Traffic off the port bow
A different crossing role. Developing level, about 3 min. International COLREGs / IRPCS. COLREGs Rules 15–17.
The situation
You are under power in open water. Another power-driven vessel approaches from your port side with a steady bearing and closing range. Both vessels are in sight. Observe whether she takes action.
What is your initial role in this crossing?
- Maintain course and speed while monitoring her: Remain predictable and continue the lookout.
- Turn to port towards the contact: Try to pass behind her.
- Alter immediately without observing her action: Change the crossing geometry now.
Answers and explanations
Lookout: Identify the side of the approaching contact from your own vessel, then monitor her action.
The sound answer
Maintain course and speed while monitoring her
Initially you are the stand-on vessel. In this authored replay Kestrel makes a substantial alteration and passes clear. If she failed to act, the later provisions of Rule 17 would require reassessment.
Why the other options fall short
Turn to port towards the contact
At this early stage you should remain predictable. A turn towards a vessel on your port side can also conflict with her expected starboard alteration.
Alter immediately without observing her action
An initial stand-on role means maintaining course and speed while keeping watch. Reassess when the circumstances justify or require action; this replay contains a complying give-way vessel.
Rules 15–17 · Crossing roles and continued lookout
The vessel with the other on her starboard side keeps out of the way. The stand-on vessel initially keeps course and speed, while retaining the later responsibilities described in Rule 17.