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International Regulations for Preventing Collisions at Sea
International Regulations for Preventing Collisions at Sea
International Regulations for Preventing Collisions at Sea
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The International Regulations for Preventing Collisions at Sea 1972, also known as Collision Regulations (COLREG), are published by the International Maritime Organization (IMO) and set out, among other things, the "rules of the road" or navigation rules to be followed by ships and other vessels at sea to prevent collisions between two or more vessels.[1][2] COLREG can also refer to the specific political line that divides inland waterways, which are subject to their own navigation rules, and coastal waterways which are subject to international navigation rules. They are derived from a multilateral treaty called the Convention on the International Regulations for Preventing Collisions at Sea,[3] also known as Collision Regulations of 1960.[3]

Although rules for navigating vessels inland may differ, the international rules specify that they should be as closely in line with the international rules as possible. In most of continental Europe, the Code Européen des Voies de la Navigation Intérieure (CEVNI, or the European Code for Navigation on Inland Waters) apply. In the United States, the rules for vessels navigating inland are published alongside the international rules.[4]

Organization of the regulatory documents

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As of 2022, there are 41 Rules and four annexes in COLREGs Rules in force.[5]

PART A - GENERAL

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Rule 1 - Application.[6] This rule states that the COLREGs should be complied with by all vessels on the "high seas".[6]

Rule 2 – Responsibility.[6] This rule allows Master mariners and other persons in charge of vessels to depart from the rules to "avoid immediate danger", provided there are special circumstances for doing so.[6] The rule also effectively requires all navigators to exercise good seamanship in applying the rules.[6]

Rule 3 – General Definitions.[7] This rule sets out key definitions that apply to terms in the rest of the rules, including definitions for 'power-driven vessels', 'sailing vessels' and other terms such as 'not under command' and 'vessel restricted in her ability to manoeuvre.[7]

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

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Rule 4 – Application.[8] This rule states that the rules in this section apply to all vessels in any condition of visibility.[8]

Rule 5 – Look-out.[9] This rule concerns the keeping of a proper lookout to sea.[9] It involves keeping the lookout by all available means, including audible means, visual means and by the use of marine radar.[9]

Rule 6 – Safe Speed.[10] This rule sets out a requirement for all vessels to proceed at a safe speed with reference to the prevailing circumstances and conditions.[10] Relevant circumstances include, for example, the state of visibility, the presence of other ships (traffic), as well as the draught and manoeuvrability of the mariner's own ship.[10]

Rule 7 – Risk of Collision.[11] This rule requires all vessels to use all available means to determine if a risk of collision exists.[11] These include the proper use of marine radar and the taking of bearings by ship's compass to determine if there is a steady bearing and risk of collision.[11]

Rule 8 – Action to Avoid Collision.[12][13] This rule sets out requirements for vessels to alter course and/or speed to pass a safe distance with other vessels.[12] It requires alterations to be consistent with the concept of good seamanship, as well as be sufficient to be observed by the other vessel, i.e., a large and bold angle of course alteration.[12][13] The rule is designed to work in operation with other rules, including Rules 16 and 17.[13]

Rule 9 – Narrow Channels.[14] This rule concerns those vessels keeping a course within narrow channels and fairways.[14] It requires vessels less than 20 metres in length, fishing vessels and sailing vessels to not impede the passage of larger vessels in the narrow channel.[14] It also gives reference to signals (sound and light) that can be given to allow vessels to overtake one another if following the narrow channel or fairway, as well as a separate signal when approaching a bend.[14] Vessels are also not allowed to anchor unless there are legitimate circumstances for doing so.[14]

Rule 10 – Traffic Separation Schemes.[15] Typically abbreviated to TSS by mariners, these schemes aim to promote the safety of navigation by ensuring ships follow a general direction of travel within defined traffic lanes.[15] The TSS lanes are shown on paper and electronic charts and by monitoring their position, a ship can determine their navigation within the scheme.[15] Additionally, a TSS provides separation zones and inshore-traffic zones, to which restrictions apply.[15] Additional restrictions also apply to some vessel types, such as fishing vessels and vessels less than 20m in length to not impede the safe passage of other/larger vessels.[15]

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

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Rule 11 - Application

Rule 12 – Sailing Vessels.[16][17] The rule details how two or more sailing vessels should give way to each other when meeting.[16][17] This is based on the wind direction.[17] When each[16] sailing vessel has the wind on a different side, the vessel which has the wind on the port side should keep out of the way of the other.[16] Alternatively when both sailing vessels have the wind on the same side, the vessel which is to windward should keep out of the way of the vessel which is to leeward.[16] Finally, if a vessel with the wind on the port side sees a vessel to windward and cannot determine with certainty whether the other vessel has the wind on her port or starboard side, they should keep out of the way of the other, i.e. they take action to make the situation safe regardless of knowing for sure the wind situation of the other vessel.[16]

Rule 13 covers overtaking situations between vessels

Rule 13 – Overtaking.[18][19] This rule governs overtaking situations between different vessels.[19] The primary requirement is that for all overtaking vessels, they must keep clear of the vessels they are overtaking.[19] For sailing vessels Rule 13 also takes precedence over rules 12 and 18 meaning the overtaking sailing vessel must keep clear.[19]

Rule 14 – Head-on Situation.[20][21] This rule requires power-driven vessels that meet head-on i.e. bow directly facing another bow, to both alter course to starboard so as to pass clear of each other.[20][21] This is referred to as passing 'port to port' as the port sides separate away from each other as vessels alter.[20] The rule effectively assigns equal responsibility to vessels to prevent collision.[21]

Rule 15 – Crossing Situation.[22] This rule concerns actions for vessels in crossing situations and essentially requires a vessel that has another vessel on their starboard (right hand) side to stay out of the way of the other, becoming the give way vessel under rule 17.[22] The other vessel is required to stand-on under rule 17.[22] Also, if the circumstances of the case admit, the vessel that has the other on their starboard side should avoid crossing ahead of the other vessel.[23]

Rule 16 – Action by Give-way Vessel.[24] This rule requires the give-way vessel to take early and substantial action to keep well clear of the other vessel.[24]

Rule 17 – Action by Stand-on Vessel.[25] Rule 17 requires the stand-on vessel to maintain their course and speed.[25] However, if it appears that the other vessel who is required to give way is not taking action, then they may take action to avoid collision according to certain requirements having been met.[25]

Rule 18 – Responsibilities Between Vessels.[26][27] Rule 18 effectively establishes an order of priority between all vessels and modes of operation of those vessels.[26] For power-driven vessels operating normally, these types of vessels are required to keep clear of all other vessels, including sailing and fishing vessels.[27] However, where vessels are subject to restrictions such as not under command, constrained by draft or restricted in their ability manoeuvre, then other vessels, including other power-driven vessels, sailing vessels and fishing vessels are either required to keep out of the way or not impede their passage, depending on the requirements.[27]

PART B - Section III Conduct of Vessels in Restricted Visibility

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Rule 19 – Conduct of Vessels in Restricted Visibility.[28] This rule governs collision avoidance for vessels not in sight of another when navigating in or near an area of restricted visibility.[28] Causes include fog, smoke and other phenomena such as heavy precipitation. The rule requires all vessels to proceed at a safe speed adapted to the conditions and to effectively take action to avoid collision in ample time.[29] As far as possible, vessels should avoid altering to port for vessels forward of their beam unless being overtaken and avoid altering course towards a vessel abeam or abaft the beam.[29] For ships that have heard another vessels sound signal but not observed them on radar, part e requires the ship to reduce speed to the minimum required to maintain their course and if necessary to take all way off.[28]

PART C - Lights and Shapes

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Vessel shapes under the COLREGs

Rule 20 – Application

Rule 21 – Definitions

Rule 22 – Visibility of Lights.[30] The minimum visible distance requirements of navigational lights are detailed under this rule.[30] These vary according to the length of the vessel.[30] For example, for vessels greater than 50 metres in length, the visibility ranges of lights are 6 miles for masthead lights, 3 miles for sidelights, 3 miles for the sternlight, 3 miles for towing lights and 3 miles for an all round light.[30]

