Rule 9 — Narrow Channels: Keeping to the Starboard Side, and Who Gives Way in It

What the rule requires

Keep as near to your starboard-side limit as is safe and practicable

A vessel proceeding along the course of a narrow channel or fairway keeps as near to the outer limit of the channel or fairway which lies on her starboard side as is safe and practicable 33 CFR §83.09. The International text is word-for-word the same, so this is a "Both International & Inland" fact COLREGs Rule 9(a).

Two things in that sentence decide questions. The trigger is proceeding along the course of the channel — a vessel crossing it is governed by paragraph (d) instead, not by the keep-right requirement. And the standard is safe and practicable, not absolute: the rule does not order a vessel into water she cannot use.

The Inland downbound rule — the single highest-yield item on this topic

Notwithstanding the keep-right requirement and Rule 14(a), a power-driven vessel operating in a narrow channel or fairway on the Great Lakes, Western Rivers, or waters specified by the Secretary, proceeding downbound with a following current, has the right-of-way over an upbound vessel, shall propose the manner and place of passage, and shall initiate the maneuvering signals prescribed by Rule 34(a)(i). The upbound vessel shall hold as necessary to permit safe passing .

That paragraph carries three separate privileges for the downbound vessel, and the exam exploits it: the stem gives you the situation, three of the four options each state one privilege, and the answer is "All of the above." Learn them as a set of three rather than as a single "downbound has right-of-way."

Four conditions must all hold before the paragraph switches on: Inland rules apply, the water is one of the three named categories, the vessel is power-driven, and she is downbound with a following current. Fail any one and you are back on ordinary Rule 9(a)(i) and the meeting rules.

The word notwithstanding is doing real work. This paragraph displaces both the keep-to-starboard requirement and Rule 14(a), which is why the downbound vessel is the one who names the manner and place of passage.

You are upbound in a narrow reach of the Western Rivers, making good four knots against the current. A downbound towing vessel comes into view. Who proposes the passing arrangement, and what is your obligation?

The downbound vessel proposes the manner and place of passage and initiates the maneuvering signals under Rule 34(a)(i); she holds the right-of-way. Your obligation is to hold as necessary to permit safe passing . You do not propose, and you do not signal first.

Overtaking in the channel — the regimes diverge

Under Inland, in a narrow channel or fairway when overtaking, the power-driven vessel intending to overtake another power-driven vessel indicates her intention by sounding the appropriate signal prescribed in Rule 34(c) and takes steps to permit safe passing. The vessel being overtaken, if in agreement, sounds the same signal and may, if specifically agreed to, take steps to permit safe passing. If in doubt she shall sound the signal prescribed in Rule 34(d) .

Under International, the paragraph engages only where overtaking can take place only if the vessel to be overtaken has to take action to permit safe passing. The overtaking vessel sounds the signal in Rule 34(c)(i); the vessel to be overtaken, if in agreement, sounds the signal in Rule 34(c)(ii) — a different signal, not the same one — and takes steps to permit safe passing. If in doubt she may sound the signals in Rule 34(d) COLREGs Rule 9(e).

So there are four separable differences: the trigger condition, who is covered (Inland names power-driven vessels on both ends), whether the agreement signal is identical or a second distinct signal, and whether the doubt signal is mandatory or permissive.

Both regimes close the paragraph the same way: this Rule does not relieve the overtaking vessel of her obligation under Rule 13.

Rule 9 tells you when to sound and who sounds first. What the signal consists of is Rule 34's business, and Rule 9 does not restate it.

A vessel nearing a bend, or an area of a narrow channel or fairway where other vessels may be obscured by an intervening obstruction, navigates with particular alertness and caution and sounds the appropriate signal prescribed in Rule 34(e) . Identical under International COLREGs Rule 9(f).

The trigger is that vessels may be obscured. Nothing has to be sighted, heard, or known to be there. A blind bend with no traffic in it still requires the signal.

