Rule 4 clarifies the crew's duty to avoid collisions through lookout, safe speed, and precise maneuvering

Rule 4: The Collision-Avoidance Cornerstone You Can Really Trust

When people talk about the COLREGs, Rule 4 doesn’t sound flashy. It’s not about clever maneuvers on a calm morning. It’s the safety backbone of every voyage—the rule that sets the bar for how a crew should behave to keep ships, crews, and cargo out of harm’s way. If you’re wondering what the responsibility of crew members under Rule 4 is, the simple answer is this: to ensure the vessel’s obligations to avoid collisions.

Let me explain why that matters in real life, not just on a checklist. On the water, danger often hides in plain sight: a crossing vessel that seems to be a mile away until it isn’t, an approaching head-on sequence that tightens faster than you expect, or a slower-moving ship that looms in your blind spot as dusk settles. Rule 4 doesn’t rely on luck. It puts the duty squarely on the crew to stay vigilant, deliberate, and ready to act.

What Rule 4 really prescribes

Here’s the thing—Rule 4 isn’t a single action. It’s a field manual for attention, judgment, and teamwork. The rule anchors several core obligations that every vessel must uphold, all with one goal: avoid collisions. These duties are not optional; they guide how the crew should think, see, and move on the water.

• Maintain a proper lookout: This isn’t a passive glance over the rail. It means listening for signals, watching for other ships, reading lights and shapes, and using every tool at hand. The lookout is a constant process, not a momentary check.

• Proceed at a safe speed: Speed isn’t just a number. It’s about your ability to react in time if something unexpected appears. A safe speed gives you enough space and time to maneuver without losing control of the situation.

• Use all available means: Radar, AIS, VHF, echo sounders, visual cues—the whole toolbox. If something changes, you’re supposed to use every instrument and method to understand what’s happening and to communicate clearly with others.

• Maneuver to avoid collision: If risk exists, the crew must be ready to alter course or speed. The goal isn’t to win a contest but to keep the route clear and predictable for everyone sharing the water.

• Communicate effectively: Bright lights, sound signals, radio calls—clear communication helps other vessels understand your intentions, which is essential when decisions must be made quickly.

• Document and follow through: Decisions aren’t just made; they’re carried out. The crew should verify that actions are executed and that the situation stabilizes.

A crew-centered view: who’s involved and why it matters

Rule 4 isn’t a solo directive; it’s a shared responsibility across the bridge team. The master or skipper holds the moral and legal duty, but a ship runs on the joint effort of officers, lookouts, engineers, and deck hands. The whole crew must align on the same goal: a safe passage.

• The lookout, often a dedicated role, keeps watch of the traffic, weather, and visibility. Their job is to spot potential conflicts before they become urgent.

• The officer of the watch translates what the lookout sees into actionable decisions. They weigh speed, bearing, and distance, and they decide when to adjust course or speed.

• The bridge team, including the master, coordinates the response and communicates clearly with all hands to ensure the maneuver is executed smoothly.

• The hull and engine departments support by ensuring that the vessel can respond promptly—propulsion, steering, and stability are critical when rapid changes are needed.

You don’t need to be a fancy theorist to get this right. It’s about staying alert, using the tools, and speaking up when something doesn’t look right. It’s also about recognizing that the water is a living, changing environment. What feels safe at one moment can become risky in the next due to wind shifts, current, or a crowded traffic lane.

Common situations and how Rule 4 guides them

Let’s walk through a few everyday marine scenarios to ground Rule 4 in reality. You’ll see how the same rule applies whether you’re in a busy harbor, a narrow channel, or open sea.

• Crossing situations: Picture two vessels approaching at right angles. The vessel on the port side should normally give way, but the crew must verify with radar and AIS, communicate intentions, and adjust speed or course well before a potential clash. The lookout should continuously monitor both vessels, and the maneuver should be executed calmly and predictably.

• Head-on risks: Two ships traveling toward each other require both to alter course to starboard (to pass to the port side, relative to each vessel). Clear, early communication helps avoid last-minute surprises. If visibility is poor, the expectation is heightened vigilance and more conservative speeds.

