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
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 Maneuver
- Rule 28 : Vessels Constrained by their Draft
- Rule 29 : Pilot Vessels
- Rule 30 : Anchored Vessels and Vessels Aground
- Rule 31 : Seaplanes
- Rule 32 : Definitions
- Rule 33 : Equipment for Sound Signals
- Rule 34 : Maneuvering and Warning Signals
Rule 35 : Sound Signals in Restricted Visibility
In or near an area of restricted visibility, whether by day or night the signals prescribed in this Rule shall be used as follows: (a) A power driven vessel making way through the water shall sound at intervals of not more than 2 minutes one prolonged blast.
(b) A power driven vessel underway but stopped and making no way through the water shall sound at intervals of no more than 2 minutes two prolonged blasts in succession with an interval of about 2 seconds between them.
(c) A vessel not under command, a vessel restricted in her ability to maneuver, a vessel constrained by her draft, a sailing vessel, a vessel engaged in fishing and a vessel engaged in towing or pushing another vessel shall, instead of the signals prescribed in paragraph (a) or (b) of this Rule, sound at intervals of not more than 2 minutes three blasts in succession, namely one prolonged followed by two short blasts.
(d) A vessel engaged in fishing, when at anchor, and a vessel restricted in her ability to maneuver when carrying out her work at anchor, shall instead of the signals prescribed in paragraph (g) of this Rule sound the signal prescribed in paragraph (c) of this Rule.
(e) A vessel towed or if more than one vessel is being towed the last vessel of the tow, if manned, shall at intervals of not more than 2 minutes sound four blasts in succession, namely one prolonged followed by three short blasts. When practicable, this signal shall be made immediately after the signal made by the towing vessel.
(f) When a pushing vessel and a vessel being pushed ahead are rigidly connected in a composite unit they shall be regarded as a power driven vessel and shall give the signals prescribed in paragraphs (a) or (b) of this Rule.
(g) A vessel at anchor shall at intervals of not more than 1 minute ring the bell rapidly for five seconds. In a vessel 100 meters or more in length the bell shall be sounded in the forepart of the vessel and immediately after the ringing of the bell the gong shall be sounded rapidly for about 5 seconds in the after part of the vessel. A vessel at anchor may in addition sound three blasts in succession, namely one short, one long and one short blast, to give warning of her position and of the possibility of collision to an approaching vessel.
(h) A vessel aground shall give the bell signal and if required the gong signal prescribed in paragraph (g) of this Rule and shall, in addition, give three separate and distinct strokes on the bell immediately before and after the rapid ringing of the bell. A vessel aground may in addition sound an appropriate whistle signal.
(i) A vessel of less than 12 meters in length shall not be obliged to give the above mentioned signals but, if she does not, shall make some other efficient sound signal at intervals of not more than 2 minutes.
(j) A pilotage vessel when engaged on pilotage duty may in addition to the signals prescribed in paragraph (a), (b) or (g) of this Rule sound an identity signal consisting of four short blasts.
Part E - Exemptions
- Rule 38 : Exemptions