Haven approach · B · night · channel traffic
Voyage 5 of 5 · act and replay. Advanced level, about 3 min. International COLREGs / IRPCS. COLREGs Rule 9(b), (d).
The situation
Your approach now requires a crossing of the channel. A 100 m ship heading south can navigate safely only within it. You are in a 12 m boat outside the eastern edge, intending to cross west. She is on your starboard side and closing.
How do you avoid impeding her passage?
- Stop outside the channel; cross astern when she is clear: The example waits before resuming the crossing.
- Keep speed and cross ahead: Expect the ship to manoeuvre around you.
- Increase speed to cut across the bow: Try to get across first.
Answers and explanations
Lookout: The narrow-channel constraint matters alongside the encounter. Waiting outside the channel can preserve room for the ship.
The sound answer
Stop outside the channel; cross astern when she is clear
Rule 9(b) and (d) require you not to impede the channel-bound ship. This authored stop leaves you outside the channel; the example later crosses astern. Its waiting time illustrates this geometry and is not a legal timer.
Why the other options fall short
Keep speed and cross ahead
You must not cross so as to impede a ship that can safely navigate only within the channel.
Increase speed to cut across the bow
A speculative dash ahead leaves little margin and does not fulfil the duty not to impede her passage.
Rule 9(b), (d) · Narrow channel crossing
Vessels under 20 m shall not impede a vessel that can safely navigate only within a narrow channel. A vessel shall not cross a channel if doing so impedes that vessel.