🔍 Key Concepts

• Rule 9 – Narrow Channels (International & Inland) and what it says about vessels that shall not impede other vessels • The special treatment of vessels constrained by the narrow channel (those that can safely navigate only within it) • Differences between vessel not under command (NUC), vessel engaged in surveying, and small vessels under 20 meters

💭 Think About

• Which type of vessel does Rule 9 specifically mention as having a duty not to impede a vessel that can safely navigate only within a narrow channel or fairway? • Does a vessel not under command have the ability to maneuver to avoid impeding another vessel, or is it defined by its inability to maneuver? • Between a small power-driven vessel under 20 m, a survey vessel, and a NUC vessel, which ones are expected to keep out of the way of a large ship that is confined to the channel?

✅ Before You Answer

• Look up the exact wording of Rule 9(b) and 9(c) in the Navigation Rules about vessels less than 20 meters and sailing vessels in narrow channels • Confirm the definition and responsibilities of a vessel not under command (Rule 3(f)) – can it be required not to impede others? • Verify whether surveying is specifically named in Rule 9 as a category that must not impede a vessel that can safely navigate only in the narrow channel