NavCraft

The course

All 41 COLREG rules and 4 annexes, each in one sentence

These are the essences NavCraft opens each lesson with: what every rule of the International Regulations for Preventing Collisions at Sea (COLREG 1972) asks of you, in a sentence. In the app each one is followed by an animated situation, seamanship notes, the official text and a check.

Part A · General

  1. Rule 1. Application Free

    COLREG binds every vessel on the high seas and in all connected waters navigable by seagoing ships; local rules, extra signals and special-ship exemptions only adjust it.

  2. Rule 2. Responsibility Free

    Keeping the letter of the Rules never excuses bad seamanship; depart from a rule only when that is necessary to avoid immediate danger.

  3. Rule 3. General definitions Free

    A vessel’s status — power, sail, fishing, NUC, RAM, CBD, underway — comes from what she is doing right now, and every duty in the Rules flows from it.

Part B · Section I — Conduct of vessels in any condition of visibility

  1. Rule 4. Application

    Rules 4–10 — look-out, safe speed, risk, action, channels and schemes — apply in any visibility: clear day, dark night or thick fog.

  2. Rule 5. Look-out Free

    Every vessel, at all times, keeps a proper look-out by sight, hearing and every available means — to fully appraise the situation and the risk of collision.

  3. Rule 6. Safe speed Free

    Proceed at all times at a speed that lets you take proper and effective action to avoid collision and stop within a distance suited to the conditions.

  4. Rule 7. Risk of collision Free

    Use every available means to decide whether risk of collision exists; if in doubt, it exists — and a steady compass bearing of an approaching vessel means it does.

  5. Rule 8. Action to avoid collision Free

    Act early, act big, keep checking: action must be positive, in ample time, readily apparent, give a safe passing distance, and be monitored until finally past and clear.

  6. Rule 9. Narrow channels

    In a narrow channel keep to the starboard side, leave room for ships that can only use the channel, and signal when overtaking and at blind bends.

  7. Rule 10. Traffic separation schemes

    Follow your lane with the flow, join or leave at a small angle, cross on a heading at right angles — and remember every other rule still applies.

Part B · Section II — Conduct of vessels in sight of one another

  1. Rule 11. Application

    Section II — overtaking, head-on, crossing, stand-on and give-way, and the Rule 18 pecking order — applies only to vessels that can see each other.

  2. Rule 12. Sailing vessels

    Between two sailing vessels: port tack keeps clear of starboard tack; on the same tack the windward vessel keeps clear; a port-tacker unsure of a windward boat keeps clear.

  3. Rule 13. Overtaking

    Any vessel coming up from more than 22.5° abaft another's beam is overtaking and keeps out of the way until finally past and clear — whatever her type.

  4. Rule 14. Head-on situation

    Two power-driven vessels meeting end-on or nearly end-on with risk of collision both alter to starboard and pass port to port; in doubt, treat it as head-on.

  5. Rule 15. Crossing situation

    When two power-driven vessels cross with risk of collision, the one with the other on her own starboard side keeps out of the way and avoids crossing ahead.

  6. Rule 16. Action by give-way vessel

    Every vessel directed to keep out of the way shall, so far as possible, take early and substantial action to keep well clear.

  7. Rule 17. Action by stand-on vessel

    The stand-on vessel shall keep course and speed, may act once the give-way vessel clearly isn't acting, and shall act when the give-way vessel alone cannot avoid collision.

  8. Rule 18. Responsibilities between vessels

    In sight, and except where Rules 9, 10 and 13 say otherwise, the more manoeuvrable vessel keeps clear of the less: power → sailing → fishing → NUC/RAM.

Part B · Section III — Conduct of vessels in restricted visibility

  1. Rule 19. Conduct of vessels in restricted visibility

    Not in sight, in or near restricted visibility, nobody stands on: safe speed, early action on radar contacts, no forbidden turns, and slow right down for fog signals ahead.

Part C · Lights and shapes

  1. Rule 20. Application

    Lights from sunset to sunrise and in restricted visibility, shapes by day, in all weathers — and no other light that could be mistaken for them or blind the look-out.

  2. Rule 21. Definitions

    Six lights defined by colour and arc: masthead 225°, each sidelight 112.5°, sternlight and towing light 135°, all-round 360°, and flashing at 120 or more per minute.

  3. Rule 22. Visibility of lights

    Every light has a minimum range set by the vessel's length — the masthead light always reaches farthest, and only a small craft's sidelights drop to one mile.

