It was a dark and stormy night – really. My friend Hayden, my teen-age son Alan, and I were delivering a 25-foot trimaran down the length of Chesapeake Bay, riding a norther and determined to do it in one jump. About 10:30 p.m., we were off Calvert Cliffs, doing about 8 knots in intermittent rain. Alan was on the helm, Hayden was in the after cabin, and I had just climbed into the forward bunk when Alan said, “I don’t understand these lights.”

COAST GUARDFigure 1: Lights for a power vessel less than 50 metersHayden and I stuck our heads out our respective hatches and both shouted in unison, “Hard Right Rudder!”

What we saw was a red light right in front of us, about 30º up, and a white light to its right and higher. Alan, who had never heard that command before, jammed the tiller over and we shot off to the right. Other than its running lights, the steamer we almost hit was invisible in the dark and rain. Had we not veered, our little trimaran would have been smashed to kindling and no one else would even have noticed.

It is important for anyone operating a boat at night to be able to recognize and understand the lights they see. Lights for nighttime operation, commonly referred to as running lights, are required for every type of craft larger than a rowboat or canoe. In general, the lights specified for Inland waters are the same as for International waters. The requirements can be found in Navigation Rules, which is published by the Coast Guard and available at many marine supply stores, as well as online (see link below).COAST GUARDFigure 2: Lights for a vessel less than 7 meters whose maximum speed is less than 7 knots.

Lighting can be a confusing topic, because different vessels conducting different activities each have a separate lighting configuration. What we have done here is cover some of the basics, along with illustrations to depict what we describe. It is not a substitute for reading and learning the Rules, but it may serve as an introduction.

BASIC RUNNING LIGHTS

All powered vessels use the same basic running lights, which are employed when the vessel is underway between sunset and sunrise – or any other time they might be necessary. The basic lights consist of a white “masthead” light (it doesn’t have to be at the top of the mast, just elevated above the other lights) that shows from dead ahead to 22.5º abaft the beam on both sides, or 225º total; a red light showing from dead ahead to 22.5º abaft the beam to port; a green light showing from dead ahead to 22.5º abaft the beam to starboard; and a white stern light showing from dead aft to 67.5º on both sides, or 135º total (See Figure 1).

COAST GUARDFigure 3: Lights for a vessel longer than 50 metersThis means that you will see some kind of light no matter from any angle you view the vessel. From aft you will see a single white light. From abeam you will see a colored light and a white light above it. And from dead ahead you will see both colored lights and a white light above and between them.

There are variations for small vessels. A powered vessel less than 7 meters (23 feet) that can go no faster than 7 knots need only show an all-around white light with 360º visibility, though it may also show side lights (See Figure 2). Also, vessels less than 12 meters (39.4 feet) may use a combination red and green light on the bow.

Vessels longer than 50 meters (164 feet) must also carry a second masthead light aft of and higher than the forward masthead light (see Figure 3). These two white lights allow you to judge its direction before you see the colored side lights.