Narrow channels and traffic lanes (Rules 9 and 10)

Navigation Rules, lights & bridges · Power & sail

In a narrow channel or fairway, keep to the starboard side. A boat under 20 meters (65.6 ft), and any sailing vessel, must not impede a vessel that can navigate only within the channel. Similar duties apply in traffic separation schemes. The Inland Rules add stricter signal duties and a downbound rule on rivers.

Keeping right and staying out of the way

• Keep as near to the outer edge of the channel or fairway on your starboard side as is safe and practicable (Rule 9(a)).
• A vessel under 20 meters (65.6 ft), or any sailing vessel, must not impede the passage of a vessel that can safely navigate only within the channel (Rule 9(b)). For most recreational boats, that means leaving the channel to ships and tows.
• A vessel engaged in fishing must not impede any other vessel navigating within the channel (Rule 9(c)).
• Don't cross a narrow channel if doing so impedes a vessel confined to it. Under the Inland Rules that vessel must sound the danger signal if in doubt about your intentions; under the COLREGS it may (Rule 9(d)).

Overtaking, bends and anchoring

• COLREGS: if you can overtake only when the vessel ahead moves over, signal 2 prolonged + 1 short (to pass her starboard side) or 2 prolonged + 2 short (her port side). She agrees with prolonged, short, prolonged, short (Rule 9(e), 34(c)).
• Inland: a power-driven vessel overtaking another sounds 1 short (her starboard side) or 2 short (her port side). The overtaken vessel repeats the signal if she agrees, or sounds the danger signal if in doubt (Inland Rules 9(e), 34(c)).
• Agreement doesn't shift the burden: the overtaking vessel still has to keep clear under Rule 13 (Rule 9(e)(ii)).
• Nearing a bend or obstruction that could hide other vessels, go with particular care and sound one prolonged blast (Rule 9(f), 34(e)).
• If circumstances allow, avoid anchoring in a narrow channel (Rule 9(g)).

Inland: downbound vessels on rivers

• On the Great Lakes, Western Rivers and the waters listed in 33 CFR 89.25, a power-driven vessel downbound with a following current has the right-of-way in a narrow channel. It proposes how and where to pass and signals first; the upbound vessel holds as needed (Inland Rule 9(a)(ii)).
• The same downbound right-of-way applies to head-on meetings on those waters (Inland Rule 14(d)). The listed waters are named in 33 CFR 89.25, starting with the Tennessee-Tombigbee Waterway.

Traffic separation schemes (Rule 10)

• In a traffic separation scheme, use the correct lane in the general direction of traffic flow, keep clear of the separation line or zone, and normally join or leave at the ends of a lane, otherwise at as small an angle as practicable (Rule 10(b)).
• If you must cross the lanes, cross on a heading as close to a right angle to the traffic flow as practicable (Rule 10(c)).
• A vessel under 20 meters (65.6 ft) or a sailing vessel must not impede a power-driven vessel following a lane. Such vessels may use the inshore traffic zone (Rule 10(d), (j)).
• If you aren't using the scheme, avoid it by as wide a margin as practicable, and avoid anchoring in it or near its ends (Rule 10(g), (h)).

The rules: COLREGS Rule 9 · Inland Rule 9 · COLREGS Rule 10 · Inland Rule 10 · 33 CFR 83.09 · 33 CFR 83.10 · 33 CFR 89.25 · COLREGS Rule 34 · Inland Rule 34

A plain-language summary of federal rules for recreational boats, checked against the rules’ own text and a second source, and written in our own words. It isn’t legal advice. States add rules of their own, and rules change — the links above go to the current official text.