  4. Rule 23. Power-driven vessels underway

    A power-driven vessel underway shows a masthead light, a second higher one aft if 50 m or more, sidelights and a sternlight — making way or not.

  5. Rule 24. Towing and pushing

    Towing: two masthead lights in a vertical line (three if the tow exceeds 200 m), sidelights, sternlight and a yellow towing light; pushing ahead drops the towing light.

  6. Rule 25. Sailing vessels underway and vessels under oars

    A sailing vessel shows sidelights and a sternlight but no masthead light; she may use a tricolour if under 20 m, or red over green — never both.

  7. Rule 26. Fishing vessels

    Trawling: green over white; other fishing: red over white. Sidelights and sternlight only when making way, two cones apex to apex by day, and no anchor lights.

  8. Rule 27. Vessels not under command or restricted in their ability to manoeuvre

    Not under command: two all-round reds, two balls. Restricted in ability to manoeuvre: red-white-red, ball-diamond-ball. Dredgers, divers and mine clearance vessels add their own signals.

  9. Rule 28. Vessels constrained by their draught

    A vessel constrained by her draught may add three all-round red lights in a vertical line, or a cylinder by day, to her normal power-driven lights.

  10. Rule 29. Pilot vessels

    On pilotage duty: white over red at the masthead, plus sidelights and sternlight underway or anchor signals at anchor; off duty, lit like any similar vessel.

  11. Rule 30. Anchored vessels and vessels aground

    At anchor: an all-round white forward and a lower one aft (one is enough under 50 m), or one ball by day; aground: add two reds, or three balls.

  12. Rule 31. Seaplanes

    A seaplane or WIG craft that cannot show the standard lights and shapes shows the closest possible equivalent in characteristics and position.

Part D · Sound and light signals

  1. Rule 32. Definitions

    A whistle is any sound appliance meeting Annex III; a short blast lasts about one second and a prolonged blast four to six seconds.

  2. Rule 33. Equipment for sound signals

    Whistle from 12 m, a bell as well from 20 m, a gong as well from 100 m; under 12 m, some other means of making an efficient sound signal.

  3. Rule 34. Manoeuvring and warning signals

    When in sight, a power-driven vessel announces each manoeuvre on her whistle; vessels also signal doubt and narrow-channel overtaking, and sound one prolonged blast approaching a blind bend.

  4. Rule 35. Sound signals in restricted visibility

    In or near restricted visibility, vessels identify themselves by sound: whistle at least every 2 minutes when underway; bell (and gong) at least every minute when anchored or aground.

  5. Rule 36. Signals to attract attention

    Any vessel may attract attention by light or sound, or by aiming a searchlight at the danger, provided nothing can be mistaken for another signal or a navigation aid.

  6. Rule 37. Distress signals

    A vessel in distress and requiring assistance shall use or exhibit the signals described in Annex IV — not improvised ones.

Part E · Exemptions

  1. Rule 38. Exemptions

    Ships built to the 1960 Rules before COLREG 1972 came into force got time-limited or permanent exemptions from some light and sound-appliance requirements.

Part F · Verification of compliance

  1. Rule 39. Definitions

    Part F defines the terms of IMO's audit of States: audit, the IMO Member State Audit Scheme, and the III Code, which is the audit standard.

  2. Rule 40. Application

    Contracting Parties shall use the III Code when carrying out their obligations and responsibilities under COLREG.

  3. Rule 41. Verification of compliance

    Every Contracting Party is periodically audited by IMO against the III Code; the Secretary-General administers the scheme, and the audited State must facilitate it and act on findings.

Annexes I–IV

  1. Annex I. Positioning and technical details of lights and shapes

    Annex I fixes where lights go, how bright they are and how big shapes are, so heights, spacings and sectors let you read length, aspect and status at a glance.

  2. Annex II. Additional signals for fishing vessels fishing in close proximity

    Trawlers fishing close to others add a lower pair — white-white shooting, white-red hauling, red-red net fast — and purse seiners hampered by gear may show alternately flashing yellows.

  3. Annex III. Technical details of sound signal appliances

    Bigger ships get deeper, louder whistles heard farther — about 2 miles at 200 m or more, half a mile under 20 m; bells and gongs need 110 dB.

  4. Annex IV. Distress signals

    Fifteen signals, used together or separately, mean distress and need of assistance; using them, or anything confusable with them, for any other purpose is prohibited.

Learn each rule properly

Seven of these lessons are free in NavCraft, and a 7-day trial opens the rest.

Download on the App Store