The rules of the road
Plain-language study summaries of the steering, lights and sound rules. Open a card to read the key points and mark it studied.
Application
These Rules apply to all vessels upon the high seas and in all waters connected to them navigable by seagoing vessels. Local authorities may make special rules for harbours, rivers and inland waters, but those must conform as closely as possible to these Rules.
Responsibility
Nothing in these Rules exonerates any vessel, owner, master or crew from the consequences of neglecting the Rules or of neglecting any precaution required by the ordinary practice of seamen or the special circumstances of the case. A departure from the Rules is allowed where necessary to avoid immediate danger.
General definitions
Defines the terms used throughout: vessel, power-driven, sailing, engaged in fishing, seaplane, not under command, restricted in ability to manoeuvre, constrained by draught, underway, length and breadth, in sight of one another, restricted visibility and WIG craft.
Application (steering & sailing)
The rules of Section I of Part B apply in any condition of visibility — clear weather, fog or darkness alike.
Look-out
Every vessel shall at all times maintain a proper look-out by sight and hearing as well as by all available means appropriate to the prevailing circumstances, so as to make a full appraisal of the situation and of the risk of collision.
Safe speed
Every vessel shall at all times proceed at a safe speed so that she can take proper and effective action to avoid collision and be stopped within a distance appropriate to the prevailing circumstances and conditions.
Risk of collision
Every vessel shall use all available means to determine if risk of collision exists. If there is any doubt, such risk shall be deemed to exist. Risk exists when the compass bearing of an approaching vessel does not appreciably change.
Action to avoid collision
Action taken to avoid collision shall be positive, made in ample time and with due regard to good seamanship. Course or speed alterations should be large enough to be readily apparent to another vessel.
Narrow channels
A vessel proceeding along 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.
Traffic separation schemes
In a scheme adopted by the Organization, proceed in the appropriate lane in the general direction of flow, keep clear of the separation line or zone, join and leave at the ends or at a small angle, and cross on a heading as nearly as practicable at right angles to the flow.
Application (vessels in sight)
Rules 11 to 18 apply only to vessels in sight of one another.
Sailing vessels
When two sailing vessels approach so as to involve risk of collision: with wind on different sides, the one with wind on the port side keeps out of the way; with wind on the same side, the windward vessel keeps clear; if a vessel with wind to port sees a vessel to windward and cannot tell which side her wind is on, she keeps out of the way.
Overtaking
Any vessel overtaking any other shall keep out of the way of the vessel being overtaken. A vessel is overtaking when coming up with another from a direction more than 22.5° abaft her beam.
Head-on situation
When two power-driven vessels are meeting on reciprocal or nearly reciprocal courses so as to involve risk of collision, each shall alter her course to starboard so that each shall pass on the port side of the other.
Crossing situation
When two power-driven vessels are crossing so as to involve risk of collision, the vessel which has the other on her own starboard side shall keep out of the way and shall, if the circumstances admit, avoid crossing ahead of the other vessel.
Action by give-way vessel
Every vessel which is directed to keep out of the way of another vessel shall, so far as possible, take early and substantial action to keep well clear.
Action by stand-on vessel
The stand-on vessel shall keep her course and speed. She may take action as soon as it becomes apparent the give-way vessel is not taking appropriate action, and shall take action when collision cannot be avoided by the give-way vessel alone.
Responsibilities between vessels
The pecking order: a power-driven vessel keeps clear of vessels not under command, restricted in ability to manoeuvre, engaged in fishing, and sailing vessels. A sailing vessel keeps clear of fishing vessels, RAM and NUC. A fishing vessel keeps clear of RAM and NUC.
Restricted visibility
In or near an area of restricted visibility, every vessel shall proceed at a safe speed adapted to the conditions, have engines ready for immediate manoeuvre, and comply with the sound signals of Rule 35.
Application (lights & shapes)
Lights are exhibited from sunset to sunrise in all weathers, and in restricted visibility by day as well; shapes are exhibited by day. The rules on lights are complied with in all weathers.