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

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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

Annexes

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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. The annex lists the official international distress signals.[31] These include signals such as the spoken word "Mayday", the Code flag Signal "N.C. (November Charlie)", flares showing red lights, "SOS" in morse code", an orange smoke signal and others.[31]

History

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Prior to the development of a single set of international rules and practices, separate practices and various conventions and informal procedures existed in different parts of the world.[32] As a result, there were inconsistencies and contradictions between navigation lights that gave rise to unintended collisions, including not least that many sailing vessels did not display navigation lights.[33] Vessel navigation lights for operating in darkness as well as navigation marks were also not standardised, giving rise to dangerous confusion and ambiguity between vessels resulting in collisions and groundings.[33]

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 are limited in the absence of wind. On the other hand, ships propelled by machinery can manoeuvre in all 360 degrees of direction and therefore can be manoeuvred irrespective of the wind conditions.[34]

In 1840 in London, Trinity House drew up a set of regulations which were enacted by Parliament in 1846. The Trinity House rules were included in the Steam Navigation Act 1846, and the Admiralty regulations regarding lights for steam ships were included in this statute in 1848.[32] In 1849 Congress extended the light requirements to sailing vessels on US waters. In the UK in 1858 coloured sidelights were recommended for sailing vessels and fog signals were required to be given, by steam vessels on the ship's whistle and by sailing vessels on the fog horn or bell, while a separate but similar action was also taken in the United States as by 1850 onwards, English maritime law on collisions was being gradually adopted in United States law.[35][a] Also in 1850, courts in the England and the United States adopted common law pertaining to reasonable speed within the Assured Clear Distance Ahead.[36][b][37][c][38][d]

In 1863 a new set of rules drawn up by the British Board of Trade, in consultation with the French government, came into force. By 1864 the regulations (or Articles) had been adopted by more than thirty maritime countries, including Germany and the United States (passed by the United States Congress as Rules to prevent Collisions at Sea. An act fixing certain rules and regulations for preventing collisions on the water. 29 April 1864, ch. 69.[39] and signed into law by President Abraham Lincoln). International regulations would continue to be further developed over the next several decades as a result of legislative and government action by the UK, US and other maritime States. For example, in 1867, Thomas Gray, assistant secretary to the Maritime Department of the Board of Trade, wrote The Rule of the Road, a pamphlet that became famous for its well-known mnemonic verses.[40] Furthermore, in 1878, the United States codified its common law rules for reducing the risk of collisions.[41][e] By 1880, the 1863 international Articles were supplemented with whistle signals and in 1884 a new set of international regulations was implemented.

In 1889, the United States convened the first international maritime conference in Washington, D.C to further codify international collision regulations, including requirements for lights and shapes.[32] The resulting rules were adopted in 1890 and effected in 1897. Some minor changes were made during the 1910 Brussels Maritime Conference and some rule changes were proposed, but never ratified, at the 1929 International Conference on Safety of Life at Sea (S.O.L.A.S.) With the recommendation that the direction of a turn be referenced by the rudder instead of the helm or tiller being informally agreed by all maritime nations in 1935.

The 1948 S.O.L.A.S. International Conference made several recommendations, including the recognition of radar; these were eventually ratified in 1952 and became effective in 1954. Further recommendations were made by a SOLAS Conference in London in 1960 which became effective in 1965.[42]

The 1972 International Regulations for Preventing Collisions at Sea

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The International Maritime Organization Headquarters building, where amendments to the regulations are discussed and adopted

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.[1] As of June 2013, the convention has been ratified by 155 states representing 98.7% of the tonnage of the world's merchant fleets.[43]

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 Traffic Separation Schemes (TSS).[44] 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.[1]

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.

Jurisdictions

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The International Maritime Organization (IMO) convention, including the almost four dozen "rules" contained in the international regulations, must be adopted by each member country that is signatory to the convention—COLREG laws must exist within each jurisdiction.[45] Thereafter, each IMO member country must designate an "administration"—national authority or agency—for implementing the provisions of the COLREG convention, as it applies to vessels over which the national authority has jurisdiction.[46] Individual governing bodies must pass legislation to establish or assign such authority, as well as to create national navigation laws (and subsequent specific regulations) which conform to the international convention; each national administration is thereafter responsible for the implementation and enforcement of the regulations as it applies to ships and vessels under its legal authority.[47] As well, administrations are typically empowered to enact modifications that apply to vessels in waters under the national jurisdiction concerned, provided that any such modifications are not inconsistent with the COLREGs.[48]

Canada

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The Canadian version of the COLREGs is provided by Transport Canada, which regulates Canadian vessels.[49][50]

Korea

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South Korea ratified the COLREGs in 1977 and enacted enforcing legislation under the 1986 Korea Marine Traffic Safety Act.[51]

Marshall Islands

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For Marshall Islands waters and ships, Chapter 22.11.4 requires all vessels to comply with the 1972 COLREGs, as amended.[52] Section 150 of the Maritime Act encompasses the fitting and provision of navigation lights, shapes and sound signalling equipment.[52]

Singapore

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The version of the COLREGs applicable to the territorial waters of Singapore is the Merchant Shipping (Prevention of Collisions at Sea) Regulations.[53] These Rules were enacted by Singapore in 1983 and then revised and reissued 25 March 1992.[53]

United Kingdom

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The UK version of the COLREGs is provided by the Maritime and Coastguard Agency (MCA), in the Merchant Shipping (Distress Signals and Prevention of Collisions) Regulations of 1996.[54] They are distributed and accessed in the form of a "Merchant Shipping Notice" (MSN), which is used to convey mandatory information that must be complied with under UK legislation. These MSNs relate to Statutory Instruments and contain the technical detail of such regulations.[55] Material published by the MCA is subject to Crown copyright protection, but the MCA allows it to be reproduced free of charge in any format or medium for research or private study, provided it is reproduced accurately and not used in a misleading context.[56]

United States

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The US version of the COLREGs is provided by the United States Coast Guard of the US Department of Homeland Security.[57]

No right-of-way

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A commonly held misconception concerning the rules of marine navigation is that by following specific rules, a vessel can gain certain rights of way over other vessels.[58] No vessel ever has "right of way" over other vessels. Rather, there can be a "give way" vessel and a "stand on" vessel, or there may be two give way vessels with no stand on vessel. A stand on vessel does not have any right of way over any give way vessel, and is not free to maneuver however it wishes, but is obliged to keep a constant course and speed (so as to help the give way vessel in determining a safe course). So standing on is an obligation, not a right, and is not a privilege. Furthermore, a stand on vessel may still be obliged (under Rule 2 and Rule 17) to give way itself, in particular when a situation has arisen where a collision can no longer be avoided by actions of the give way vessel alone.[59][60] For example, two power-driven vessels approaching each other head-to-head, are both deemed to be "give way" and both are required to alter course so as to avoid colliding with the other. Neither vessel has "right of way".[61]

Future

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In recent years, the IMO, States and other interested parties have assessed the COLREGs with a view to potential future amendment to facilitate Maritime Autonomous Surface Ships.[62][63][64] These include a regulatory scoping exercise to review the applicability of the COLREGs for autonomous ships.[65]

Racing Rules

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The Racing Rules of Sailing, which govern the conduct of yacht and dinghy racing under the sanction of national sailing authorities which are members of World Sailing, are based on the COLREGs, but differ in some important matters such as overtaking and right of way close to turning marks in competitive sailing.[66]

See also

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English Wikisource has original text related to this article:

References

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Notes

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Further reading

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Revisions and contributorsEdit on WikipediaRead on Wikipedia

