When a collision is imminent, change course and speed as needed.

When the sea gets crowded with boats and the horizon becomes a line of potential misunderstandings, what should you do the moment a collision looks likely? If you’ve ever wondered about the exact move that keeps everyone safe, you’re not alone. The answer is practical, decisive, and rooted in a long-standing set of rules that keeps mariners thinking clearly even when the waves are loud with wind and worry.

A quick map of the rulebook’s heartbeat

Collegial as they are, the COLREGs are less about fancy theory and more about real-time action. Rule 8 is the one that says, essentially: if you’re in danger of colliding with another vessel, you must take action to avoid the danger. And you must do it early, and you must do it effectively. In plain terms: alter your course and/or your speed as needed to keep well clear of the other vessel.

Let me explain why changing course and speed is the go-to move

Think of two cars approaching a narrow lane from opposite directions on a highway with blind spots. If one driver simply slows down and hopes the other notices, trouble can still loom. But if both drivers adjust—one veers, the other slows a touch—the path clears and the risk falls away. The same logic applies at sea.

• Immediate impact: A single, proactive adjustment can prevent a collision now, not later. This is not about a dramatic show of force; it’s about making a smooth, timely, well-considered change to your own trajectory.

• Situational flexibility: The exact change depends on what you’re seeing, where you are relative to the other vessel, wind and current, and the other vessel’s course. Sometimes a slight course change is enough; other times you’ll need a more noticeable turn or a bit of speed adjustment to gain the required separation.

• Shared responsibility: You’re not just protecting your own vessel. Your actions influence the other ship’s plan, and good seamanship is about keeping everyone clear.

What about the other options? Why they’re not the heroes in this scenario

• Maintain speed and course: That choice sounds safe in calm moments, but when a collision is imminent, staying the same path is a recipe for contact. The whole point of Rule 8 is to take action to avoid the other vessel, not wait until you’re in a true squeeze.

• Significantly reduce speed: Slowing down can help, but it isn’t always the best lever to avoid a collision—especially in a crossing or overtaking situation where there isn’t enough time just to drift out of the way. You might still end up in a bad position if you misjudge how the other vessel will move.

• Sound the horn continuously: A warning tone is useful for signaling danger, but it doesn’t change the geometry of the situation. Without a real maneuver—changing course or speed—the danger remains, and the warning alone can create confusion in busy traffic.

Anchors away with a practical mindset

When risk appears, the best practice is to act. Quick, deliberate adjustments to your heading and speed give you the best chance to end up well clear. It’s about keeping your vessel’s path out of the other vessel’s way, and doing it before the moment of closest approach. The sooner you start, the more options you have to find a safe solution.

Here’s how that mindset translates on deck

• Lookout first, always: A sharp, clear watch is the foundation. If you miss the other vessel, even the smartest maneuver won’t help you. A good lookout catches the risk early—before it becomes a near miss.

• Assess and decide, then act: Observe, think, and act. You don’t want to be paralyzed by analysis, but you do want to be precise about how your speed and heading will change and what effect that will have on the other vessel’s behavior.

• Communicate when it helps: If there’s any room to coordinate with the other vessel (via VHF or other agreed signals), do it. If both parties know the plan, the risk of misinterpretation drops sharply.

• Keep it simple and safe: A small, clear adjustment is often better than a dramatic, last-second move. The goal isn’t to showcase fancy maneuvers but to secure safe separation.

A real-world sense-check: how these decisions feel on the water

Imagine you’re at a busy harbor entrance. A cargo vessel on your port side isn’t sure which way you’ll go, and your own heading brings you toward a close encounter. The move that satisfies Rule 8 is not a lavish stunt; it’s the clean, purposeful shift in course and a measured tweak to speed that creates a gap. It might be as simple as “turn a degree or two to starboard and ease off a touch,” if that’s what the geometry requires. Or perhaps you’ll need a broader arc if the other vessel’s path is stubborn. Either way, the principle remains the same: you adjust, you gain space, you pass safely.

Guidance you can carry from deck to deck

• Train your gut for early action: The moment you sense a risk of collision, start evaluating your options. Delaying action narrows your choices and increases pressure on your decision-making.

• Practice good seamanship habits: Keep a clean lookout, maintain clear communications, and stay mindful of speed in tight traffic. These habits compound when tension rises.

• Use the tools you’ve got: AIS can help you gauge the other vessel’s likely track, radar can give you distance and closure rates, and an orderly watch keeps you from being surprised by a sudden move.

• Remember the variance: Water, wind, current, and vessel size all tilt the balance. What works in one encounter might need adjustment in another. Flexibility is a strength, not a weakness.

Common questions mariners have (and straight answers)

• Do you always turn to the starboard when avoiding another vessel? Not always. The safest change depends on the other vessel’s course and speed, your own position, and the surrounding traffic. The goal is to create sufficient, safe separation, not to follow a fixed rule.

• Can you slow down a lot instead of turning? Sometimes, yes, but not as a universal fix. If you slow down too much, you can end up stuck in a dangerous line or misjudge the other vessel’s response. It’s about balance—speed and heading together.

• What about signaling? Sound signals are important for warnings and intent, but they don’t replace active maneuvering. Use signals to clarify your actions, then carry them out with a clear change in course or speed.

A weekend-ready checklist for safe decision-making

• Lookout: Are you certain you can see and identify all traffic in your vicinity?

• Predict: Where will that vessel be in 2, 3, or 5 minutes? What’s your best course of action to keep clear?

• Act: Execute the change in course and/or speed as needed. Keep it smooth and controlled.

• Communicate: If there’s a chance to clarify intentions, do it. Then re-check the situation.

• Monitor: After the maneuver, watch how the other vessel responds. Be prepared to adjust again if necessary.

Why this matters beyond the moment

Every time you change course and speed to avoid a collision, you’re practicing the core ethic of seamanship: responsibility for your own vessel and the safety of others. It’s a habit that translates into calmer days at sea, fewer near-misses, and a crew that trusts the navigator’s judgment. The decision to alter course and speed as needed is simple in principle but mighty in impact.

In the end, the rule isn’t about cleverness or bravado. It’s about clear, timely action that protects life, property, and the maritime environment. When a collision looks possible, the best move is the straightforward one: adjust your path, adjust your pace, and keep moving toward safety.

So, the next time you’re out there and a hint of danger appears on the radar, ask yourself a simple question: Can I see a safer path if I nudge my heading or reduce speed just enough to clear the other vessel? If the answer is yes, that’s your cue to act. Change course and speed as needed, and you’ll steer toward safety with confidence—and that’s the mark of strong seamanship.