Anchoring

Any vessel shall, if the circumstances of the case admit, avoid anchoring in a narrow channel — same text in both regimes COLREGs Rule 9(g), .

Telling it apart: the three "shall not impede" paragraphs

Candidates lump (b), (c) and (d) together as "small boats stay out of the way." They are three different duties, and the criterion that separates them is whose passage you may not impede.

Rule 9(b) — a vessel of less than 20 meters in length, or a sailing vessel of any length. She shall not impede the passage of a vessel that can safely navigate only within a narrow channel or fairway 33 CFR §83.09. The duty is conditional on the other vessel being confined to the channel. Most often misfiled: a large vessel that has water outside the channel and is not confined to it — 9(b) does not reach that case, and length alone does not create the duty.
Rule 9(c) — a vessel engaged in fishing. She shall not impede the passage of any other vessel navigating within a narrow channel or fairway. No confinement test, no length test, and no size limit on the fishing vessel. This is the broadest of the three COLREGs Rule 9(c).
Rule 9(d) — any vessel crossing. She must not cross if the crossing impedes the passage of a vessel which can safely navigate only within the channel. Inland: the confined vessel must use the signal prescribed in Rule 34(d) if in doubt as to the crossing vessel's intention . International: she may use it COLREGs Rule 9(d). Same substance, different obligation on the whistle.

The 20-meter threshold in (b) is arbitrary and simply has to be carried in. There is nothing to derive it from.

Each of these paragraphs places a duty on the named vessel. None of them states that the other vessel has the right-of-way, and none of them says the vessel under 20 meters must stay out of the channel altogether. The requirement is not to impede passage.

You are engaged in fishing, 30 meters in length, in a dredged channel. A 60-meter coastal freighter is inbound; there is deep water on both sides of the channel and she is not confined to it. Are you under a duty toward her?

Yes. Rule 9(c) applies to a vessel engaged in fishing and requires that she not impede any other vessel navigating within the channel or fairway, with no test of whether that vessel is confined to it . Your length is irrelevant here; the 20-meter figure belongs to paragraph (b).

Working a question

Inland rules apply. You are upbound in a narrow channel on the Western Rivers, making good five knots against the current, approaching a right-hand bend with a high bank that blocks the view. A downbound towing vessel with the current behind her is somewhere above the bend.

Fix the regime. Western Rivers puts you in the Inland Rules, so 33 CFR §83.09(a)(ii) is live. Under International there is no downbound-privilege paragraph at all.
Test the four conditions. Narrow channel on Western Rivers, power-driven vessel, proceeding downbound, with a following current. All four hold for the tow, so she has the right-of-way over you 33 CFR §83.09.
Sound for the bend before anything else. You are nearing an area where another vessel may be obscured by an intervening obstruction, so you navigate with particular alertness and caution and sound the signal prescribed in Rule 34(e). That duty stands on its own and does not depend on who has the right-of-way.
Wait for her proposal. The downbound vessel proposes the manner and place of passage and initiates the maneuvering signals under Rule 34(a)(i). You do not open the exchange.
Hold as necessary. Your obligation is to hold as necessary to permit safe passing. On a licence question, "hold" is the operative word — not "alter to starboard and pass port to port," which is what Rule 14(a) would have produced and which paragraph (a)(ii) displaces.
Keep your side of the channel except as the agreed passage requires. Absent an agreement to the contrary you are still on the starboard-side outer limit as is safe and practicable, since (a)(ii) yields only what it says it yields.

Change one fact — no following current behind her — and step 2 fails. The downbound privileges never arise, and the meeting is worked under the ordinary rules.

Where candidates lose the point

Reversing the downbound rule. A candidate who half-remembers "the vessel stemming the current has better control, so she has the right-of-way" will pick the upbound vessel. The text is explicit: the downbound vessel with the following current has the right-of-way, and the upbound vessel holds 33 CFR §83.09.

