamp to the rails or stanchion tubing. Once aligned properly, you then run the wiring down inside
the hollow tubing and through the deck.
When buying new sidelights, consider two things: wattage and lens. Just as a flashlight
relies on a powerful bulb to produce a bright light, you'll want to get the most powerful bulb you
can. Bulbs range from five up to 25 watts in power for 12-volt systems, with both powerful halogen
and conventional filament bulbs. Lighthouses amplify the power of their lights by using fresnel
lenses that focus the beam. More sophisticated navigation light lenses also provide this effect,
whereas less expensive lights rely on plain plastic lenses.
Whether you've installed new navigation lights or are using those that came with your boat,
remember to include them as part of your regular maintenance program. Always carry spare bulbs of
the proper size and power. Most navigation lights are sealed against moisture, but be sure the
rubber or foam gasket is in good condition. If you see condensation inside the lights, you know you
have a leak. Spray the electrical connection for the bulb with corrosion protection such as WD-40
or Corrosion Block, and if there is a metal reflector inside the light, polish it to a shine.
Underway at night, you can usually see the colored glow from each of your bow lights, but if not,
check to make sure both are working. After all, navigation lights are your first line of defense
when using your boat at night. Make sure they're powerful, and keep them in good condition.