International Regulations for Preventing Collisions at Sea

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The International Regulations for Preventing Collisions at Sea, 1972 (COLREGS) constitute a comprehensive set of maritime rules adopted as a multilateral convention by the (IMO) on 20 October 1972, entering into force on 15 July 1977, to standardize navigation practices and avert collisions among vessels on the high seas and in connected navigable waters. These regulations apply universally to all vessels upon the high seas, including power-driven, , , and seaplanes, as well as non-displacement craft like air-cushion vehicles, with limited exemptions for warships, naval auxiliaries, and certain traditional vessels. Structurally, the COLREGS comprise 41 rules divided into six parts and supplemented by four annexes that outline technical details such as positioning of lights and shapes, and sound signaling appliances. Part A establishes general principles, including the responsibility to avoid collisions and the use of all available means for detection. Part B details and rules across three sections: application (Section I, Rules 4–10), conduct in sight of one another (Section II, Rules 11–18), and conduct in restricted visibility (Section III, Rule 19). Parts C and D specify requirements for lights, shapes, and sound/light signals to indicate vessel status and intentions, while Part E provides for exemptions and Part F addresses verification of compliance through inspections and certifications. Historically, the 1972 COLREGS superseded the 1960 International Regulations for Preventing Collisions at Sea, incorporating innovations like mandatory traffic separation schemes—first trialed in the Dover Strait in 1967 and formalized in 1971—which demonstrably reduced collisions in high-traffic areas, for instance, from around 60 incidents in 1956–1960 to 16 by in that strait. Administered by the IMO, the regulations have been amended several times to adapt to evolving technologies and practices, with notable updates in (effective ), (effective ), and (effective ), further amendments in 2001 (effective 2003), 2007 (effective 2009), and 2014 (effective 2016), ensuring ongoing relevance in global shipping safety. As of November 2025, the convention has been ratified by 166 contracting states, representing approximately 98.91% of the world's .

Introduction

Purpose and Scope

The International Regulations for Preventing Collisions at Sea (COLREGS) establish uniform rules to prevent collisions by defining predictable actions and responsibilities for vessels in diverse navigational scenarios, such as crossing paths, , or operating in congested areas. These regulations prioritize collision avoidance over strict adherence to right-of-way privileges, requiring every vessel to take positive action when a risk of collision arises, regardless of its designated role. The scope of the COLREGS extends to all vessels navigating the high seas and all connected navigable waters, encompassing powered vessels, sailing vessels, fishing vessels, and non-displacement craft like or wing-in-ground-effect (WIG) craft. This broad applicability ensures consistent safety standards across , though it allows for special rules in harbors, rivers, or inland waterways that align closely with the core principles, as well as limited exemptions for vessels of war, those under , or ships of special construction where alternative signals are authorized by governments to avoid confusion. Certain pre-existing vessels, such as those built before the convention's , may operate under transitional conditions. Key principles underlying the COLREGS emphasize proactive prevention, including maintaining a continuous lookout, proceeding at safe speeds, and adapting maneuvers to conditions like restricted or limited maneuverability, thereby promoting safe navigation for all vessel types. These evolved from the post-World War II surge in global shipping traffic and radar-equipped vessels, which heightened collision risks and necessitated international standardization. The COLREGS complement other (IMO) conventions, such as the International Convention for the Safety of Life at Sea (SOLAS), by focusing specifically on collision prevention within the broader maritime safety framework. The International Regulations for Preventing Collisions at Sea, 1972 (COLREGS), were adopted by the (IMO) on October 20, 1972, as a formally titled the Convention on the International Regulations for Preventing Collisions at Sea. The convention entered into force on July 15, 1977, following by states representing at least 65% of the world's of vessels over 100 gross tons, as required by Article IV. As of November 2025, COLREGS has been ratified or acceded to by 166 contracting states, encompassing approximately 98.7% of global merchant shipping tonnage, making it one of the most universally adopted maritime treaties. The regulations are legally binding on all vessels registered in contracting states, which must incorporate the rules into their national legislation to ensure uniform application. For instance, many states, such as the through the , have enacted domestic laws mirroring COLREGS to enforce compliance on their flagged vessels. Non-contracting states, though not formally bound, frequently adopt equivalent rules voluntarily to align with international standards and facilitate safe navigation in shared waters. This widespread adoption underscores the treaty's role in promoting global maritime safety without direct extraterritorial enforcement mechanisms. COLREGS applies to all vessels navigating the high seas and connected waters navigable by seagoing vessels, excluding such as harbors, rivers, and lakes where local rules may prevail, provided those local provisions conform as closely as possible to the international standards. The rules primarily target vessels over 7 meters in length, with specific provisions for lights and signals scaled accordingly, though core principles of collision avoidance extend to smaller craft. Seaplanes are included as vessels when operating on the but follow adapted display requirements; submerged must adhere to and rules to avoid collisions but are exempt from surface light and shape displays under operational protocols. These applicability boundaries ensure broad coverage while accommodating practical limitations. Enforcement of COLREGS falls primarily under the responsibility of the , which must survey and certify its vessels' compliance through inspections and flag state control measures. Port states supplement this by conducting inspections on foreign vessels to verify adherence to the regulations, with authority to detain non-compliant ships until deficiencies are rectified. This dual framework, supported by IMO guidelines, enhances accountability across jurisdictions. The regulations also intersect briefly with the United Nations Convention on the Law of the Sea (UNCLOS) by operationalizing safe navigation freedoms on the high seas.

Historical Development

Early Collision Prevention Rules

The advent of steam-powered navigation in the early 19th century highlighted the dangers of collisions at sea, prompting initial national efforts to establish preventive rules. In 1840, the Corporation of Trinity House in the United Kingdom drafted regulations for steam vessels, emphasizing port-to-port passing in narrow channels and altering course to starboard to avoid crossing paths. These were formalized in the Steam Navigation Act of 1846, marking the first statutory framework for collision avoidance in British waters. Complementing these, the British Admiralty's 1848 regulations introduced standardized navigation lights, including red and green sidelights for port and starboard, along with a white masthead light, to improve visibility during nighttime or restricted conditions. Across the Atlantic, the enacted its own rules in 1864 through an signed by President , which adopted similar principles such as keeping to the starboard side and requiring clear visibility of sidelights. By the end of that year, these provisions—often referred to as the "Articles"—had been embraced by over 30 maritime nations, including , fostering a degree of informal international alignment. further refined its guidelines in subsequent years, mandating fog signals for sailing vessels by 1858 and whistle signals for maneuvers by 1880, though enforcement remained inconsistent due to varying national interpretations. Efforts toward global uniformity gained momentum with the 1889 International Marine Conference in Washington, D.C., convened by the and attended by representatives from more than 30 nations. The resulting regulations, effective from 1897 in key maritime powers like the and , introduced concepts such as the "stand-on" vessel maintaining course and speed while the "giving-way" vessel takes early evasive action, along with a second masthead light for larger steamships. The 1910 Brussels Convention for the Unification of Certain Rules of Law with Respect to Collisions between Vessels shifted focus to post-collision liability, apportioning damages based on degrees of fault rather than prevention, and requiring mutual assistance between vessels involved. In the interwar period, the League of Nations convened the 1929 International Convention for the Safety of Life at Sea (SOLAS), which annexed revised collision rules emphasizing direct helm commands (e.g., "starboard" for rudder to starboard) and minor updates to visibility and signaling protocols; these entered force in 1933 but saw limited ratification. Broader League initiatives to harmonize maritime safety stalled amid rising geopolitical tensions leading to . The resulting patchwork of national and partial international rules created persistent inconsistencies, such as divergent interpretations of and crossing scenarios, which undermined effective prevention and prompted the postwar establishment of the Intergovernmental Maritime Consultative Organization (now the ) in 1948 to pursue comprehensive standardization. These foundational efforts directly influenced the of the 1972 COLREGS.

