1.10 Responsibilities Between Vessels — the Pecking Order (Rule 18)

Rule 18: The "Pecking Order" of Vessels

Rules 14, 15, and 17 tell you how two power-driven vessels sort out a head-on or crossing situation. But the water is full of vessels that are not ordinary power-driven vessels — tugs restricted in their ability to maneuver, trawlers with gear in the water, sailboats, disabled ships. Rule 18 is the master hierarchy that decides who keeps clear of whom when different types of vessel meet. Because Rules of the Road is graded at 90%, memorizing this order cold is one of the highest-yield things you can do for the exam.

The order of privilege

Read the list from the top down. Each vessel type must keep out of the way of every type above it:

A common mnemonic is "New Reels Catch Fish So Poorly." The vessel lower on the list is always the give-way vessel; the one higher up is stand-on.

Putting it in the words of the rule itself:

• A power-driven vessel underway keeps out of the way of NUC, RAM, fishing, and sailing vessels.
• A sailing vessel underway keeps out of the way of NUC, RAM, and fishing vessels.
• A vessel engaged in fishing underway keeps out of the way, so far as possible, of NUC and RAM vessels.

"Fishing" has a narrow legal meaning

On the exam, "engaged in fishing" means fishing with nets, lines, trawls, or other apparatus that restricts maneuverability — a working commercial trawler or longliner. It does not include a sport-fishing boat trolling with rod and reel, and it does not include a vessel with trolling lines that do not restrict maneuverability. Your six-pack charter running trolling lines is still a plain power-driven vessel and enjoys none of Rule 18's fishing privileges.

The special case of "constrained by draught"

A vessel constrained by her draught (a deep-draft ship that can only stay inside a dredged channel) is not owed a full "keep out of the way." Instead, Rule 18(d) says other vessels shall, if circumstances admit, avoid impeding her safe passage. "Avoid impeding" is a lower duty than "keep out of the way": it means do not put yourself in a position that forces her to maneuver. Note that CBD exists only under the International Rules — there is no constrained-by-draught status on U.S. Inland waters, a favorite exam trap.

Seaplanes and WIG craft

A seaplane on the water shall, in general, keep well clear of all vessels and avoid impeding their navigation, but where risk of collision exists it follows the steering and sailing rules like any other vessel. A WIG (wing-in-ground) craft on take-off, landing, or in flight near the surface keeps well clear of all other vessels; when operating on the surface it behaves as a power-driven vessel.

The traps that catch candidates

Trap 1 — Rule 18 does not override overtaking. The rule opens with "Except where Rules 9, 10, and 13 otherwise require…" Rule 13 (overtaking) always wins. If a sailing vessel overtakes a power-driven vessel, the sailing vessel is the give-way vessel — even though "power gives way to sail" normally. Once overtaking, always overtaking, regardless of type.

Trap 2 — geometry does not matter across types. Imagine your power charter is crossing and a working trawler is off your port bow. In a plain power-vs-power crossing you would be the stand-on vessel (the other is on your port side). But because the other vessel is fishing, Rule 18 makes you keep out of the way regardless of which side she is on. Type beats geometry.

Trap 3 — privilege is not immunity. A NUC or RAM vessel sits at the top of the order, but she is not entitled to stand on into a collision. If risk of collision develops and the give-way vessel is not acting, every vessel must take action to avoid collision (Rule 2, "the ordinary practice of seamen," and Rule 17's in-extremis provision).

Trap 4 — same-type meetings. Rule 18 only resolves meetings between different types. Two power-driven vessels use Rules 14/15; two sailing vessels use Rule 12 (the windward/leeward and port/starboard-tack rules). Rule 18 is silent when both vessels are the same type.

Worked example

You are running a power-driven six-pack. Dead ahead and slightly to port, a commercial vessel shows the day shape and gear of a trawler crossing your track. You would like to hold your course. Rule 18 says a power-driven vessel keeps out of the way of a fishing vessel, so you are give-way: take early, substantial action (Rule 8) — a bold course change to pass well astern of her, or slow and let her cross. Do not stand on merely because she is on your port bow.