COLREGs Rule 9: Narrow Channels — Captain's Exam Prep

What does Rule 9 actually say?#

Source

Verbatim 33 CFR §83.09, public domain. The international COLREGs text is published by the IMO and cannot be reproduced here; this U.S. wording tracks it closely.

(a)(i) A vessel proceeding along the course of a narrow channel or fairway shall keep as near to the outer limit of the channel or fairway which lies on her starboard side as is safe and practicable.

Notwithstanding paragraph (a)(i) of this Rule and Rule 14(a) (§ 83.14(a)), a power-driven vessel operating in narrow channels or fairways on the Great Lakes, Western Rivers, or waters specified by the Secretary, and proceeding downbound with a following current shall have 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) (§ 83.34(a)(i)), as appropriate. The vessel proceeding upbound against the current shall hold as necessary to permit safe passing.

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A vessel of less than 20 meters in length or a sailing vessel shall not impede the passage of a vessel that can safely navigate only within a narrow channel or fairway.

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A vessel engaged in fishing shall not impede the passage of any other vessel navigating within a narrow channel or fairway.

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A vessel must not cross a narrow channel or fairway if such crossing impedes the passage of a vessel which can safely navigate only within such channel or fairway. The latter vessel must use the signal prescribed in Rule 34(d) (§ 83.34(d)) if in doubt as to the intention of the crossing vessel. (e)(i) In a narrow channel or fairway when overtaking, the power-driven vessel intending to overtake another power-driven vessel shall indicate her intention by sounding the appropriate signal prescribed in Rule 34(c) (§ 83.34(c)) and take steps to permit safe passing. The power-driven vessel being overtaken, if in agreement, shall sound 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) (§ 83.34(d)).

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This Rule does not relieve the overtaking vessel of her obligation under Rule 13 (§ 83.13).

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A vessel nearing a bend or an area of a narrow channel or fairway where other vessels may be obscured by an intervening obstruction shall navigate with particular alertness and caution and shall sound the appropriate signal prescribed in Rule 34(e) (§ 83.34(e)).

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Any vessel shall, if the circumstances of the case admit, avoid anchoring in a narrow channel. [USCG-2012-0102, 79 FR 37912, July 2, 2014, as amended by USCG-2015-0433, 80 FR 44280, July 27, 2015; USCG-2016-0498, 82 FR 35080, July 28, 2017]

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Notwithstanding paragraph (a)(i) of this Rule and Rule 14(a) (§ 83.14(a)), a power-driven vessel operating in narrow channels or fairways on the Great Lakes, Western Rivers, or waters specified by the Secretary, and proceeding downbound with a following current shall have 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) (§ 83.34(a)(i)), as appropriate. The vessel proceeding upbound against the current shall hold as necessary to permit safe passing.

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A vessel of less than 20 meters in length or a sailing vessel shall not impede the passage of a vessel that can safely navigate only within a narrow channel or fairway.

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A vessel engaged in fishing shall not impede the passage of any other vessel navigating within a narrow channel or fairway.

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A vessel must not cross a narrow channel or fairway if such crossing impedes the passage of a vessel which can safely navigate only within such channel or fairway. The latter vessel must use the signal prescribed in Rule 34(d) (§ 83.34(d)) if in doubt as to the intention of the crossing vessel. (e)(i) In a narrow channel or fairway when overtaking, the power-driven vessel intending to overtake another power-driven vessel shall indicate her intention by sounding the appropriate signal prescribed in Rule 34(c) (§ 83.34(c)) and take steps to permit safe passing. The power-driven vessel being overtaken, if in agreement, shall sound 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) (§ 83.34(d)).

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This Rule does not relieve the overtaking vessel of her obligation under Rule 13 (§ 83.13).

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A vessel nearing a bend or an area of a narrow channel or fairway where other vessels may be obscured by an intervening obstruction shall navigate with particular alertness and caution and shall sound the appropriate signal prescribed in Rule 34(e) (§ 83.34(e)).

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Any vessel shall, if the circumstances of the case admit, avoid anchoring in a narrow channel. [USCG-2012-0102, 79 FR 37912, July 2, 2014, as amended by USCG-2015-0433, 80 FR 44280, July 27, 2015; USCG-2016-0498, 82 FR 35080, July 28, 2017]

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Practice this rule#

One real exam question on this rule, cited to source. No sign-up.

Rule 9 — Narrow Channels

A vessel that can safely navigate only within a narrow channel is in doubt about the intentions of a vessel attempting to cross the channel ahead of her. Under the Inland Navigation Rules, what signal must the channel-bound vessel sound?

How does Inland Rule 9 differ from COLREGs?#

Inland Rule 9 grants descending-current vessels on the Great Lakes, Western Rivers, and waters specified by the Secretary the right of way over ascending vessels and lets them propose the manner of passage.

21 of 38 rules differ somewhere; the five the exam leans on are Rule 9, Rule 10, Rule 24, Rule 28 and Rule 34, side by side on Inland vs International Rules.

Why it shows up on the exam#

Inland adds a power-driven-vessel-on-the-Great-Lakes/Western-Rivers descending-favor exception in 33 CFR §83.09(a)(ii).

What does the exam actually test here?#

Where to steer
Starboard side of the channel
A vessel proceeding along the course of a narrow channel or fairway shall keep as near to the outer limit of the channel on her starboard side as is safe and practicable.
Who must not impede
Under 20 m, sail, fishing, crossing
A vessel under 20 metres or a sailing vessel shall not impede a vessel that can safely navigate only within the channel; a vessel engaged in fishing shall not impede any other vessel in the channel; and no vessel may cross the channel if the crossing impedes such a vessel.
Signals in the channel
Bends and overtaking
Nearing a bend where other vessels may be obscured, navigate with particular alertness and sound the Rule 34(e) signal. Overtaking in a narrow channel runs on the Rule 34(c) signal-and-agreement exchange, and does not relieve the overtaking vessel of Rule 13.

Rule 9 — common exam questions#

Which side of a narrow channel do you keep to?

As near to the outer limit of the channel or fairway on your starboard side as is safe and practicable (33 CFR §83.09(a)(i)).

Who has the right of way downbound on the Western Rivers?

Under the Inland rule, a power-driven vessel operating in a narrow channel on the Great Lakes, Western Rivers, or waters specified by the Secretary and proceeding downbound with a following current has the right of way over an upbound vessel. She proposes the manner and place of passage and initiates the Rule 34(a)(i) signals, and the upbound vessel holds as necessary to permit safe passing (33 CFR §83.09(a)(ii)). There is no COLREGs equivalent.

What signal do you sound approaching a blind bend?

The Rule 34(e) signal — one prolonged blast — sounded by a vessel nearing a bend or an area of a narrow channel where other vessels may be obscured by an intervening obstruction (33 CFR §83.09(f)).

Can a small vessel insist on right of way in a narrow channel?

No. A vessel of less than 20 metres in length or a sailing vessel shall not impede the passage of a vessel that can safely navigate only within a narrow channel or fairway (33 CFR §83.09(b)).

Can you anchor in a narrow channel?

Rule 9(g) says any vessel shall, if the circumstances of the case admit, avoid anchoring in a narrow channel.

Authoritative source#

33 CFR §83.09 — this section with its neighbours. 33 CFR Part 83 is public domain; checked 2026-05-16.
COLREGs Rule 9 is published by the IMO and is authoritative internationally.

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