Adoption of the 1972 COLREGS

The negotiation process for the 1972 Convention on the International Regulations for Preventing Collisions at Sea (COLREGS) spanned several sessions of the (IMO) from 1967 to 1972, involving representatives from more than 50 nations. These discussions addressed significant gaps in the 1960 International Regulations for Preventing Collisions at Sea, which had been adopted alongside the 1960 Safety of Life at Sea ( but lacked comprehensive provisions for emerging technologies like and structured approaches to vessel traffic management, such as traffic separation schemes. The process culminated in an international conference convened by the IMO in , where the regulations were finalized and adopted on October 20, 1972, marking a key milestone in establishing a unified global standard for maritime collision prevention. The convention entered into force 12 months after the date on which at least 15 states, whose combined merchant fleets constituted not less than 65 per cent of the of the world's merchant shipping (of vessels of 100 gross tons and over), had become parties to it. This threshold was met, leading to the COLREGS taking effect on July 15, 1977, thereby replacing the 1960 regulations. Among the innovations introduced in the 1972 COLREGS were a restructured format dividing the rules into five parts and four annexes for enhanced clarity and usability; explicit definitions of responsibilities for "give-way" vessels (required to take early and substantial action to avoid collision) and "stand-on" vessels (required to maintain course and speed but permitted to act if necessary); and the formal integration of separation schemes as mandatory under Rule 10, building on voluntary schemes first implemented in areas like the Dover Strait in 1967 and endorsed by the IMO Assembly in 1971. Initial challenges during adoption included resistance from some nations to extending the rules' applicability to inland waters, preferring separate domestic regulations, while the strongly advocated for a unified set of rules harmonizing international and to simplify compliance for its extensive inland waterways.

Amendments and Revisions

The process for amending the International Regulations for Preventing Collisions at Sea (COLREGS) is governed by Article XI of the 1972 Convention, under which proposals are submitted by Contracting Parties to the (IMO) Maritime Safety Committee for consideration and recommendation to the IMO Assembly for adoption, either explicitly or through a tacit acceptance procedure requiring no objections within a specified period. The first major set of amendments was adopted by IMO Assembly Resolution A.464(XII) on 19 November 1981, primarily clarifying the application of the regulations under Rule 1, including provisions for vessels of special construction and exemptions for certain operations, and entered into force on 1 June 1983. Subsequent amendments in 1987, adopted by IMO Resolution A.626(15), refined Rule 10 on traffic separation schemes to emphasize their applicability only to IMO-adopted schemes and clarified crossing procedures, entering into force on 19 November 1989. Amendments adopted in 1989 by IMO Resolution A.678(16) further clarified provisions in Rule 10 regarding vessels using the inshore traffic zone, entering into force on 19 April 1991. Further updates in 1993, adopted by IMO Resolution A.736(18) on 4 November 1993, addressed refinements to traffic separation schemes under Rule 10 and entered into force on 4 November 1995. The 2001 amendments, adopted by IMO Assembly Resolution A.910(22) on 29 November 2001, introduced provisions for wing-in-ground (WIG) craft in Rule 3 and related definitions, along with adjustments for vessels engaged in operations treated as restricted in ability to maneuver under Rule 3(g), entering into force on 29 November 2003. Amendments adopted in 2007 by IMO Assembly Resolution A.1004(25) on 29 November 2007 focused on sound and light signals, including revisions to Rules 33 and 35 for equipment on small vessels and Annex III for technical details of sound signal appliances, entering into force on 1 December 2009. These changes incorporated considerations for emerging technologies like (AIS) in conjunction with traditional signals, though AIS integration remains guided by broader IMO safety standards rather than direct COLREGS revisions. As of 2025, no major amendments have been adopted since the 2013 revisions by IMO Assembly Resolution A.1085(28), adopted on 4 December 2013, which added Part F (Rules 39–41) for compulsory audits of Contracting Parties' compliance but included minor clarifications on light positioning in Annex I, entering into force on 1 January 2016; the IMO continues to review potential updates for unmanned vessels through its Maritime Safety Committee, but none have been formally adopted. Since 1972, the COLREGS have undergone a total of seven formal amendment cycles to address technological and operational evolutions.

Structure of the Regulations

Part A: General Provisions

Part A of the International Regulations for Preventing Collisions at Sea (COLREGS), adopted in 1972 under the auspices of the (IMO), establishes the foundational framework for the entire set of rules, defining their scope, responsibilities, and key terminology to ensure uniform application across . These provisions apply universally to promote safe navigation and prevent collisions by setting baseline obligations that subsequent parts build upon. Rule 1 delineates the application of the COLREGS, stating that they govern all vessels upon the high seas and in all connected navigable waters accessible to seagoing vessels. This includes territorial seas, but the rules do not supersede special local regulations established by appropriate authorities for areas such as roadsteads, harbors, rivers, lakes, or inland waterways, provided those local rules align as closely as possible with the COLREGS. Exemptions are also carved out for vessels, convoys, and fishing fleets, allowing governments to prescribe additional signal lights or whistles that remain distinguishable from standard ones authorized under the regulations. Furthermore, the IMO may adopt traffic separation schemes to enhance orderly vessel movement, and vessels of unique construction or purpose—such as ships or icebreakers—may receive government-approved alternatives for lights, shapes, and signals that achieve the closest practical compliance without compromising their specialized functions. These provisions ensure broad applicability while accommodating operational necessities and local variations, reinforcing the COLREGS' role as a baseline international standard tied to their legal status as a binding convention for ratifying states. Rule 2 addresses responsibility, emphasizing that no vessel, owner, master, or is absolved from liability for failing to adhere to the COLREGS or for omitting precautions dictated by standard practices or case-specific conditions. This underscores a of absolute accountability, where neglect of the rules or undue risks cannot be excused, promoting a culture of in . However, the rule allows flexibility by requiring interpreters and operators to consider all navigational hazards and collision risks, as well as special circumstances like vessel limitations, permitting deviations from the rules if necessary to avert immediate danger. In essence, this balances strict compliance with practical judgment, ensuring safety remains paramount without rigid adherence that could exacerbate threats. Rule 3 provides general definitions to clarify terms used throughout the COLREGS, preventing ambiguity in their interpretation and application. Central to these is the broad definition of a vessel, encompassing every type of —including non-displacement craft like and seaplanes—capable of waterborne transport. It distinguishes power-driven vessels as those propelled by machinery, as those under (with machinery disengaged if present), and vessels engaged in fishing as those using gear like nets or trawls that impair maneuverability, excluding less restrictive methods such as trolling. Specialized categories include vessels not under command, which face exceptional circumstances preventing compliance with maneuvering requirements; vessels restricted in their ability to maneuver, such as those laying marks, , or in ways that limit deviation; and vessels constrained by their draught, power-driven ships whose deep draft relative to water depth severely restricts course changes. Other key terms cover operational states, like a vessel being when not anchored, aground, or secured to shore; physical measurements, where and breadth refer to overall dimensions; visibility contexts, with vessels in sight only if visually observable to each other; and environmental conditions, defining restricted visibility as any reduction due to , , , , sandstorms, or similar factors. These definitions, amended in 2001 (effective 29 July 2003) to include wing-in-ground (WIG) craft, provide a precise that supports consistent enforcement and operational decision-making. Collectively, Part A's provisions lay a prudent regulatory foundation, insisting on compliance while encouraging vigilant adaptation to real-world maritime challenges, thereby mitigating collision risks through clear scope, , and standardized .

Part B: Steering and Sailing Rules

Part B of the International Regulations for Preventing Collisions at Sea (COLREGS), known as the and Rules, encompasses Rules 4 through 19 and establishes the primary obligations for vessels to navigate safely and avoid collisions regardless of vessel type or operational status. These rules are structured into three sections differentiated by conditions, prioritizing proactive measures, clear responsibilities between vessels, and the overriding to take action when necessary to prevent danger. Adopted under the 1972 Convention, they apply to all vessels upon the high seas and in waters connected therewith navigable by seagoing vessels, promoting uniform conduct to reduce maritime accidents.

