Rule 18 — Who Keeps Out of the Way of Whom

What the rule requires

On this exam you are nearly always the power-driven vessel, so learn your own paragraph first. A power-driven vessel underway shall keep out of the way of a vessel not under command, a vessel restricted in her ability to maneuver, a vessel engaged in fishing, and a sailing vessel 33 CFR §83.18. The International text reads word for word the same COLREGs Rule 18, so any question resting on paragraph (a) alone is a "(Both International & Inland)" question with no divergence trap in it.

Under sail, the list shortens. A sailing vessel underway keeps out of the way of a vessel not under command, a vessel restricted in her ability to maneuver, and a vessel engaged in fishing. A power-driven vessel does not appear on that list, and nothing in Rule 18 puts a duty on a sailing vessel toward one.

A vessel engaged in fishing when underway shall, so far as possible, keep out of the way of a vessel not under command and a vessel restricted in her ability to maneuver. Two classes only, and the duty carries a qualifier the other two paragraphs do not have. Examiners write answer options around that qualifier.

The ladder, and what it leaves out

The device in general circulation is New Reels Catch Fish So Purchase Some: Not under command, Restricted in ability to maneuver, Constrained by draft, Fishing, Sail, Power. Use it for the order and nothing else, because three things it cannot tell you are exactly what the harder questions turn on.

The C rung has no Inland counterpart.
The constrained-by-draft vessel is owed a weaker duty than the classes above her, and two classes owe it not at all.
Each paragraph of the rule is a closed list. A vessel owes the classes named in her own paragraph and no others, which is why a vessel engaged in fishing owes nothing to a sailing vessel even though sail sits below fishing on the ladder.

Add one more restriction. Paragraphs (a), (b) and (c) each address a vessel underway; Rule 18 assigns no duty to a vessel that is not.

The eight words at the top

The rule opens "Except where Rules 9, 10, and 13 (§§ 83.09, 83.10, and 83.13) otherwise require," and the International text carries the same reservation. When the facts of a question put you inside one of those three rules, the ranking is not your authority and the ladder answer is the distractor that was planted for you. Those rules have their own lessons; what you carry out of Rule 18 is the habit of checking for them before you rank anybody.

A vessel engaged in fishing and a sailing vessel are approaching each other in open water, with no Rule 9, 10 or 13 situation in play. Which one keeps out of the way?

The sailing vessel. Paragraph (b) of the rule places a vessel engaged in fishing on the sailing vessel's list of classes to keep clear of. Working it from the other side confirms it: the fishing vessel's own list holds only a vessel not under command and a vessel restricted in her ability to maneuver, and a sailing vessel is neither. Same answer under both regimes.

Constrained by draft: International only

Any vessel other than a vessel not under command or a vessel restricted in her ability to maneuver shall, if the circumstances of the case admit, avoid impeding the safe passage of a vessel constrained by her draft exhibiting the signals in Rule 28, and that vessel shall navigate with particular caution having full regard to her special condition .

Paragraph (d) of the Inland rule is [Reserved] . An "(Inland Only)" question offering a constrained-by-draft answer is offering an empty class. An "(International Only)" question usually hinges on one of the two conditions written into the paragraph: she must be exhibiting the Rule 28 signals, and the duty binds only if the circumstances of the case admit.

Seaplanes and WIG craft

Both regimes word these identically, and they are worth about one question. A seaplane on the water shall in general keep well clear of all vessels and avoid impeding their navigation; where risk of collision exists she complies with Rules 4 through 19 (§§ 83.04 through 83.19). A WIG craft, when taking off, landing and in flight near the surface, keeps well clear of all other vessels and avoids impeding their navigation; when she is operating on the water surface she complies with those same rules as a power-driven vessel.

A WIG craft is operating on the water surface and a sailing vessel is crossing ahead of her. Who keeps out of the way?

The WIG craft. On the surface she is handled as a power-driven vessel, which puts her under paragraph (a) with its duty toward a sailing vessel. Her "keep well clear of all other vessels" status belongs to taking off, landing and flight near the surface, and a question that describes her on the water has taken that status away from her.

Telling it apart

Four different verbs appear in this one rule, and the criterion that separates them is how hard the duty binds. Candidates who learn only the ladder learn one verb and apply it to all four.

Keep out of the way — unqualified, and it is what paragraphs (a) and (b) impose. If the class is named on your paragraph's list, you keep out of the way of her, full stop.
So far as possible, keep out of the way — the fishing vessel's duty toward a vessel not under command and a vessel restricted in her ability to maneuver. Most often misfiled by dropping the qualifier and picking the flat "shall keep out of the way" option.
Avoid impeding the safe passage, if the circumstances of the case admit — the duty owed to a vessel constrained by her draft under International. Weaker than keeping out of the way, conditional on her exhibiting the Rule 28 signals, and owed by every class except a vessel not under command and a vessel restricted in her ability to maneuver, which the paragraph excuses by name.
Keep well clear and avoid impeding their navigation — the seaplane on the water and the WIG craft in flight near the surface. It reverts to full compliance with Rules 4 through 19 once risk of collision exists, so it is not a standing exemption from the steering rules.

Working a question

You have the 78-foot power-driven passenger vessel underway offshore, International waters. A vessel engaged in fishing is on your starboard bow. A sailing vessel is on your port bow. Ahead of you is a vessel constrained by her draft, exhibiting the signals in Rule 28.

