COLREG Rules 1–41: Summary + Free PDF
Brief study summaries of COLREG Rules 1–41, grouped by Part. Download the free printable PDF or read every summary below. This is a study aid, not the official IMO text or the complete annexes.
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A
Part A — General
1–3- 1ApplicationCOLREG applies to all vessels on the high seas and in connected waters navigable by seagoing vessels, subject to closely conforming local special rules and IMO-adopted traffic separation schemes.Quiz
- 2ResponsibilityNothing in these Rules shall exonerate any vessel from the consequences of neglecting these Rules or neglecting any precaution required by ordinary practice of seamanship.Quiz
- 3General DefinitionsDefines key terms used throughout the COLREGs including vessel, power-driven vessel, sailing vessel, restricted visibility, and more.Quiz
B
Part B — Steering & Sailing Rules
4–19Section I.Conduct in any condition of visibility
- 4ApplicationRules in Section I apply in any condition of visibility.Quiz
- 5Look-outKeep watch at all times with your eyes and ears, and use radar, AIS and every other means on board to judge the situation and the risk of collision.Quiz
- 6Safe SpeedAlways go slowly enough that you can still avoid a collision and stop in time, judged against visibility, traffic, manoeuvrability and conditions.Quiz
- 7Risk of CollisionEvery vessel shall use all available means to determine if risk of collision exists. If in doubt, such risk shall be deemed to exist.Quiz
- 8Action to Avoid CollisionWhen you act to avoid a collision, act early and make the change large enough for the other vessel to see, then check that it is working.Quiz
- 9Narrow ChannelsIn a narrow channel, stay on the starboard side as far as it is safe, and don't block vessels that can only navigate inside it.Quiz
- 10Traffic Separation SchemesIn a traffic separation scheme, follow your lane in the direction of the traffic, cross it at right angles if you must, and keep clear of the separation zone.Quiz
Section II.Conduct in sight of one another
- 11ApplicationRules 11 to 18 cover vessels that can see each other with their own eyes, not only on radar.Quiz
- 12Sailing VesselsWhen two sailing vessels approach, the one with wind on port side keeps clear. When both have wind on same side, the windward vessel keeps clear.Quiz
- 13OvertakingIf you are overtaking, it is your job to keep clear of the vessel ahead until you are past and well clear, whatever type of vessel you are.Quiz
- 14Head-on SituationWhen two power-driven vessels in sight meet on reciprocal or nearly reciprocal courses with risk of collision, each shall alter to starboard to pass port to port.Quiz
- 15Crossing SituationWhen two power-driven vessels are crossing, the vessel which has the other on her starboard side shall keep out of the way.Quiz
- 16Action by Give-way VesselAs the give-way vessel, make your move early and make it big, so you pass at a safe distance and the other vessel can see what you are doing.Quiz
- 17Action by Stand-on VesselThe stand-on vessel shall keep her course and speed, but may take action when it becomes apparent the give-way vessel is not acting.Quiz
- 18Responsibilities Between VesselsRule 18 sets the basic responsibilities between vessel types. Constrained-by-draught vessels receive special consideration but are not simply another rung in a fixed hierarchy.Quiz
C
Part C — Lights & Shapes
20–31- 20Application (Lights)Show your navigation lights between sunset and sunrise and whenever visibility is poor, and day shapes during the day.Quiz
- 21Definitions (Lights)Defines masthead light, sidelights, sternlight, towing light, all-round light and flashing light.Quiz
- 22Visibility of LightsSpecifies minimum visibility ranges for lights based on vessel length.Quiz
- 23Power-driven Vessels UnderwayPower-driven vessels underway shall exhibit masthead light(s), sidelights, and sternlight. Vessels 50m+ require two masthead lights.Quiz
- 24Towing and PushingVessels towing or pushing display additional masthead lights and a yellow towing light. Three masthead lights if tow exceeds 200m.Quiz
- 25Sailing Vessels Underway and Vessels Under OarsSailing vessels show sidelights and sternlight. May optionally show red over green all-round lights at the masthead.Quiz
- 26Fishing VesselsFishing vessels show green over white when trawling, red over white for other fishing, and sidelights plus sternlight when making way.Quiz
- 27Vessels Not Under Command or Restricted in Ability to ManoeuvreNUC shows two red all-round lights vertically. RAM shows red-white-red all-round lights vertically.Quiz
- 28Vessels Constrained by Their DraughtA vessel limited by her draught can add three red all-round lights, one above the other, or a black cylinder by day.Quiz
- 29Pilot VesselsA pilot vessel on duty shows white over red all-round lights at the masthead. When underway, also sidelights and sternlight.Quiz
- 30Anchored Vessels and Vessels AgroundAnchored vessels show an all-round white light forward and another aft (lower). Vessels aground additionally show two red all-round lights.Quiz
- 31SeaplanesWhere it is impracticable for a seaplane to exhibit lights of the exact characteristics, it shall exhibit lights as closely similar as possible.Quiz
D
Part D — Sound & Light Signals
32–37- 32Definitions (Sound Signals)Whistle = any Annex III-compliant sound appliance. Short blast ≈ 1 s. Prolonged blast = 4-6 s. Get the duration wrong and the meaning changes.Quiz
- 33Equipment for Sound SignalsWhistle from 12 m, bell added from 20 m, gong added from 100 m — and the gong's tone must not be confused with the bell's.Quiz
- 34Manoeuvring and Warning SignalsOne short blast means starboard, two means port, three means astern propulsion, and five or more rapid blasts mean doubt or danger.Quiz
- 35Sound Signals in Restricted VisibilityIn restricted visibility, power-driven vessels making way sound one prolonged blast every 2 minutes. Vessels not making way sound two prolonged blasts.Quiz
- 36Signals to Attract AttentionTo get another vessel's attention you can use a light or sound signal, as long as it can't be confused with any signal the rules define.Quiz
- 37Distress SignalsWhen in distress and requiring assistance, vessels shall use the signals described in Annex IV (red flares, SOS, MAYDAY, DSC, EPIRB and others).Quiz
E
Part E — Exemptions
38–38F
Part F — Verification of Compliance
39–41- 39Definitions (Verification of Compliance)Defines the terms used by Part F: audit, Audit Scheme, Code for Implementation and audit standard — the vocabulary of the IMO Member State Audit Scheme.Quiz
- 40Application (Verification of Compliance)Contracting Parties shall use the Code for Implementation when carrying out their obligations and responsibilities under the Convention.Quiz
- 41Verification of ComplianceEvery Contracting Party is subject to periodic IMO audits verifying its compliance with and implementation of the Convention.Quiz