Definitions — lights
Definitions of the navigation lights: masthead light (white, 225°), sidelights (green starboard, red port, 112.5° each), sternlight (white, 135°), towing light (yellow, 135°), all-round light (360°) and flashing light (120+ flashes per minute).
Visibility of lights
Minimum ranges depend on vessel length: 50 m and over — masthead 6 miles, sidelights 3, stern/towing/all-round 3; 12 m to 50 m — masthead 5 (3 if under 20 m), sidelights 2, others 2; under 12 m — masthead 2, sidelights 1, others 2.
Power-driven vessels underway
A power-driven vessel underway shall exhibit a masthead light forward, sidelights and a sternlight. Vessels of 50 m or more carry a second masthead light abaft of and higher than the forward one.
Towing and pushing
A power-driven vessel when towing shows two masthead lights in a vertical line (three if the tow exceeds 200 m), sidelights, a sternlight and a yellow towing light above the sternlight. A tow over 200 m carries a diamond shape.
Sailing vessels & rowing
A sailing vessel underway shows sidelights and a sternlight — no masthead light. She may also show red over green all-round lights at the masthead. Small sailing vessels and boats under oars may show a white light or torch instead.
Fishing vessels
A vessel engaged in fishing shows all-round red over white; when trawling, all-round green over white. With outlying gear over 150 m she adds an all-round white light in the direction of the gear. 'Red over white, fishing at night.'
Not under command / restricted in ability
A vessel not under command shows two all-round red lights in a vertical line. A vessel restricted in her ability to manoeuvre shows all-round red–white–red in a vertical line, plus her normal underway lights when making way.
Vessels constrained by their draught
A vessel constrained by her draught may, in addition to the lights for a power-driven vessel, exhibit three all-round red lights in a vertical line, or a cylinder by day.
Pilot vessels
A vessel engaged on pilotage duty shows all-round white over red at the masthead — 'white over red, pilot ahead' — plus sidelights and sternlight when underway, or anchor lights when at anchor.
Anchored vessels & aground
A vessel at anchor shows an all-round white light forward (vessels of 50 m and over add a second aft, lower than the forward one). A vessel aground shows the anchor lights plus two all-round red lights in a vertical line.
Seaplanes
Where a seaplane or WIG craft cannot exhibit lights and shapes of the characteristics or in the positions prescribed, she shall exhibit lights and shapes as closely similar in characteristics and position as is possible.
Definitions (sound signals)
'Whistle' means any sound signalling appliance capable of producing the prescribed blasts and complying with Annex III. A short blast is about one second; a prolonged blast is four to six seconds.
Equipment for sound signals
A vessel of 12 m or more shall carry a whistle; of 20 m or more, a whistle and a bell; of 100 m or more, a gong in addition. A vessel of less than 12 m must carry some other efficient means of making a sound signal.
Manoeuvring & warning signals
In sight of one another: one short blast — altering to starboard; two short — to port; three short — operating astern propulsion. Five or more short blasts is the danger/doubt signal.
Sound signals in restricted visibility
In restricted visibility: a power-driven vessel making way sounds one prolonged blast at intervals of not more than 2 minutes; under way but stopped, two prolonged blasts. Sailing, fishing, NUC, RAM and towing vessels sound one prolonged followed by two short blasts.
Signals to attract attention
If necessary to attract the attention of another vessel, any light or sound signal that cannot be mistaken for a prescribed signal may be used, or a searchlight directed towards the danger — but not so as to embarrass any vessel.
Distress signals
Annex IV lists signals of distress: continuous fog-signal sounding, rockets or shells throwing red stars, SOS by any signalling method, red flares, orange smoke, slowly raising and lowering outstretched arms, and the square flag over or under a ball.
Exemptions
Vessels whose keel was laid before the Rules entered into force may be exempted, for stated periods, from certain requirements on light positioning, ranges, colour specifications, sound signal appliances and the repositioning of lights.