Coming up from astern
Overtaking. Developing level, about 3 min. COLREGs Rule 13.
The situation
You are gaining on a slower vessel from directly astern. You have open water to starboard and no other traffic in the exercise.
What is your responsibility?
- Keep clear to starboard: Create lateral separation while overtaking.
- Continue close behind: Expect the slower vessel to move aside.
- Reduce speed and stay astern: Avoid the overtake and maintain separation.
Lookout: Your approach is from more than 22.5° abaft the other vessel’s beam. If in doubt, assume you are overtaking.
Sound answers
Keep clear to starboard
As the overtaking vessel, you must keep out of the way until finally past and clear. Rule 13 does not prescribe a passing side for this open-water exercise; starboard is the authored clear-water route.
Reduce speed and stay astern
Reducing speed and remaining safely astern is another way to keep out of the way in this exercise. An overtake is optional; your responsibility to keep clear is not.
Why the other options fall short
Continue close behind
The vessel being overtaken does not become the give-way vessel just because you are faster. Your responsibility to keep clear continues until finally past and clear.
Rule 13 · Overtaking
A vessel overtaking another keeps out of the way of the vessel being overtaken. That duty continues until she is finally past and clear, even if the bearing changes during the manoeuvre.