International Regulations for Prevention of Collisions at Sea – COLREG IRPCS – Collision Rules


Rule 1 – Application

Rule 2 – Responsibility

Rule 3 – General Definitions

PART B – Section I Conduct of Vessels in any Condition of Visibility

Rule 4 – Application

Rule 5 – Look-out

Rule 6 – Safe Speed

Rule 7 – Risk of Collision

Rule 8 – Action to Avoid Collision

Rule 9 – Narrow Channels

Rule 10 – Traffic Separation Schemes

PART B – Section II Conduct of Vessels in Sight of One Another

Rule 11 – Application

Rule 12 – Sailing Vessels

Rule 13 – Overtaking

Rule 14 – Head-on Situation

Rule 15 – Crossing Situation

Rule 16 – Action by Give-way Vessel

Rule 17 – Action by Stand-on Vessel

Rule 18 – Responsibilities Between Vessels

PART B – Section III Conduct of Vessels in Restricted Visibility

Rule 19 – Conduct of Vessels in Restricted Visibility

PART C – Lights and Shapes

Rule 20 – Application

Rule 21 – Definitions

Rule 22 – Visibility of Lights

Rule 23 – Power-driven Vessels Underway

Rule 24 – Towing and Pushing

Rule 25 – Sailing Vessels Underway and Vessels Under Oars

Rule 26 – Fishing Vessels

Rule 27 – Vessels Not Under Command or Restricted in their Ability to Manoeuvre

Rule 28 – Vessels Constrained by their Draught

Rule 29 – Pilot Vessels

Rule 30 – Anchored Vessels and Vessels Aground

Rule 31 – Seaplanes

PART D – Sound and Light Signals

Rule 32 – Definitions

Rule 33 – Equipment for Sound Signals

Rule 34 – Manoeuvring and Warning Signals

Rule 35 – Sound Signals in Restricted Visibility

Rule 36 – Signals to Attract Attention

Rule 37 – Distress Signals

PART E – Exemptions

Rule 38 – Exemptions

PART F – Verification of Compliance with the Provisions of the Convention

Rule 39 – Definitions

Rule 40 – Application

Rule 41 – Verification of Compliance

ANNEX I – Positioning and Technical Details of Lights and Shapes

ANNEX II Addition Signals for Fishing Vessels Fishing in Close Proximity

ANNEX III : Technical Details of Sound Signal Appliances

ANNEX IV Distress Signals


IRPCS – History

Prior to the development of a single set of international rules and practices, there existed separate practices and various conventions and informal procedures in different parts of the world, as advanced by various maritime nations. As a result, there were inconsistencies and even contradictions that gave rise to unintended collisions. Vessel navigation lights for operating in darkness as well as navigation marks also were not standardised, giving rise to dangerous confusion and ambiguity between vessels at risk of colliding.

With the advent of steam-powered ships in the mid-19th century, conventions for sailing vessel navigation had to be supplemented with conventions for power-driven vessel navigation. Sailing vessels are limited as to their manoeuvrability in that they cannot sail directly into the wind and cannot be readily navigated in the absence of wind. On the other hand, steamships can manoeuvre in all 360 degrees of direction and can be manoeuvred irrespective of the presence or absence of wind.

IRPCS – Implementation of the Rules and subsequent amendments 

The International Regulations for Preventing Collisions at Sea were adopted as a convention of the International Maritime Organization on 20 October 1972 and entered into force on 15 July 1977. They were designed to update and replace the Collision Regulations of 1960, particularly with regard to Traffic Separation Schemes (TSS) following the first of these, introduced in the Strait of Dover in 1967.

As of June 2013, the convention has been ratified by 155 states representing 98.7% of the tonnage of the world’s merchant fleets.

The international regulations have been amended several times since their first adoption. In 1981 Rule 10 was amended with regard to dredging or surveying in traffic separation schemes.

In 1987 amendments were made to several rules, including rule 1(e) for vessels of special construction; rule 3(h), vessels constrained by her draught and Rule 10(c), crossing traffic lanes.

In 1989 Rule 10 was altered to stop unnecessary use of the inshore traffic zones associated with TSS.

In 1993 amendments were made concerning the positioning of lights on vessels. In 2001 new rules were added relating to wing-in-ground-effect (WIG) craft and in 2007 the text of Annex IV (Distress signals) was rewritten.

The 2013 amendments (resolution A.1085(28)) Adoption: 4 December 2013 Entry into force: 1 January 2016 After existing part E (Exemptions), a new part F (Verification of compliance with the provisions of the Convention) is added in order for the Organization to make necessary verifications under the IMO Member State Audit Scheme.



You cannot copy content of this page