The short answer is that the stand-on vessel in an overtaking situation keeps course and speed, while the overtaking vessel must keep clear and pass safely. This status and duty come from navigation rules that prioritize safe passing when one vessel approaches another from behind. Understanding when you are the stand-on vessel and what obligations follow helps you act predictably, reduce collision risk, and support consistent decision-making under power or sail.
Core Rule for Overtaking
Rule 13 of the International-International Regulations for Preventing Collisions at Sea (ColRegs) governs overtaking. It states that any vessel overtaking another vessel shall keep out of the way and avoid crossing ahead or passing closely behind the stand-on vessel. The overtaking vessel must take early and substantial action to create safe distance. The stand-on vessel maintains course and speed but must also take action if the overtaking vessel fails to pass safely. Understanding this hierarchy clarifies roles before, during, and after the passing maneuver.
What Is a Stand-on Vessel?
A stand-on vessel is the vessel that has the right of way to continue its intended path when two vessels are in a close-quarters or crossing situation, as defined by the ColRegs. In an overtaking scenario, the vessel being overtaken is the stand-on vessel. That designation shifts only if the overtaking situation changes to a crossing or head-on situation, or if the overtaking vessel fails to keep clear and the situation becomes hazardous. The stand-on vessel’s advantage is the presumption that the give-way vessel will act appropriately; however, the stand-on vessel retains a duty to act if necessary to avoid collision.
When You Are the Stand-on Vessel
You are the stand-on vessel in an overtaking situation when another vessel is overtaking you from behind, typically within a sector defined by the 22.5-degree stern light and the 67.5-degree beam on either side. Specific indicators include:
- The other vessel is steadily approaching your stern quadrant on radar or visually.
- Relative bearing to the overtaking vessel remains largely unchanged over time.
- Length of overlap and closing speed suggest that the other vessel is the overtaker.
In such cases, expect the overtaking vessel to pass on your port or starboard side, and anticipate that they will keep clear. Your role is to hold your course and speed unless the situation demands intervention to avoid risk.
Immediate Responsibilities
As the stand-on vessel, your core responsibilities include monitoring the overtaking vessel, maintaining predictable motion, and preparing to act if the overtaking vessel does not give way. Specific duties include:
- Continue on your current heading and speed to preserve predictability.
- Maintain effective lookout using sight, sound, and appropriate electronics.
- Monitor the overtaking vessel’s closure rate and bearing; small changes can signal risk.
- Be ready to sound the danger signal (five or more short, rapid blasts) if the overtaking vessel appears to be on a collision course.
- If risk develops, take avoiding action as required by Rule 8, which allows the stand-on vessel to maneuver if the give-way vessel fails to act.
These steps align with a proactive, defensive approach that emphasizes early detection and clear communication of intent.
Common Misconceptions
Some mariners mistakenly believe that the stand-on vessel must never alter course or speed. In reality, the ColRegs allow the stand-on vessel to maneuver if it becomes necessary to avoid collision, especially when the give-way vessel is not taking appropriate action. Inadvertently changing course or speed without signaling can create confusion, so any deviation should be deliberate, early, and observable to others. Consistency and clear intent matter more than rigidly holding position at all costs.
Identification Checklist
Use this quick checklist to determine whether you are the stand-on vessel in an overtaking situation and what to do next:
| Factor | Indicator or Action | Notes |
|---|---|---|
| Relative Position | Overtaking from behind (stern sector) | Bearing change remains small over time |
| Lights | You see only the red and green sidelights, no stern light | Overtaking vessel shows a stern light |
| Radar | Target approaching at a steady range rate, minimal bearing change | Closure rate indicates overtaking |
| Actions | Maintain course and speed; prepare to intervene if needed | Only act if risk develops or signals are given |
| Risk Signs | Overtaking vessel closing rapidly, bearing opening changes, failure to pass | Increase vigilance and prepare maneuver |
Practical Scenarios
Powerboat Overtaking Powerboat
When one powerboat overtakes another, visualize the sector and lights to confirm overtaking status. The stand-on vessel should hold its heading and rate of turn, using small, steady inputs to maintain a steady silhouette against the background. The overtaking vessel should pass with ample distance, often leaving one boat length or more when possible. If the overtaking vessel appears off-course or too close, the stand-on vessel may briefly alter course or speed to encourage wider separation, preferably with a short sound signal such as one prolonged blast to indicate doubt.
