Rule 17 clarified: when does a stand-on vessel keep its course?

Outline (skeleton)

• Hook: Why Rule 17 matters on the water and how a simple idea keeps ships safe.

• What Rule 17 really says: stand-on vs give-way, and the core idea—keep your course when it’s safe.

• The big principle in plain terms: safety first, avoid confusion, act only when needed.

• Common situations and how they play out in real life (crossing, overtaking, changing conditions).

• Why following this rule matters beyond a quiz question—risk, responsibility, and keeping calm on the bridge.

• Practical tips to keep the line steady: situational awareness, communication, and using instruments.

• Quick recap and a few reflective thoughts.

Secrets of Rule 17: when to hold your course and why it matters

Let me explain something that often feels like a small zinger in a big sea of rules: Rule 17 of the COLREGs—often summarized as the stand-on rule—tells a stand-on vessel to maintain its course when it’s safe to do so. In other words, if you have the right of way, you don’t start zigzagging or weaving just because the other vessel is nearby. You stay steady, keep your speed, and watch the other boat to make sure the path remains clear. That’s the essence. The give-way vessel, on the other hand, is the one that’s supposed to adjust—alter course or speed—to avoid a collision.

That sounds almost too simple, right? But here’s the subtle beauty: this rule is about clarity and predictability. When the stand-on vessel keeps a straight line and the give-way vessel acts decisively to avoid, there’s less confusion on the water. People and machines can anticipate what comes next, which is exactly what you want when you’re dealing with moving ships, weather, and the occasional gust that shakes the deck.

What “safe to do so” actually means

The heart of the rule is safety. “Safe to do so” isn’t a vague phrase; it’s a real threshold. If continuing on your present course would bring you or the other vessel into danger, it’s time for a change. The stand-on vessel may still be expected to take action if it becomes apparent that collision cannot be avoided by the other vessel’s actions alone. But if the course you’re holding puts you and the other vessel on a collision path, then the situation has shifted, and the stand-on vessel cannot be a passive bystander.

Think of it this way: you’re steering a steady, clear line through a traffic pattern at sea. If that line safely takes you past the other ship with room to spare, you stay the course. If not, you adjust. The contrast is what keeps the scene orderly—no frantic steering, no sudden swerve that creates new hazards for others.

Where you’ll most often feel Rule 17 in action

• Crossing situations: This is the classic scenario people picture when they imagine stand-on vs give-way. If you’re the stand-on vessel in a crossing situation, you hold your course unless it becomes unsafe. The other vessel—the give-way vessel—should take early and decisive action to avoid you. The goal is to pass well clear and avoid a collision with predictable, orderly movements.

• Overtaking: In overtaking, the dynamics shift a bit. The overtaking vessel is normally the one to pass on the appropriate side, while the vessel being overtaken keeps its course if safe. The principle remains consistent: don’t change course just to confuse the other guy; act only when it makes things safer.

• Open seas and busy lanes: In open waters with plenty of room, holding course is often straightforward. In busier lanes, you’ll see Rule 17 tested more—visibility, traffic density, and weather all push the “is it safe to hold?” question to the front.

Why this isn’t just a test-answer kind of idea

This rule isn’t about proving you know a line in a book; it’s about real-world thinking under pressure. If you’re the stand-on vessel and you’re holding your course, you’re signaling that you’re confident in your path and within your right of way. If the give-way vessel sees danger, it should act early and clearly. The aim isn’t to trap the other guy or to prove you’re “the boss” on the water; it’s about staying predictable so everyone can maneuver safely.

You might think, “What if the other vessel isn’t behaving?” That’s where a calm, methodical approach helps. If it becomes apparent that collision can’t be avoided by the give-way vessel’s actions alone, then the stand-on vessel may need to take action to avert disaster. It’s not about stubbornly sticking to a line; it’s about preserving safety and clarity until a safer path emerges.

Real-life tangents that still connect back

If you’ve ever watched ships slip by a harbor or seen a tug convoy threading a channel, you’ve witnessed Rule 17 in action without labeling it. The captains aren’t playing a game; they’re reading the other vessel’s movement, keeping a steady.

And here’s a practical aside that often helps beginners: radios and AIS make the exchange easier, but they don’t replace good seamanship. You still need to monitor radar, keep your speed in check, and be ready to adjust if the situation shifts. The tools help you see what’s coming; your judgment keeps you from overreacting or underreacting.

Short, clear guidelines you can carry aboard

• Maintain situational awareness. Keep looking around, use all available information, and monitor the other vessel’s actions.

• Hold your course when safe. If you’re the stand-on vessel, don’t drift away from your intended path unless you’ve clearly run into risk.

• Expect action from the give-way vessel. If you’re in the other boat, plan early and execute decisively to avoid a collision.

• Communicate when needed. If things get tight, clear signaling and, if necessary, a deliberate maneuver can prevent a close call.

• Reassess as conditions change. Weather, visibility, or the other vessel’s behavior can turn a safe situation into a tighter one in a heartbeat.

A few practical tips for navigating the rules with confidence

• Think like a watcher on a busy street. You’re not the only vessel; you’re part of a moving system. Predict what others might do and match your actions to that expectation.

• Keep the line clean and straightforward. Don’t overreact to every minor wobble or small change in speed. The idea is to stay predictable, not to chase every ping of your compass.

• Use the instruments, but don’t let instruments own your decisions. Visual cues and sound signals still matter as much as electronics.

• Practice good bridge habits. Clear communication, short phrases, and calm voices help prevent misinterpretations in tense moments.

• Respect the human element. Weather, fatigue, or miscommunication can affect decisions. Give yourself room to make prudent choices.

A closing reflection

Rule 17 isn’t about memorizing a rigid script; it’s about cultivating a mindset of safety and clarity on the water. The stand-on vessel keeps its course when it’s safe to do so, and the give-way vessel makes the necessary moves to avoid a collision. When both parties play their parts well, a busy sea lane feels less like a chessboard and more like a well-choreographed dance—one where every move is predictable, smooth, and focused on getting everyone home safely.

If you’re curious to see Rule 17 in action, watch ships maneuvering near a busy harbor or a coastal passage. Listen for the cadence of radio calls, watch how each captain tracks the other vessel’s path, and notice how the crew communicates intent. There’s a lot you can learn from observing real-world practice—beyond any single quiz question, it’s about developing a practiced sense of judgment, patience, and seamanship.

Final takeaway: the correct takeaway from Rule 17 is simple in principle and powerful in practice. A stand-on vessel maintains its course when it’s safe to do so, allowing the give-way vessel to take action to avoid a collision. But the moment safety bleeds, the line changes. And that is exactly how mariners keep the sea a safer place for everyone who sails it.