Fix your own status before anyone else's. Power-driven, underway, which makes you the addressee of paragraph (a).
Test the exception clause. Nothing in the facts places this meeting inside Rules 9, 10 or 13, so the responsibilities in Rule 18 govern and the ranking is live.
Take the other vessels against your own paragraph one at a time. A vessel engaged in fishing is on the list. A sailing vessel is on the list. You keep out of the way of both, and neither duty is qualified.
Check what they owe you, because an option will be written to suggest one of them gives way. The sailing vessel's paragraph names three classes and a power-driven vessel is not among them; the fishing vessel's paragraph names two and you are neither. Under this rule, nothing.
Handle the constrained-by-draft vessel separately, and with the weaker verb. You are neither not under command nor restricted in your ability to maneuver, so the duty falls on you: avoid impeding her safe passage if the circumstances of the case admit. She is exhibiting the Rule 28 signals, so the condition is met.
Decide the label before you commit. Steps 1 through 4 read identically in the Inland rule. Step 5 has no Inland counterpart, paragraph (d) there being reserved, so any answer built on the constrained-by-draft vessel belongs only to an International question.

Where candidates lose the point

Choosing "the power-driven vessel keeps out of the way" on facts that were never a Rule 18 problem. The ladder is the first thing learned and the last thing questioned, so it gets applied to a scenario the rule expressly hands off to Rules 9, 10 or 13. Read the opening words of the rule as part of the rule, not as a preamble to skip.

Answering that a vessel engaged in fishing must keep out of the way of a sailing vessel. This comes from treating the ladder as a full round-robin in which every rung owes every rung above it. Paragraph (c) names two classes, and neither of them is a sailing vessel.

Reversing fishing and sail. "Sail over power" is drilled so hard that some candidates promote sail over everything short of a vessel not under command. Sail is below fishing: the sailing vessel keeps out of the way of a vessel engaged in fishing, and the reverse is nowhere in the rule.

Picking a constrained-by-draft answer on an "(Inland Only)" question. The class is genuinely absent Inland, paragraph (d) being reserved. Read the label first on any question that mentions draft.

Upgrading the constrained-by-draft duty to "keep out of the way." The paragraph says avoid impeding her safe passage, if the circumstances of the case admit, and it applies to a vessel exhibiting the Rule 28 signals. Two classes are exempt from it altogether, which is the part most often missed when the option reads "all vessels shall keep clear."

Taking "keep well clear of all vessels" as putting the seaplane at the top of the ladder, or as putting her outside the steering rules. Neither. She keeps well clear as a general matter, and where risk of collision exists she comes under Rules 4 through 19 like anyone else.

Check yourself

(Both International & Inland) You are underway on a power-driven vessel. A vessel restricted in her ability to maneuver is off your port bow and a vessel engaged in fishing is off your starboard bow. What are your obligations?

Keep out of the way of both. Paragraph (a) lists a vessel restricted in her ability to maneuver and a vessel engaged in fishing among the classes a power-driven vessel underway keeps clear of, and the duty is unqualified in each case. The wording is the same in the Inland and International rules, so the regime does not change the answer.

(Both International & Inland) A vessel engaged in fishing is underway and meets a vessel restricted in her ability to maneuver. What does the rule require of the fishing vessel?

So far as possible, she keeps out of the way of the vessel restricted in her ability to maneuver. An option reading "shall keep out of the way" without the qualifier is wrong on the face of the text, and an option putting the duty on the restricted vessel reverses the rungs.

(Both International & Inland) You are under sail and a power-driven vessel of 200 feet is crossing from your starboard side. Does Rule 18 require you to keep clear of her?

No. The sailing vessel's paragraph names a vessel not under command, a vessel restricted in her ability to maneuver, and a vessel engaged in fishing. A power-driven vessel is not on that list, and her length does not add her to it. Whether some other rule bears on the meeting is a separate matter; the rule opens by subordinating itself to Rules 9, 10 and 13, so check whether the facts have put you in one of those before you answer from the ranking.

(International Only) A vessel constrained by her draft is exhibiting the signals in Rule 28 and a vessel restricted in her ability to maneuver is working nearby. Which of them must avoid impeding the other?

Neither is required to avoid impeding by this paragraph. The duty to avoid impeding the safe passage of a vessel constrained by her draft falls on any vessel other than a vessel not under command or a vessel restricted in her ability to maneuver. The constrained vessel's own obligation is to navigate with particular caution having full regard to her special condition.

(Inland Only) Your power-driven vessel is meeting a deep-draft ship that can only stay in the deepest water available. Which answer does the Inland rule support?

None that rests on a constrained-by-draft status, because Inland has no such class. Paragraph (d) of the Inland responsibilities rule is reserved. Any answer option using the phrase "constrained by her draft" on an Inland-labelled question is a distractor.

(Both International & Inland) A seaplane is on the water and risk of collision exists between her and your vessel. What governs the meeting?

Rules 4 through 19. The seaplane's general obligation to keep well clear of all vessels and avoid impeding their navigation gives way, once risk of collision exists, to compliance with those rules the same as any other vessel. An option stating that all vessels must keep clear of a seaplane on the water misreads a general instruction as a right of way.