Sailboat Overtaking Powerboat
Under sail, the overtaking rules still apply, but right of way can shift if the situation changes to a crossing or give-way hierarchy under sail rules. Typically, if the overtaking is clear, the sailboat is the stand-on vessel and should keep steady course. The power-driven overtaking vessel remains give-way. If conditions require the sailboat to tack or gybe for safety, it should do so promptly and in a predictable manner while signaling intent where sound signals are required.
Small Open Boat at Night
At night, stern navigation lights and the absence of port and starboard sidelights on your bow indicate you are being overtaken. The stand-on vessel should maintain its light configuration and avoid sudden changes. The overtaking vessel should show its passing intentions with appropriate sound signals if in doubt. Both vessels should reduce speed if visibility, traffic density, or sea conditions increase risk.
Communication and Signals
Effective communication reduces ambiguity in overtaking situations. Standard sound signals include one prolonged blast to indicate power-driven vessels about to depart a dock, two prolonged blasts to signal intent to overtake on the port side, and five or more short, rapid blasts to express doubt or danger. Lights and shapes can be used during the day when shapes are required for limited visibility or special circumstances. Clear, early signaling supports shared understanding, especially in congested waters.
Risk Management and Rules Interaction
Navigation rules interact in nuanced ways, and the stand-on vessel may become the give-way vessel if circumstances change. For example, if the overtaking situation becomes a crossing situation, Rule 15 applies, and the vessel on the starboard side becomes the stand-on vessel. Similarly, if you are overtaking in a narrow channel or traffic separation scheme, additional local rules may apply. Always assess the full traffic picture, update risk assessments, and use all available means—sight, radar, AIS, and sound—to maintain situational awareness.
Training and Drills
Regular practice reinforces the correct response to overtaking scenarios. Recommended actions include:
- Review the ColRegs for Rules 13 (Overtaking), 8 (Action to avoid collision), and 17 (Responsibilities between vessels).
- Conduct bridge or cockpit drills that simulate overtaking and failure-to-pass situations.
- Practice using radar, ARPA, and AIS to track closing vectors and bearing trends.
- Use checklists for lights, sounds, and signals to ensure consistent communication.
- Debrief real-world encounters to refine timing and distance judgments.
These habits build muscle memory and support calm, consistent execution when it matters most.
Frequently Asked Questions
- Do I have to change course if the overtaking vessel is too close? Yes, if the overtaking vessel fails to give way and a collision risk arises, you may take avoiding action under Rule 8. Act early, make your maneuver apparent, and use sound signals to clarify intent.
- What if visibility is poor and I cannot confirm overtaking status? Reduce speed, use radar and AIS to estimate vectors, sound appropriate signals, and assume overtaking intent when in doubt. Prioritize increased margin and communication.
- Can the overtaking vessel pass on either side? Normally, pass on the port side unless circumstances or local rules suggest otherwise. Ensure ample clearance and avoid forcing the maneuver in congested or restricted waters.
- Does being the stand-on vessel mean I am not responsible for collision? No. While the other vessel must keep clear, you are expected to act if the situation becomes unsafe. Vigilance and timely intervention remain your responsibility.
Conclusion
Being the stand-on vessel in an overtaking situation means holding course and speed while expecting the overtaking vessel to keep clear. Your role is stable but not passive: maintain vigilance, monitor the overtaking vessel’s behavior, and be ready to act if necessary. By applying Rule 13 consistently, signaling clearly, and practicing disciplined procedures, you support safe, predictable passing and reduce collision risk across all conditions.