Rule 32: How navigation lights reveal a vessel’s status in darkness or poor visibility

Lights on the water aren’t just pretty. They’re a language. When you’re out after dark or in fog, those tiny glows tell you who you’re sharing the water with and what they’re up to. Rule 32 of the COLREGs (the Rules of the Road) makes this language official: displaying lights is primarily about indicating the status of other vessels at night or in poor visibility. simple as that, yet incredibly powerful for safety.

Let me explain what that means in real life.

What Rule 32 really does

Think of Rule 32 as the “communication protocol” for vessels in the dark. The lights a boat shows aren’t decorative—they’re a signal about the vessel’s size, what it’s doing, and how you should respond. When you can see those lights clearly, you can quickly decide who should give way, who should stand on, and what action might be required to avoid a collision.

Here’s the core idea, without getting lost in the jargon: lights tell you the status. They help you identify presence, type, and activity. That quick read is what keeps you from taking a wrong turn in the night and bumping into someone else’s plans.

How the lights convey status

The basic color pattern you’re likely to notice on most vessels goes beyond the pretty glow. It’s about what’s underway, what’s anchored, or what kind of work the vessel is doing. A few mental checkpoints help:

• Red and green sidelights: These show the vessel’s position relative to you. If you’re approaching from the side, the color you see tells you which side you’re looking at. It also hints at whether the other boat is steering toward you or away from you.

• A white light forward and another white light aft: These identify a vessel that is under way. The combination gives you a clear sense of its length and direction at the moment you first glimpse it.

• Special or additional lights: Some vessels use flashing lights or specific configurations to signal particular activities (like towing, fishing, or restricted maneuverability). In those cases, the extra lights are telling you, “phrase it quickly, I’m doing something unusual.”

The key takeaway is this: the lights aren’t just about the vessel’s position; they’re about its status and intended movement. When you interpret those signals correctly, you know whether to slow down, alter course, or keep your current plan.

Why this matters for night navigation

Navigation at night is all about reducing uncertainty. The state of visibility—fog, rain, or just a moonless sky—adds a layer of risk. Lights cut through that fog of uncertainty by giving you a reliable cue about another vessel’s behavior. You don’t need perfect sightlines to respect the Rule 32 signal; you just need to recognize what the other boat’s lights are trying to tell you.

A quick, practical way to think about it

• If you see a vessel’s green sidelight ahead on your right, you know where its starboard side is and you can gauge whether it’s crossing your path from the left or right.

• If you spot white forward and white aft lights that are clearly visible, you’re looking at a vessel that’s actively moving in some direction, which means you should be aware of its potential course changes.

• If you see unusual or flashing lights, you can infer the vessel isn’t behaving like a standard power-driven craft. It may be engaged in something requiring extra care from you, and you’ll adjust your actions accordingly.

A couple of real-life moments where Rule 32 shines

• Night crossing on a busy river: One vessel shows the standard white forward light and a stern light. On your radar, you can see where it’s headed and how quickly it’s moving. You adjust speed and course so you don’t end up on a collision course, even if your visibility is limited.

• Poor visibility in a fog bank: A boat far off to your starboard glows with red and green sidelights but no obvious stern light. The colors tell you its relative position and motion, which helps you decide whether to give way or hold your course.

Where the common confusion creeps in

People often mix up the purpose of lights with other signals. For example, lights can indicate distress in emergencies—but that’s not the primary function of Rule 32. Distress signals are a separate category of safety signaling. Likewise, lights aren’t meant to “prevent engine trouble” or directly convey every intention of the vessel’s crew. The lights are mainly about status and visibility, a quick read that informs safe maneuvering.

A small mental model you can carry

• See light, assess status: Red/Green = position and type; White forward/astern = underway status; Special signals = unusual or restricted maneuverability.

• Then decide: who should yield? What’s your best escape route? How can you keep your own vessel’s path predictable to others?

How to apply this on the water (a concise checklist)

• Do a quick scan for color and placement of lights as soon as you spot something unfamiliar.

• Determine whether the other vessel is underway or anchored (based on the light pattern) and gauge its likely heading.

• Compare your course with the other vessel’s indicated status. If in doubt, reduce speed and increase your lookout. It’s often better to err on the side of caution.

• Use established right-of-way rules in tandem with what you’ve inferred from the lights. Rule 32 is the first layer of safety; the actual maneuvering rules are the follow-up.

A nod to the broader picture

Rule 32 sits at the heart of maritime safety, but it’s not a stand-alone rule. It works in concert with the other Rules of the Road that govern crossing situations, overtaking, and head-on scenarios. The beauty of the system is how the lights give you a shared, interpretable vocabulary that helps mariners from different backgrounds respond in a predictable, safe way.

Why you’ll appreciate Rule 32 on the water

If you’ve ever been in a dim harbor or rolled through a river bend after sunset, you know how quickly misreads can happen. Rule 32 provides a simple, universal cue: lights mean status. That one concept helps you avoid near-misses and keeps everyone in the traffic pattern moving smoothly and safely.

A few notes on accuracy and nuance

• The exact light configurations can vary with vessel type and operating conditions. The general principle remains the same: lights communicate status and help determine safe action.

• The emphasis is on nighttime and poor visibility. In clear daylight, eyes and sound signals often fill in the gaps, but at night, lights are the primary communicators.

• Always pair your light-reading with other cues such as radar returns, AIS data if available, and the vessel’s apparent behavior. A clear, multi-sensor read is the safest approach.

Closing thought

The sea is a big, open street with a lot of moving parts. Rule 32 reminds us that good navigation starts with seeing—really seeing—the other vessels and understanding what they’re telling us with their lights. When you can read those signals quickly and correctly, you’re less likely to encounter surprises and more likely to reach your destination safely.

If you’re curious about how lights map to specific vessel activities, or you want a calmer, more intuitive framework for quick night reads, keep this idea in your pocket: lights are status, status guides action. That simple rule can be the difference between a smooth ride and a tense close call.

In the end, it’s all about clarity on the water. The lights aren’t just decoration; they’re a shared language that keeps mariners moving in harmony, even when the night grows thick.