Rule 18
Responsibilities between vessels
The pecking order: power gives way to sail, sail to fishing, fishing to RAM and NUC — except where Rules 9, 10, and 13 say otherwise.
- 1NUCNot under command
exceptional circumstance — cannot maneuver; everything keeps clear of her
- 2RAMRestricted in ability to maneuver
the nature of her work restricts her (dredging, cable-laying, towing that restricts…)
- 3CBDConstrained by draftInternational only
deep draft in shallow, narrow water — avoid impeding her
- 4FISHEngaged in fishing
nets, trawls, or lines that restrict maneuverability — not trolling
- 5SAILSailing vessel
under sail alone — engine on means power-driven
- 6POWERPower-driven vessel
gives way to every vessel above
In plain language
When vessels of different types meet, the more maneuverable gives way to the less maneuverable. From most privileged down: not under command, restricted in ability to maneuver, constrained by draft (International only), fishing, sailing, power-driven — remember “New Reels Catch Fish So Purchase some”. Each vessel keeps out of the way of every type above it on the ladder. But three rules outrank this hierarchy: narrow channels (9), traffic schemes (10), and overtaking (13) — an overtaking sailboat still gives way to the ship she is passing.
This rule differs under the US Inland Rules. Change the rule set in language and regional settings to see the difference.
Easily confused with
- Rule 13 — Overtaking
The hierarchy yields to Rules 9, 10, and 13 — an overtaking vessel keeps clear no matter what type she is.