COLREGs Rule 9: Vessel conduct in narrow channels and fairways
Last reviewed: October 14, 2026
Rule 9 covers how vessels behave in narrow channels and fairways. A vessel proceeding along the channel must keep as near to the outer limit on her starboard side as is safe and practicable. The International and Inland rules differ on crossing signals, overtaking and downbound right-of-way.
Applies toVessels proceeding along, crossing, overtaking in, or anchoring in a narrow channel or fairway.
What it says
A vessel proceeding along the course of a narrow channel or fairway must keep as near to the outer limit on her starboard side as is safe and practicable.
COLREGs Rule 9(a)“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.”
Inland: A downbound power-driven vessel with a following current on the Great Lakes, Western Rivers, or waters specified by the Secretary has the right-of-way over an upbound vessel.
COLREGs Rule 9(a)(ii)“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”
A vessel of less than 20 meters in length or a sailing vessel must not impede the passage of a vessel that can safely navigate only within a narrow channel or fairway.
COLREGs Rule 9(b)“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.”
A vessel engaged in fishing must not impede the passage of any other vessel navigating within a narrow channel or fairway.
COLREGs Rule 9(c)“A vessel engaged in fishing shall not impede the passage of any other vessel navigating within a narrow channel or fairway.”
Inland: The vessel that can safely navigate only within the channel must use the signal prescribed in Rule 34(d) if in doubt about the crossing vessel's intention.
COLREGs Rule 9(d)“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.”
Inland: A power-driven vessel intending to overtake another power-driven vessel must sound the appropriate Rule 34(c) signal and take steps to permit safe passing.
COLREGs Rule 9(e)(i)“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)”
A vessel nearing a bend or an area where other vessels may be obscured must navigate with particular alertness and caution and sound the appropriate Rule 34(e) signal.
COLREGs Rule 9(f)“shall navigate with particular alertness and caution and shall sound the appropriate signal prescribed in Rule 34(e)”
Any vessel must avoid anchoring in a narrow channel if the circumstances of the case admit.
COLREGs Rule 9(g)“Any vessel shall, if the circumstances of the case admit, avoid anchoring in a narrow channel.”
Common questions
Which side of a narrow channel should a vessel keep to?
A vessel proceeding along the channel must keep as near to the outer limit on her starboard side as is safe and practicable.
“shall keep as near to the outer limit of the channel or fairway which lies on her starboard side as is safe and practicable.”
Can I anchor in a narrow channel?
Any vessel must avoid anchoring in a narrow channel if the circumstances of the case admit.
“Any vessel shall, if the circumstances of the case admit, avoid anchoring in a narrow channel.”
Can a fishing vessel impede other traffic in a narrow channel?
No. A vessel engaged in fishing must not impede the passage of any other vessel navigating within a narrow channel or fairway.
“A vessel engaged in fishing shall not impede the passage of any other vessel navigating within a narrow channel or fairway.”
Does Rule 9 relieve an overtaking vessel of its duties under Rule 13?
No. Rule 9 does not relieve the overtaking vessel of her obligation under Rule 13.
“This Rule does not relieve the overtaking vessel of her obligation under”
The text of COLREGs Rule 9
U.S. Coast Guard, Navigation Rules and Regulations Handbook
Rule 9: Narrow Channels
International (COLREGs)
(a) 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.
(b) A vessel of less than 20 meters in length or a sailing vessel shall not impede the passage of a vessel which can safely navigate only within a narrow channel or fairway.
(c) A vessel engaged in fishing shall not impede the passage of any other vessel navigating within a narrow channel or fairway.
(d) A vessel shall 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 may use the sound signal prescribed in Rule 34(d) if in doubt as to the intention of the crossing vessel.
(e) (i) In a narrow channel or fairway when overtaking can take place only if the vessel to be overtaken has to take action to permit safe passing, the vessel intending to overtake shall indicate her intention by sounding the appropriate signal prescribed in Rule 34(c)(i). The vessel to be overtaken shall, if in agreement, sound the appropriate signal prescribed in Rule 34(c)(ii) and take steps to permit safe passing. If in doubt she may sound the signals prescribed in Rule 34(d).
(ii) This Rule does not relieve the overtaking vessel of her obligation under Rule 13.
(f) 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).
(g) Any vessel shall, if the circumstances of the case admit, avoid anchoring in a narrow channel.
Inland Rules
Narrow channels
(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.
(ii) 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.
(b) 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.
(c) A vessel engaged in fishing shall not impede the passage of any other vessel navigating within a narrow channel or fairway.
(d) A vessel shall not cross a narrow channel or fairway if such crossing impedes the passage of a vessel which can safely navigate only within that 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)).
(ii) This Rule does not relieve the overtaking vessel of her obligation under Rule 13 (§ 83.13).
(f) 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)).
(g) Any vessel shall, if the circumstances of the case admit, avoid anchoring in a narrow channel. ‡ See 33 CFR 89.25, provided for reference on page 145 of this handbook.
Sections it refers to
The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of August 12, 2024. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.