Applying the downbound rule on the wrong water or under the wrong regime. It is tempting on any river with a current. The named waters are the Great Lakes, Western Rivers, or waters specified by the Secretary, and the paragraph exists only in the Inland text — a question labelled "(International Only)" about a downbound vessel is testing whether you know that.

Picking one downbound privilege when the question offers all three. Right-of-way, proposing the manner and place of passage, and initiating the maneuvering signals are three separate obligations in one paragraph. Options that state each one individually are all true, and the answer is the one that includes them.

Reading 9(b) as "vessels under 20 meters must keep clear of large vessels." The duty runs only toward a vessel that can safely navigate only within the channel or fairway COLREGs Rule 9(b). Where the other vessel is not so confined, the paragraph does not apply, however large she is.

Treating an agreed overtaking as a transfer of responsibility. After the whistle exchange, candidates answer that the overtaken vessel is now responsible for keeping clear. Rule 9(e)(ii) says the Rule does not relieve the overtaking vessel of her obligation under Rule 13 .

Missing "may" against "shall" on the doubt signal. Inland makes the Rule 34(d) signal mandatory for the vessel in doubt in both the crossing case and the overtaking case; International makes it permissive. Two identical-looking answer options separated only by "must" and "may" are testing exactly this.

Check yourself

(Inland Only) You are downbound with a following current in a narrow channel on the Great Lakes and meet an upbound power-driven vessel. Which statements are true?

You have the right-of-way, you must propose the manner and place of passage, and you must initiate the maneuvering signals prescribed by Rule 34(a)(i). All three are true together, and the upbound vessel holds as necessary to permit safe passing 33 CFR §83.09.

(International Only) You are overtaking a power-driven vessel in a narrow channel. There is ample room and she need take no action for you to pass safely. Must you sound the signal in Rule 34(c)(i)?

No. International Rule 9(e)(i) engages only where overtaking can take place only if the vessel to be overtaken has to take action to permit safe passing COLREGs Rule 9(e). Under Inland the signal requirement attaches to overtaking in a narrow channel without that qualifier .

(Inland Only) You have signalled your intention to overtake another power-driven vessel in a narrow channel. She agrees. What does she sound?

The same signal you sounded. Inland requires the vessel being overtaken, if in agreement, to sound the same signal, and she may take steps to permit safe passing if that was specifically agreed to . Under International she answers with the different signal prescribed in Rule 34(c)(ii) and takes steps to permit safe passing .

(Both International & Inland) You are approaching a bend in a narrow channel where the bank obscures the water beyond. You have seen no traffic all morning and hear nothing. What is required?

Navigate with particular alertness and caution and sound the appropriate signal prescribed in Rule 34(e) . The trigger is that other vessels may be obscured by the intervening obstruction, not that any have been detected COLREGs Rule 9(f).

(Both International & Inland) You are under sail, 12 meters in length, and wish to cross a narrow channel occupied by a deep-draft vessel that cannot leave it. What does Rule 9 require of you?

Two paragraphs bear on it. As a sailing vessel and as a vessel under 20 meters you shall not impede the passage of a vessel that can safely navigate only within the channel, and as a crossing vessel you must not cross if the crossing would impede her . If she is in doubt as to your intention, Inland requires her to use the Rule 34(d) signal, while International says she may COLREGs Rule 9(d).

(Both International & Inland) You are proceeding along a narrow channel. Which side do you favour, and how strong is the requirement?

Keep as near to the outer limit of the channel or fairway lying on your starboard side as is safe and practicable COLREGs Rule 9(a). The qualifier matters on a multiple-choice option: the requirement is not absolute, and the standard is what is safe and practicable .

(Both International & Inland) Your engine needs attention and the only sheltered water within reach is a narrow channel. May you anchor there?

Rule 9(g) requires any vessel, if the circumstances of the case admit, to avoid anchoring in a narrow channel COLREGs Rule 9(g). The obligation is qualified by whether circumstances admit, which is the phrase the exam expects you to recognise rather than a flat prohibition.