International Regulations for Avoiding Collisions at Sea or IRPCS. The rules are specified in great detail in the regulations and the serious student is encouraged to seek the definitive document. Certain individuals are legally required to carry or possess a copy of the rules, such as the owners and/or operators of certain vessels. These legal requirements vary by jurisdiction. Consult the appropriate maritime authorities for each jurisdiction. Any individual subject to such requirements should obtain a complete, official copy from a government or official source. However, the rules are summarized below.
Part A - General
Part B - Steering and Sailing Rules
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
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
Section III - Conduct of Vessels in Restricted Visibility
- 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 Maneuver
(a) A vessel not under command shall exhibit:
(i) two all-round red lights in a vertical line where they can best be seen;
(ii) two balls or similar shapes in a vertical line where they can best be seen;
(iii) when making way through the water, in addition to the lights prescribed in this paragraph, sidelights and a sternlight.
(b) A vessel restricted in her ability to maneuver, except a vessel engaged in mineclearance operations, shall exhibit:
(i) three all-round lights in a vertical line where they can best be seen. The highest and lowest of these lights shall be red and the middle light shall be white;
(ii) three shapes in a vertical line where they can best be seen. The highest and lowest of these shapes shall be balls and the middle one a diamond;
(iii) when making way through the water, a masthead light, sidelights and a sternlight in addition to the lights prescribed in subparagraph (i);
(iv) when at anchor, in addition to the lights or shapes prescribed in subparagraphs(i) and (ii), the light, lights, or shape prescribed in Rule 30.
(c) A power driven vessel engaged in a towing operation such as severely restricts the towing vessel and her tow in their ability to deviate from their course shall, in addition to the lights or shapes prescribed in Rule 24(a), exhibit the lights or shapes prescribed in subparagraph (b)(i) and (ii) of this Rule.
(d) A vessel engaged in dredging or underwater operations, when restricted in her ability to maneuver, shall exhibit the lights and shapes prescribed in subparagraphs (b)(i),(ii) and (iii) of this Rule and shall in addition when an obstruction exists, exhibit:
(i) two all-round red lights or two balls in a vertical line to indicate the side on which the obstruction exists;
(ii) two all-round green lights or two diamonds in a vertical line to indicate the side on which another vessel may pass;
(iii) when at anchor, the lights or shapes prescribed in this paragraph instead of the lights or shapes prescribed in Rule 30.
(e) Whenever the size of a vessel engaged in diving operations makes it impracticable to exhibit all lights and shapes prescribed in paragraph (d) of this Rule, the following shall be exhibited:
(i) Three all-round lights in a vertical line where they can best be seen. The highest and lowest of these lights shall be red and the middle light shall be white;
(ii) a rigid replica of the code flag “A” not less than 1 meter in height. Measures shall be taken to ensure its all-round visibility.
(f) A vessel engaged in mineclearance operations shall in addition to the lights prescribed for a power driven vessel in Rule 23 or to the light or shape prescribed for a vessel at anchor in Rule 30 as appropriate, exhibit three all-round green lights or three balls. One of these lights or shapes shall be exhibited near the foremast head and one at each end of the fore yard. These lights or shapes indicate that it is dangerous for another vessel to approach within 1000 meters of the mineclearance vessel.
(g) Vessels of less than 12 meters in length, except those engaged in diving operations, shall not be required to exhibit the lights prescribed in this Rule.
(h) The signals prescribed in this Rule are not signals of vessels in distress and requiring assistance. Such signals are contained in Annex IV to these Regulations.
- Rule 28 : Vessels Constrained by their Draft
- 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 : Maneuvering 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