A towing light shares the stern light’s color, but its visibility and placement matter under COLREGs

Outline in brief

• Hook: Lights on the water aren’t just for looks; they tell a story.

• Core take: For towing vs stern lights, the correct choice is that the towing light has the same characteristics as the stern light.

• Why that’s true: color and basic visibility rules, plus where it’s placed.

• What really changes: the purpose, the display above the stern light, and what other vessels should watch for.

• Real-world sense-making: how this looks from a skippers’ vantage point and why it matters for safety.

• Quick tips: how to remember the difference without overthinking it.

• Closing thought: lights are a language; once you decode it, the water feels a lot safer.

Toward clearer Deck-to-Deck Communication: The towing light vs the stern light

Let’s start with a simple scene. You’re near a busy harbor as the sun ducks below the horizon. Boats come and go, and a tugboat glows with its white lights at the back. You’re not just looking for pretty colors—you’re reading a signal. The question you might ask in a quiz or in the field is this: what is the characteristic of a towing light compared to a stern light?

The short answer, to align with the line you’ll see on many study guides, is this: It has the same characteristics as the stern light. In other words, the towing light shares the same color (white) and the same basic visibility rules as the stern light. So why do some folks think there’s more to it? That’s where the nuance comes in, and it’s worth unpacking.

Color and basic arc: the familiar backdrop

Both lights are white, and both are part of the standard navigation-light set at the rear of a vessel. You can imagine them as siblings in the same family. The color is the first and most obvious clue: white. If you’ve ever stared at a night scene on the water, you’ve noticed how white lights behave—clean, bright, and easy to pick up against the dark. That consistency is important. It means other vessels can recognize a stern-facing signal in the same way they recognize a towing signal.

In many regulatory descriptions, the towing light is described as sharing the same basic characteristics as the stern light. That’s not to say there’s no difference at all—the purpose and display have their own specifics—but the core attributes you memorize tend to align with the stern light in color and general arc of visibility.

Where the distinction actually lives

Here’s the heart of the matter, and this is where a lot of students pause to map it in their minds. The towing light is used to indicate that a vessel is performing towing operations. That intention matters. It signals to nearby boats, “Heads up, we’re not just cruising—we’re in a tow.” To support that purpose, the towing light is typically displayed above the stern light on the towing vessel. This vertical arrangement is a quick, visual cue: “there’s a towing operation, and it’s active.” In practice, that placement helps other mariners see the term “tow” from a little farther back and a bit to the sides.

So while the color and the basic arc align with the stern light, the broader meaning and the specific display position give the towing light its unique identity on the water. It’s a subtle distinction, but a crucial one for safe navigation.

A practical mental image you can carry on deck

If you want a quick mental picture, here’s a simple way to remember: think of the stern light as the vessel’s rear-facing beacon, signaling general approach from behind. The towing light sits higher, signaling a special operation—towing. They share the white color and the fundamental visibility logic, but the towing light’s placement and implied duty (tow operation) sharpen the message for other vessels.

This is exactly why many mariners say the towing light has “the same characteristics” as the stern light in basic terms, while actually relying on its elevated position to convey a specific action at sea. It isn’t that one light is identical in every technical detail to the other; rather, it’s that the foundational light rules—the color, the rearward orientation, the white spectrum—are aligned, with the towing light adding a clarifying layer through its placement.

Putting it into everyday waterside sense

Think of a tug pushing a barge along a river passage or a vessel drawing another craft. Other boats want to know: is that a simple sailing craft, or is there a tow happening? The towing light helps answer that question quickly, especially at night or in poor visibility. It isn’t about flashy optics; it’s about safety, predictability, and smooth traffic flow.

If you’ve ever watched a harbor from the pier, you might notice how quickly the rhythm of lights communicates intent. The stern light marks the vessel’s tail. The towing light, perched above, quietly adds a layer of meaning—“we’re actively towing.” This is the kind of nuance that makes COLREGs feel less like a checklist and more like a shared language among mariners.

A few quick tips to keep it straight (without overcomplicating things)

• Color check: Both lights are white. If you’re not sure, you’re likely dealing with a different type of signal light. White is the giveaway here.

• Placement cue: The towing light sits above the stern light. If you see two white lights in a vertical line at the rear, that’s the towing configuration serving a towing operation.

• Purpose in view: The stern light covers the typical rearward visibility, while the towing light adds a clear signal that a tow is in progress.

• Arc intuition: The basic visibility arc aligns with the stern light’s framework. The extra edge you notice visually is mostly due to how the two lights are arranged and how far back the vessel is seen in context.

Why these nuances matter in the real world

Navigation is a collaboration. Every vessel on the water relies on clear signals to anticipate what others will do next. A towing operation is a special case because it affects handling, stopping distance, and drift in ways that can surprise other skippers if signals aren’t understood. The towing light’s elevated position helps ensure that the message isn’t lost when waves kick up or when silhouettes blur against city lights.

If you’ve ever found yourself in a dense traffic scene at sea, you know that small cues make a big difference. A single light in a different place can change how you interpret a vessel’s course. By knowing that the towing light shares the same core characteristics as the stern light, you have a reliable reference point. The extra context—the tow status and the up-high placement—gives you the fuller picture.

A quick recap you can carry to sea

• The towing light is white, like the stern light.

• It is used to indicate towing operations.

• It is displayed above the stern light on the towing vessel.

• The light’s basic arc of visibility aligns with the stern light; the key difference is its position and the towing context.

A few friendly reminders for learners and skippers

• Don’t rely on color alone—always check placement. Two white lights in a vertical line at the stern tell a shared story about towing.

• Practice recognizing the signal under different conditions. Night runs, fog, or glare can blur details, but the relative positions tend to stay consistent.

• When in doubt, give extra space. Tow operations often mean the vessel’s handling characteristics are different, so a little extra distance is wise.

Closing thought: read the water as a conversation

Lights are the water’s way of speaking to us. The towing light and stern light are part of a careful vocabulary that keeps things smooth and safe. By remembering that the towing light shares the same color and core features as the stern light, while also noting its higher placement and towing purpose, you develop a practical, instinctive sense for what you’ll encounter on the water.

So next time you’re near a busy channel or a quiet river bend at dusk, look for that familiar white pair at the stern. If you spot the extra light above it, you’re seeing a tow in action. And if you hear that little voice in your head—the one telling you to keep your distance and stay attentive—you’re listening to the water’s best advice: navigation is a shared journey, and clear signals are how we all stay safe together.