Section I: Application in Any Visibility (Rules 4–10)

Section I outlines fundamental conduct applicable in all visibility conditions, ensuring vessels maintain vigilance and assess situations systematically to mitigate collision risks from the outset. Rule 4 specifies that these provisions govern all vessels in any visibility, forming the baseline for subsequent actions. A core requirement under Rule 5 is the maintenance of a proper look-out at all times using sight, hearing, and all available means appropriate to the circumstances, enabling a full appraisal of the situation and potential collision hazards. This includes and other detection equipment when fitted, underscoring the need for constant awareness to detect other vessels, obstacles, or environmental factors early. Rule 6 mandates proceeding at a safe speed, defined as one allowing proper and effective action to avoid collision and stop within a suitable to prevailing conditions, such as , , vessel maneuverability, and background light. Factors like the state of the vessel's engines, presence of navigational hazards, and must be considered; for instance, in congested areas, speeds should permit timely alterations without relying solely on stopping power. Assessing of collision is addressed in Rule 7, requiring the use of all available means, including plotting or systematic observations if equipped, to determine if exists; doubt must be resolved by assuming is present. Key indicators include a constant bearing of an approaching vessel, signaling a steady closing course, though may also arise even with changing bearings, particularly near large vessels or tows . Assumptions based on limited data, especially sparse plots, are prohibited to prevent misjudgments. Rule 8 emphasizes that any action to avoid collision must be positive, timely, and substantial, with alterations in course or speed large enough to be apparent to others visually or by , avoiding successive small changes. If sea room allows, course alteration alone may suffice if made early and decisively, but all maneuvers must ensure a passing , with effectiveness monitored until clear. Vessels may slacken speed, stop, or reverse if needed to assess or avert danger, and those required not to impede others must provide ample sea room proactively. In constrained areas, Rule 9 requires vessels in narrow channels or fairways to keep as near as safe and practicable to the starboard outer limit, with smaller vessels, vessels, or those not impeding larger ones restricted to the channel. Crossing such areas is prohibited if it impedes passage, and signals must be used when necessary, while vessels approaching bends must navigate cautiously and sound appropriate signals. Anchoring in narrow channels should be avoided when possible. Rule 10 governs traffic separation schemes, directing vessels to proceed in the appropriate lane's general flow direction, joining or leaving at small angles, and crossing lanes at near right angles when unavoidable. Separation zones and lines should be avoided, and non-participating vessels must keep clear; fishing or small vessels must not impede those in lanes, with exceptions for emergencies or operations.

Section II: Conduct in Sight of One Another (Rules 11–18)

Section II applies specifically when vessels are in visual sight of each other (Rule 11), detailing maneuvers for common encounter scenarios and assigning give-way and stand-on roles to clarify responsibilities and prevent confusion during close-quarters . These rules build on Section I by specifying vessel interactions visible to the . For vessels under Rule 12, when risk of collision exists in a crossing situation, the vessel with the wind on its port side keeps clear of the one with wind on the starboard side; if both have wind on the same side, the windward vessel yields to the leeward one. Same-wind situations on opposite tacks follow the port-yielding-to-starboard principle, ensuring predictable avoidance based on wind direction observable visually. Rule 13 defines : any vessel approaching another from more than 22.5 degrees abaft the beam must keep clear, regardless of vessel type, with the overtaken vessel maintaining course and speed. This applies until well clear, promoting the overtaker's sole responsibility to maneuver safely astern. In head-on situations between power-driven vessels (Rule 14), both must alter course to starboard to pass port-to-port, assuming mutual compliance unless otherwise apparent. For crossing situations (Rule 15), the vessel that sees the other on its starboard side acts as give-way and keeps clear, establishing a simple starboard privilege to resolve ambiguities when courses intersect at less than 90 degrees. The give-way vessel under Rule 16 must take early and substantial action to avoid the stand-on vessel, such as altering course or speed decisively, ensuring the stand-on vessel can maintain its path without deviation. Rule 17 outlines stand-on vessel duties: it maintains course and speed but must take action to avoid collision if the give-way vessel fails to do so or if risk becomes imminent, particularly in close quarters. This reinforces that no vessel is absolved from the ultimate responsibility to avert danger, even if designated stand-on. For example, a stand-on vessel may slacken speed or alter course substantially if the give-way shows no intent to maneuver. Rule 18 establishes a of responsibilities: power-driven vessels give way to vessels not under command, restricted in ability to maneuver, engaged in , or ; vessels engaged in yield to those not under command or restricted in maneuverability. This prioritization protects more vulnerable or constrained vessels, with all types required to avoid impeding privileged ones while still complying with other rules. A vessel restricted in its ability to maneuver, such as one or laying cables, holds priority over most others due to its limited options, though every vessel retains the duty to act if collision looms.

Section III: Conduct in Restricted Visibility (Rule 19)

Section III addresses navigation solely in or near restricted visibility (Rule 19), where visual cues are limited, requiring vessels to proceed at a safe (often minimal) speed, post extra look-outs, and use or equivalent aids to detect others promptly. If a close-quarters situation develops, speed must be reduced to the minimum or stopped to assess actions, with course alterations preferably to starboard but avoiding port turns when unsure of the other's position or course to prevent compounding risks. Sound signals must be made as prescribed, and vessels detected ahead, abeam, or crossing from the side prompt immediate substantial action to avoid them; those crossing from starboard or require keeping clear. This section ensures cautious, -informed decision-making in , , or , overriding visual rules from Section II. Throughout Part B, the prioritizes vessels restricted in maneuverability—such as those constrained by draft, , or operations—over others, including power-driven vessels, to account for their reduced evasion capabilities, while emphasizing that no rule excuses collision; all must deviate if needed. The key principle in Rule 17—that stand-on vessels act if give-way vessels falter—embeds flexibility, ensuring safety trumps rigid adherence and allowing intervention when default maneuvers fail.