• Overtaking: When a vessel approaches from behind, the overtaker must keep clear and avoid passing in a manner that interferes with the other vessel’s intended path. The vessel being overtaken should maintain course and speed unless it’s clearly necessary to take action for safety.

In every case, Rule 4 isn’t about a dramatic last-second save. It’s about a steady, predictable approach—watch, assess, and act in plenty of time. That steady approach is what prevents near-misses from becoming real accidents.

Tools that help the crew stay true to Rule 4

Today’s ships aren’t flying blind. They’re equipped with a suite of aids that support Rule 4’s mission. The key is not to lean on one tool but to let a combination of indicators guide decisions.

• Radar and AIS: They give you real-time data on other vessels’ positions, speeds, and courses. The trick is to synthesize it with your own lookout and the weather picture, then decide on a course of action.

• VHF radio and signaling: Quick, clear communication helps prevent misunderstandings. A short transmission can clarify intentions and reduce anxiety in crowded waters.

• Visual cues and lights: Even with tech, good old-fashioned visibility matters. Proper use of navigation lights and day shapes keeps you in others’ line of sight.

• Bridge resource management: A tidy, well-communicating bridge is a big part of Rule 4’s success. Clear assignments, calm language, and a shared situational picture keep the team aligned.

If you’ve ever watched a well-run bridge team, you’ve seen Rule 4 in action. It’s quiet, disciplined, and effective, not loud or dramatic. The best crews practice this rhythm so when tension rises, the response stays clean and measured.

Common missteps and how to avoid them

No system is perfect, and the sea isn’t a classroom where perfection is guaranteed. Here are a few pitfalls that can creep into routine operations, along with simple ways to keep them in check.

• Complacency: Traffic in a familiar area feels easy, so the alertness slips. Counter it with a quick, mental traffic briefing at the start of every watch and periodic checks of radar-target lists.

• Overreliance on automation: Gadgets are great, but they don’t replace human judgment. Always cross-check electronic readings with human perception and keep the lookout engaged.

• Fatigue and miscommunication: Long watches can erode reaction time. Short, well-structured handoffs and proper rest are part of Rule 4’s safety net.

• Misreading the maneuvering room: Distance and speed aren’t constants. Reassess as weather and traffic change; what was safe one minute may not be the next.

Real-world takeaways

Rule 4 isn’t a dry citation; it’s about the responsibility you carry as a member of a crew—every person who plays a role on deck, on the bridge, or in the engine room. The rule sets the tone for how a vessel should be steered through the maze of traffic that defines modern waterways. It’s a living practice, not a fixed checklist.

If you’re wondering how to keep Rule 4 front and center, here are a few practical habits that make a difference:

• Start every watch with a quick traffic check: Look around, scan the radar, and confirm the plan with the team.

• Treat every potential collision as urgent, but not panicked: The best responses are deliberate and clear.

• Communicate early and often: State intentions, confirm others’ actions, and document outcomes as you go.

• Review and reflect after close calls: What worked, what didn’t, and what would you do differently next time?

Why this rule matters beyond the ships

The principle behind Rule 4 isn’t limited to the sea. It resonates with any situation where multiple actors share space and risk. It’s the same mindset a pilot uses when navigating crowded airways, the same discipline a driver follows in heavy traffic, the same courtesy that makes crosswalks safer for pedestrians. In every case, the core idea is simple: stay alert, respect others’ space, and act to prevent harm.

A closing thought

Rule 4 is a quiet, sturdy guardian. It asks for attention, teamwork, and disciplined action. It’s not about grand gestures; it’s about the steady, reliable practice of looking out, moving thoughtfully, and communicating with clarity. When the crew keeps that rhythm, ships glide through busy lanes with less drama and more safety.

So, next time you hear someone mention Rule 4, think not of a distant regulation, but of a daily promise: to keep the voyage safe for everyone on board, and to do your part in steering clear of harm. The ocean is grand and unpredictable, but with a vigilant crew and a steady hand on the helm, collisions become less a matter of chance and more a matter of choice. That choice—the choice to avoid collisions—rests with the crew, and that choice is exactly what Rule 4 embodies.