🔍 Key Concepts

• Rule 9 – Narrow Channels: Vessels that can safely navigate only inside the channel have special priority. • The obligation of a vessel crossing a narrow channel and the phrase "shall not impede" in Rule 9. • Difference between a normal crossing situation (Rule 15) and a situation that occurs inside or across a narrow channel.

💭 Think About

• Ask yourself: Does the fact that vessel A can only navigate within the channel change the usual port/starboard crossing rule? • If you, on vessel B, continue across, will you impede vessel A’s safe passage along the channel? What does Rule 9 say you must do in that case? • Under what circumstances would you sound the danger signal, and do you already have a clear Rule telling you who must keep out of the way here?

✅ Before You Answer

• Verify the exact wording in Rule 9(b)/(d) – Narrow Channels about vessels crossing or not impeding a vessel that can safely navigate only within a narrow channel. • Confirm that vessel B is crossing the channel and vessel A is constrained to the channel by her draft or available depth/width. • Before choosing, be sure you are applying Rule 9 first, and only then considering the normal crossing rule (Rule 15), rather than the other way around.