Part C: Lights and Shapes

Part C of the International Regulations for Preventing Collisions at Sea (COLREGS) outlines the requirements for visual signals through lights and shapes, enabling vessels to identify each other's type, status, activity, and course from a distance to avoid collisions. These rules, spanning Rules 20 to 31, emphasize standardized displays that convey critical navigation information, particularly when vessels are in sight of one another, complementing the steering and sailing rules in Part B. The provisions ensure that lights are used at night or in restricted visibility, while shapes serve daytime identification, promoting mutual awareness in congested or open waters. Compliance is mandatory in all weather conditions, with lights and shapes adhering to technical specifications in Annex I, including color, intensity, and positioning to maintain visibility without confusion. Rule 20 mandates the application of these signals universally, requiring lights from sunset to sunrise unless they could be mistaken for navigation aids or impair , and shapes exclusively by day. Lights may also be shown in daylight during restricted or when necessary for safety. This framework prioritizes clear, unambiguous signaling to allow early detection, typically at ranges determined by vessel size and light intensity as detailed in Rule 22 and Annex I Section 8. For instance, on vessels over 50 meters, a masthead light must be visible for at least 6 nautical miles, sidelights for 3 nautical miles, and all-round lights for 3 nautical miles, ensuring reliable recognition up to several miles away. Central to Part C are the definitions in Rule 21, which standardize key lights for consistent interpretation. A masthead light is a white forward-facing light spanning 225 degrees of the horizon (from right ahead to 22.5 degrees abaft each beam), indicating the vessel's heading. Sidelights consist of a light on the side and on starboard, each covering 112.5 degrees (right ahead to 22.5 degrees abaft the beam), revealing the vessel's broadside direction. The sternlight, a white aft light over 135 degrees (67.5 degrees from right astern on each side), marks the rear. Additional types include the towing light (yellow, identical to the sternlight), all-round light (360 degrees unbroken), and flashing light (at least 120 flashes per minute for specific uses). These arcs and colors, specified in Annex I, prevent overlap or ambiguity, with sidelights combinable in one fixture for vessels under 20 meters. For power-driven vessels , Rule 23 requires a forward masthead , a second masthead abaft and higher (optional under 50 meters), sidelights, and a sternlight to clearly signal propulsion and direction. Smaller vessels under 12 meters may substitute with an all-round white and sidelights, or just an all-round white if under 7 meters and not exceeding 7 knots. Special categories include air-cushion vessels in non-displacement mode, which add an all-round flashing yellow , and wing-in-ground () craft during takeoff, landing, or low flight, which add a high-intensity all-round flashing red . These configurations allow observers to discern a power-driven vessel's size, speed potential, and operational mode from afar. Towing and pushing operations under Rule 24 demand enhanced visibility to highlight the extended length and configuration. A power-driven vessel displays two masthead lights in a vertical line (three if the tow exceeds 200 meters from to tow's end), sidelights, a sternlight, and a above the sternlight, with a by day for tows over 200 meters. Pushed vessels not rigidly connected as a composite unit (treated as a single power-driven vessel under Rule 23) show two masthead lights, sidelights, and a sternlight. Towed vessels exhibit sidelights and a sternlight, plus a if over 200 meters; inconspicuous or submerged tows use multiple all-round white lights spaced no more than 100 meters apart for lengths over 100 meters, plus diamonds at ends. If full lighting is impracticable, alternative measures must indicate presence, ensuring the entire tow string is visible to approaching traffic. Sailing vessels and those under oars, per Rule 25, require simpler displays without power-driven lights: sidelights and a sternlight, combinable in one near the mast top for vessels under 12 meters. An optional tricolor ( over all-round lights vertically) may supplement but not replace the lantern. Vessels under 7 meters or under oars must, if practicable, show these lights or have a white-light ready for immediate exhibition to avert collision. A conical (apex down) indicates when a vessel is also using auxiliary machinery. This minimal setup reflects their reliance on or manual power, prioritizing directional cues over propulsion status. Fishing vessels, addressed in Rule 26, display unique signals to denote their activity and gear deployment, which may restrict maneuverability. vessels show two all-round lights vertically (green over white) or two cones apex-to-apex (or a for under 20 meters), plus a masthead light abaft the green (optional under 50 meters), and sidelights/sternlight when making way. Non-trawling uses red over white all-round lights or a ball over diamond shape. For gear extending more than 150 meters perpendicular to the vessel, all-round white lights mark the outer edges, with flashing yellow lights (if gear obstructs >50% of the horizon) or additional signals for direction and presence. These prevent entanglements by alerting others to the vessel's engaged status and zone. Vessels not under command or restricted in ability to maneuver (Rule 27) use red and white all-round lights in vertical lines—two reds for not under command (with two black balls by day), or red-white-red for restricted maneuverability (with ball-diamond-ball shapes)—positioned to show in all directions. Underwater operations or dredging add lights and a diamond to indicate safe or obstructed sides. Such displays signal limited control, prompting others to keep clear. Rule 28 specifies vessels constrained by draft (international waters only) with three red all-round lights or a cylinder shape, highlighting their channel restriction. Pilot vessels (Rule 29) exhibit white over red all-round lights when engaged, plus standard underway lights, and may use an identifying signal. Anchored or aground vessels under display one or more all-round white s (forward and aft for over 50 ) or a single central for smaller ones, with a black ball shape by day; aground vessels add two vertical red s or balls. Seaplanes and craft (Rule 31) approximate these displays as closely as their structure allows, adapting positions per Annex I. Overall, these rules in Part C, supported by Annex I's technical standards for heights (e.g., masthead at least 6 above hull for vessels over 20 ) and intensities, ensure shapes like balls (anchored/not under command) and diamonds (towing/restricted) provide daytime equivalents to s, fostering safe, predictable interactions at sea.
Vessel TypeKey Lights (Night)Key Shapes (Day)Purpose
Power-driven ()Masthead (1-2 ), sidelights (/), sternlight ()None requiredIndicate and heading
Towing (>200m tow)2-3 masthead , sidelights, sternlight, yellow towing lightHighlight extended length and tow status
()Sidelights, sternlight (combinable) (apex down if motorized)Show non-power direction
()Green over all-round; masthead, sidelights/sternlight if making wayTwo cones apex-to-apexDenote gear activity and restrictions
Not under commandTwo all-round (vertical)Two s (vertical)Signal inability to maneuver
AnchoredAll-round (1-2) Mark stationary position
AgroundAll-round + two vertical + two vertical sIndicate and
This table illustrates representative configurations; full details vary by size and conditions per Rules 23-31 and Annex I.

Part D: Sound and Light Signals

Part D of the International Regulations for Preventing Collisions at Sea (COLREGS) outlines the use of sound signals and supplementary light signals to communicate vessel intentions, status, and warnings, particularly in conditions of restricted visibility where visual signals from Part C may be insufficient. These rules ensure clear auditory cues for safe navigation, emphasizing standardized blasts from whistles, bells, and gongs to prevent misunderstandings among vessels. The provisions integrate with light signals by allowing optional flashing white lights to accompany certain sound maneuvers, enhancing visibility when vessels are in sight of one another. Rule 32 provides key definitions for sound signals used throughout Part D. A "" refers to a sound-signaling appliance meeting the technical specifications in Annex III, while a "short blast" lasts approximately one second, and a "prolonged blast" endures 4 to 6 seconds. These definitions standardize signal durations to promote uniformity in maritime communication. Rule 33 specifies equipment requirements based on vessel length to ensure effective sound production. Vessels of 12 meters or more in length must carry a and a bell, with those 100 meters or more also requiring a whose note is distinct from the bell. Vessels under 12 meters are exempt from these requirements but must have some means of making an efficient signal. Annex III details the standards for these appliances, including frequencies between 70 and 700 Hz and minimum levels—for instance, at least 143 dB at 1 meter for vessels over 200 meters to achieve an audible range of 2 nautical miles, scaling down to 120 dB and 0.5 nautical miles for vessels under 20 meters. Bells and must produce at least 110 dB at 1 meter, with bell mouth diameters of at least 300 mm for vessels over 20 meters and 200 mm for those between 12 and 20 meters, ensuring corrosion-resistant construction for clear, distinct tones. Rule 34 addresses maneuvering and warning signals for vessels in sight of one another. When altering course, a single short blast indicates a turn to starboard, two short blasts signal a turn to , and three short blasts denote operating astern propulsion. In narrow channels during , the overtaking vessel sounds two prolonged blasts followed by one short blast for starboard-side passing or two short blasts for port-side, with the overtaken vessel acknowledging via one prolonged, one short, one prolonged, and one short blast upon agreement. For situations of doubt or as a warning, at least five short rapid blasts are used, which may be supplemented by corresponding flashing white lights visible for at least 5 miles. Approaching a bend or obstruction prompts one prolonged blast, mirrored by the other vessel. Rule 35 prescribes sound signals in restricted visibility, such as fog or mist, to indicate vessel status at intervals not exceeding two minutes unless otherwise specified. A power-driven vessel making way through the water sounds one prolonged blast, while one stopped and making no way emits two prolonged blasts separated by about two seconds. Vessels not under command, restricted in ability to maneuver, sailing, or engaged in fishing or towing sound one prolonged followed by two short blasts; a manned vessel being towed adds one prolonged and three short blasts, with unmanned towed vessels ringing a bell rapidly for about five seconds at similar intervals. Vessels at anchor ring the bell rapidly for about five seconds every minute, with those 100 meters or longer adding a gong aft; an optional warning of one short, one prolonged, and one short blast may precede this. Aground vessels perform the anchor signal plus three distinct bell strokes before and after each sequence, potentially augmented by the whistle. Pilot vessels may supplement their signals with four short blasts to identify themselves. Smaller vessels under 12 meters must make efficient sounds at two-minute intervals but are not required to use bells or gongs. Rule 36 permits signals to attract attention using any light or sound not resembling those defined elsewhere in the regulations, such as directing a toward a without dazzling other vessels or using high-intensity intermittent lights that could be confused with distress signals. This flexibility supports while maintaining signal integrity. Rule 37 mandates the use of distress signals as detailed in Annex IV, such as the international signal for distress (e.g., via radio or continuous sounding of the fog signal) when a vessel requires assistance, ensuring rapid recognition in emergencies. These signals complement the operational sounds in Part D by prioritizing life-saving communications.

