The Rules at a Glance
Every rule in one line, for finding the governing rule fast and for revision. A line is a reminder, not the rule: each rule name links to its analysis in Part II, and text links to the rule word for word, annotated, in Appendix B.
Part A: General
Rule 1: Application · The Rules apply to all vessels on the high seas and every connected water navigable by seagoing vessels; local rules may sit on top, conforming as closely as possible. text
Rule 2: Responsibility · Compliance is a floor: good seamanship binds beyond the text, and departure is required when special circumstances and immediate danger together demand it. text
Rule 3: Definitions · The vocabulary that switches the other rules on: underway, in sight, and the vessel classes all live here. text
Part B, Section I: Any visibility
Rule 4: Application · Section I applies in every state of visibility and never switches off. text
Rule 5: Look-out · A proper look-out by sight, hearing and all available means, at all times. text
Rule 6: Safe speed · A speed at which you can take effective action and stop in time, judged by the listed factors; no number is given on purpose. text
Rule 7: Risk of collision · Use all available means; a steady compass bearing with closing range means risk, and any doubt means risk. text
Rule 8: Action to avoid collision · Act positively, early and large enough to be seen; achieve a safe passing distance; slacken speed or stop if you must. text
Rule 9: Narrow channels · Keep to starboard; small, sailing and fishing vessels do not impede a vessel confined to the channel; sound one prolonged blast at a blind bend. text
Rule 10: Traffic separation schemes · Follow the lane’s flow, join and leave at small angles, cross on a heading near right angles; every other rule still applies in full. text
Part B, Section II: In sight of one another
Rule 11: Application · Section II applies only to vessels in sight of one another, by eye and never by radar alone. text
Rule 12: Sailing vessels · Port tack gives way; on the same tack, windward gives way; unsure of the other’s tack, assume you give way. text
Rule 13: Overtaking · Coming up more than 22.5° abaft her beam, you keep clear, notwithstanding everything else, until finally past and clear; in doubt, assume you are overtaking. text
Rule 14: Head-on · Meeting on reciprocal or nearly reciprocal courses, both alter to starboard and pass port to port; in doubt, assume head-on. text
Rule 15: Crossing · The vessel with the other on her own starboard side keeps out of the way, and avoids crossing ahead. text
Rule 16: The give-way vessel · Early and substantial action to keep well clear. text
Rule 17: The stand-on vessel · Keep course and speed; may act when the give-way vessel plainly is not acting; must act when her action alone can no longer avoid collision; do not alter to port for a vessel on your own port side. text
Rule 18: Responsibilities between vessels · The order of who keeps clear of whom, except where Rules 9, 10 and 13 require otherwise; a vessel constrained by her draught is not in the order, her safe passage is simply not to be impeded. text
Part B, Section III: Restricted visibility
Rule 19: Restricted visibility · No give-way and no stand-on; safe speed with engines ready; avoid altering to port for a contact forward of the beam (unless overtaken) or toward one abaft the beam; a fog signal forward means slow to steerage way. text
Part C: Lights and shapes
Rule 20: Application · Lights from sunset to sunrise and in restricted visibility; shapes by day; nothing may be shown that could be mistaken for a prescribed light. text
Rule 21: Definitions · The arcs: masthead 225°, each sidelight 112.5°, sternlight 135°; the sternlight arc is exactly the overtaking sector. text
Rule 22: Visibility of lights · The minimum ranges lights must show, scaled by vessel length. text
Rule 23: Power-driven vessels underway · Masthead light (a second one abaft on 50 m or more), sidelights and a sternlight. text
Rule 24: Towing and pushing · Extra masthead lights in a line, a towing light aft, and a diamond when the tow runs long; the tow lights herself too. text
Rule 25: Sailing vessels and vessels under oars · Sidelights and sternlight, optional red-over-green; a motor-sailer is power-driven and shows a cone, apex down. text
Rule 26: Fishing vessels · Trawling green-over-white, other fishing red-over-white, with gear signals; underway or at anchor alike. text
Rule 27: Not under command; restricted in ability to manoeuvre · Red-over-red not under command; red-white-red restricted; dredgers add the pass-this-side signal. text
Rule 28: Constrained by her draught · Three all-round reds, or a cylinder by day; she remains a power-driven vessel. text
Rule 29: Pilot vessels · White over red, pilot ahead, on duty only. text
Rule 30: Anchored and aground · All-round white and a ball at anchor; aground adds red-over-red and three balls. text
Rule 31: Seaplanes · Comply as closely as possible where full compliance is impossible. text
Part D: Sound and light signals
Rule 32: Definitions · Whistle; a short blast is about one second, a prolonged blast four to six. text
Rule 33: Equipment · The sound equipment each length of vessel must carry. text
Rule 34: Manoeuvring and warning signals · One short, altering to starboard; two, to port; three, astern propulsion; five or more, doubt; plus the overtaking-agreement and blind-bend signals. text
Rule 35: Sound signals in restricted visibility · One prolonged making way; two prolonged stopped; one prolonged and two short for the hampered classes; bell, and gong aft, at anchor and aground. text
Rule 36: Signals to attract attention · Any light or sound that cannot be mistaken for a prescribed signal, and no searchlight into another bridge. text
Rule 37: Distress signals · In distress, use the Annex IV signals. text
Parts E and F: Exemptions and verification
Rule 38: Exemptions · Transitional relief for vessels built before the Rules or their amendments; a matter for owners and builders. text
Rule 39: Definitions · The terms of the flag-state audit regime. text
Rule 40: Application · Applies the verification provisions to flag states, not to vessels. text
Rule 41: Verification of compliance · The audit machinery by which a flag state shows it gives effect to the Convention; never applied on a bridge. text