Part E: Exemptions

Part E (Rule 38) provides limited exemptions from the COLREGS for vessels constructed before the convention's entry into force on 15 July 1977, allowing them to retain pre-existing installations for lights, shapes, and sound signals if they meet equivalent safety standards. Any changes to such vessels must conform to the regulations. This part ensures a transitional approach without compromising overall safety. Warships and certain government vessels may also receive exemptions under specific conditions.

Part F: Verification of Compliance

Part F, added by amendments adopted on 4 December 2013 (Resolution A.1085(28)) and entering into force on 1 January 2016, comprises Rules 39–41 and establishes mechanisms for verifying compliance with the COLREGS. Rule 39 outlines general obligations for Contracting Parties to maintain effective systems for surveys, inspections, and certifications. Rule 40 details requirements, including issuance of certificates and authorization of recognized organizations. Rule 41 addresses , empowering inspections and detention for non-compliance. This part enhances global enforcement through mandatory audits and reporting to the IMO.

Annexes I–IV

The annexes to the International Regulations for Preventing Collisions at Sea (COLREGS) provide essential technical specifications for lights, shapes, sound signals, and distress indicators, ensuring standardized equipment across vessels to facilitate uniform application of the core rules globally. These annexes promote by detailing positioning, intensities, and construction requirements, allowing mariners to reliably interpret signals from distant or approaching vessels. Annex I outlines the positioning and technical details of lights and shapes to guarantee clear visibility and non-interference. Vertical positioning requires the forward masthead light on power-driven vessels of 20 meters or more in length to be at least 6 meters above the hull, with the after masthead light at least 4.5 meters higher than the forward one; for vessels between 12 and 20 meters, the masthead light must be at least 2.5 meters above the , while smaller vessels under 12 meters may have the uppermost less than 2.5 meters above the but at least 1 meter above sidelights if combined. Horizontal placement mandates that masthead lights on vessels 20 meters or longer be separated by at least half the vessel's length (not exceeding 100 meters), with the forward no more than one-quarter of the length from the stem; sidelights must be positioned at or near the sides of the vessel, forward of the masthead lights. Screens for sidelights consist of matt black sectors to prevent overlap, and shapes such as balls, cones, cylinders, and diamonds must be black, rigid, and of uniform cross-section, with a minimum of 0.6 meters and vertical spacing of at least 1.5 meters (reduced for vessels under 20 meters). colors adhere to CIE coordinates, and intensity is calculated using the formula I=3.43×106×T×D2×K−DI = 3.43 \times 10^6 \times T \times D^2 \times K^{-D}, where T=2×10−7T = 2 \times 10^{-7} is the threshold of vision, K=0.8K = 0.8 accounts for atmospheric transmission, and DD is the range in nautical miles; for example, a masthead requires at least 94 candelas for 6-mile . Horizontal sectors ensure uniform intensity within defined arcs (e.g., sidelights 112.5 degrees each), decreasing to half outside by 1-3 degrees, while vertical sectors maintain minimum intensity within ±5 degrees of horizontal, dropping to 60% within ±7.5 degrees. Amendments in clarified positioning for lights on smaller vessels. Annex II specifies additional signals for fishing vessels operating in close proximity, using lights and shapes to indicate specific activities without conflicting with primary signals under Rule 26. These signals are placed for maximum visibility, separated by at least 0.9 vertically, and visible for 1 , positioned below the all-round lights required for vessels. For trawlers at least 20 in , nets is signaled by two all-round white lights in a vertical line; hauling nets by one white light above one red all-round light in a vertical line; and a net fast upon an obstruction by two all-round red lights in a vertical line. Pair trawlers additionally use a directional forward toward the partner vessel during operations. Purse seiners hampered by their gear display two all-round yellow lights in a vertical line, flashing alternately every second. Trawlers under 20 may exhibit a single all-round white light to indicate or hauling, or two red lights for obstructions. Annex III details the technical specifications for sound signal appliances, including whistles, bells, and s, with requirements scaled by vessel size to ensure audibility ranges. Vessels of 12 meters or more in length must carry a and a bell, while those of 100 meters or more add a ; operate at frequencies between 70 and 700 Hz, with fundamental frequencies limited to 70-200 Hz for vessels 200 meters or longer, 130-350 Hz for 75-200 meters, and 250-700 Hz for under 75 meters. levels are at least 143 dB at 1 meter for vessels 200 meters or longer (2-nautical-mile range), 138 dB for 75-200 meters (1.5 miles), 130 dB for 20-75 meters (1 mile), 120 dB for 12-20 meters (0.5 miles), and 110 dB for under 12 meters (0.25 miles). Directional properties limit drops to 4 dB within ±45 degrees of ahead and 10 dB elsewhere, with positioning as high as practicable to avoid exceeding 110 dB(A) at bridge listening posts. Bells and must produce at least 110 dB at 1 meter, with bells having a mouth diameter of at least 300 mm for vessels over 20 meters (200 mm for 12-20 meters), corrosion-resistant construction, and strikers of at least 3% of the bell's mass. Multiple on larger vessels must differ in frequency by at least 10 Hz if spaced over 100 meters. Annex IV lists standardized distress signals for vessels in need of assistance, cross-referenced to the International Convention for the Safety of Life at Sea (SOLAS) for comprehensive implementation. These include a or other explosive signal fired at intervals of about a minute; continuous sounding of the fog signal; rockets or shells throwing red stars at short intervals; the radiotelegraph or radiotelephone alarm signal; the spoken word "" repeated three times; the distress message N.C.; a square flag with a ball above or below; flames on the vessel such as from a burning tar barrel; a red parachute rocket or hand flare; an orange smoke signal; slowly and repeatedly raising and lowering outstretched arms; and a distress alert by means of (DSC) transmitted on VHF channel 70 or MF/HF frequencies, or by means of satellite communication (e.g., distress alerts), added by amendments adopted in 2007 (effective 1 December 2009). Amendments in 1987 added approved radio-transmitted signals to Annex IV. No distress signal may be used for any other purpose, and signals likely to be confused with them are prohibited.

Operational Guidelines

Conduct in Different Visibility Conditions

In conditions of good visibility, vessels are required to maintain their course and speed when there is no immediate risk of collision, allowing for predictable while using all available means, such as and bearings, to determine if such risk is developing under Rule 7 of the COLREGS. This approach ensures steady progress unless early action is necessary to comply with rules, emphasizing the use of systematic to assess relative motion and avoid assuming constant speed or course by other vessels. When vessels are in sight of one another, as defined in Section II of Part B (Rules 11–18), visual cues become the primary means of assessing collision risk, overriding reliance on instruments alone. In head-on situations involving power-driven vessels under Rule 14, both must alter course to starboard so as to pass on the port side of each other, promoting mutual avoidance through symmetric action. For crossing paths under Rule 15, the vessel that has the other on its own starboard side acts as the give-way vessel and must take early and substantial action to keep clear, avoiding crossing ahead of the stand-on vessel. Stand-on vessels maintain course and speed but must maneuver if it becomes apparent that the give-way vessel is not taking appropriate action, as per Rule 17. In restricted visibility, governed by Section III (Rule 19), vessels must proceed at a safe speed adapted to prevailing conditions, with power-driven vessels maintaining engines ready for immediate maneuvers to allow the longest possible stopping distance. A proper look-out by sight and hearing must be continuously posted, and upon detecting another vessel by or otherwise in close quarters or with risk of collision, the vessel must take action to avoid it—such as altering course or slowing down—while avoiding alterations to for vessels forward of the beam except in scenarios. If a fog signal is heard forward of the beam, speed should be reduced to the minimum at which the vessel can be kept on course or, if necessary, the engines stopped and conducted with extreme caution until the risk passes. Bold maneuvers that might confuse other vessels are prohibited, prioritizing cautious and positive actions. Special adaptations apply to certain vessel types across visibility conditions; for instance, fishing vessels must signal their activities but remain obligated to avoid endangering power-driven vessels under Rule 18, while power-driven vessels assess relative motion using all available data to determine give-way responsibilities. Sound and light signals from Parts C and D may supplement these actions in restricted visibility to alert others of presence or intentions. Best practices underscore constant vigilance, with operators never assuming that other vessels will observe the rules or comprehend signals, thereby fostering proactive in all scenarios.

Collision Avoidance Actions

Vessels engaged in must prioritize proactive measures to assess and mitigate collision risks, as outlined in the International Regulations for Preventing Collisions at Sea (COLREGS). These actions emphasize the use of all available means for detection and the prompt execution of maneuvers that ensure safe passage, rather than relying solely on assigned privileges. Central to this framework is the obligation for every vessel to maintain a safe speed at all times, allowing for effective collision avoidance and stopping within prevailing conditions. Safe speed is determined contextually, without a fixed numerical , by considering factors such as , traffic density (including fishing vessels), the vessel's maneuverability (e.g., stopping distance and turning ability), environmental conditions like wind, , current, and navigational hazards, as well as water depth relative to draft. For vessels equipped with operational , additional considerations include the equipment's characteristics, range scale limitations, interference from weather or , the potential for undetected small objects or , the positions and movements of detected vessels, and enhanced assessments via . This approach ensures vessels can respond adeptly across varying conditions, such as restricted where becomes particularly vital. Risk assessment forms the foundation of collision avoidance, requiring every vessel to employ all appropriate means—visual, auditory, and technological—to determine if a exists, with any doubt treated as affirmative. , if available and operational, must be used systematically, including long-range scanning for early warnings and plotting or equivalent observations of objects; assumptions based on incomplete data, especially sparse information, are prohibited. A key indicator of is a constant bearing of an approaching vessel, signifying no appreciable change; however, may persist even with some bearing alteration, particularly near large vessels, tows, or in close quarters. The general duty to take action to avoid collision mandates positive, timely maneuvers in accordance with COLREGS, guided by good principles. Alterations in course or speed must be substantial and evident to others via visual or observation, avoiding incremental changes; where sea room permits, a significant course alteration alone can effectively prevent close-quarters situations without creating new ones. Vessels must ensure actions result in a safe passing distance, continually verifying effectiveness until clear, and slacken speed, stop, or reverse propulsion if needed to assess or avert danger. Additionally, vessels required not to impede others must act early to provide ample sea room, maintaining full compliance even in risk scenarios. In encounters involving potential collision, specific duties delineate responsibilities: in crossing situations between power-driven vessels, the give-way vessel—defined as the one with the other on its starboard side—must keep out of the way and, if possible, avoid crossing ahead. The give-way vessel's action must be early and substantial to remain well clear, particularly when , where it bears the ongoing obligation to keep clear regardless of other rules. Conversely, the stand-on vessel must initially maintain its course and speed but may maneuver alone if the give-way vessel fails to act appropriately; in imminent danger, it must take the best action to aid avoidance, such as in crossing cases where portward turns are discouraged if circumstances allow. These obligations underscore that no vessel is absolved of proactive avoidance, even when holding stand-on status.

Traffic Separation Schemes

Traffic separation schemes (TSS) are organized systems of one-way traffic lanes separated by defined zones, designed to regulate vessel movement in congested maritime areas and adopted by the (IMO) under Rule 10 of the International Regulations for Preventing Collisions at Sea (COLREGS). These schemes typically consist of traffic lanes for opposing flows, separation zones to buffer them, and sometimes inshore zones for local traffic, ensuring vessels maintain directional flow to prevent head-on encounters. Prominent examples include the TSS in the Dover Strait, the world's busiest shipping lane connecting the to the , first established in 1967 on a voluntary basis and made mandatory by IMO in 1971, and revised multiple times for safety, and the extensive scheme in the Straits of Malacca and Singapore, implemented to manage high volumes of traffic between the and . Vessels navigating within a TSS must proceed in the designated traffic lane in the general direction of flow, staying as close as safely possible to the outer limit on their starboard side. Joining or leaving a lane should occur at its termination points to avoid disrupting flow, and while crossing lanes is permitted when necessary, vessels must do so at a large angle—ideally as close to right angles as practicable—to the direction of traffic and remain on their starboard side of the lane. Vessels not using the TSS, such as those crossing or operating nearby, must avoid the scheme if possible and, if crossing, pass well clear while adhering to these angular guidelines. Certain activities are prohibited within TSS lanes and separation zones to maintain orderly : vessels must not , , or engage in any operation that could impede passage. Specifically, a vessel engaged in shall not impede the passage of any vessel following a lane, reinforcing the priority of through-. Vessels less than 20 meters in length, vessels, and those engaged in are exempt from joining the main lanes but must still avoid impeding larger power-driven vessels using them; these smaller vessels may utilize any designated inshore zone if available. Safe navigation in TSS relies on continuous monitoring using and (AIS) to track other vessels and maintain , particularly in high-density areas. Masters are required to report any deviations from the scheme, such as emergencies or necessary maneuvers, to relevant authorities in schemes with mandatory reporting, like the Dover Strait. TSS are periodically reviewed and amended by IMO through resolutions from the Maritime Safety Committee, incorporating navigational data and incident analyses to enhance effectiveness. By segregating opposing traffic flows, TSS significantly reduce the risk of head-on collisions and other encounters in high-traffic international straits, contributing to overall maritime safety as evidenced by lower incident rates in adopted areas compared to unregulated routes. These schemes integrate with broader collision avoidance principles by providing structured pathways that complement ad-hoc maneuvers under other COLREGS rules.

Implementation and Enforcement

International Ratification Process

The Convention on the International Regulations for Preventing Collisions at Sea (COLREGs), 1972, is administered by the (IMO), which serves as the and oversees its implementation globally. Adopted at an IMO diplomatic conference in on 20 October 1972, the convention entered into force on 15 July 1977, twelve months after at least 15 states—whose combined merchant fleets accounted for not less than 65% of the world's of vessels over 100 gross tons—had or acceded to it. As of 2025, 164 states are contracting parties to the COLREGs, encompassing approximately 98.7% of global merchant shipping tonnage; this near-universal coverage ensures widespread applicability, with non-party jurisdictions like effectively adopting the rules through domestic legislation to maintain interoperability with international shipping. Amendments to the convention are handled through the IMO's Maritime Safety Committee (MSC), which proposes changes based on technical and safety needs; these are subject to the tacit acceptance procedure, under which an amendment is automatically adopted if no objections are raised by at least one-third of contracting states or by states representing 50% of the convention's within a specified timeframe, often resulting in adoption via silence from 80% or more of parties. Entry into force for amendments generally occurs 18 to 24 months after , providing states time to incorporate updates into national laws and train personnel. For significant structural changes, periodic diplomatic conferences have been convened, with the most recent in addressing consolidation of the rules and annexes to reflect accumulated amendments. The IMO monitors compliance through its Sub-Committee on Implementation of IMO Instruments (III), which conducts audits and reviews to ensure adherence, while interim updates and clarifications are disseminated via MSC circulars to guide uniform application without requiring full cycles.

National Jurisdictions and Variations

In the United States, the International Regulations for Preventing Collisions at Sea (COLREGS) are incorporated into domestic law through Title 33 of the (CFR), specifically Parts 80 through 83, which unify the application of international and rules. Part 80 establishes demarcation lines separating waters subject to COLREGS (generally offshore and connected navigable waters) from those governed by inland rules, ensuring consistent application across jurisdictions. The (USCG) enforces these regulations, with authority to issue certifications and exemptions where necessary to accommodate specific vessel operations while maintaining overall compliance. In the , COLREGS are implemented via the Merchant Shipping (Distress Signals and Prevention of Collisions) Regulations 1996, which fully adopt the international rules as amended, applying them to all vessels on the high seas and connected navigable waters. The (MCA) provides oversight, issuing guidance such as Merchant Shipping Notice (MSN) 1781 to clarify application and ensure alignment with international standards. This framework emphasizes uniform enforcement without significant deviations from the core COLREGS provisions. Canada harmonizes COLREGS through the Collision of Vessels Regulations (SOR/2000-346), which mirror the international rules while incorporating modifications tailored to national contexts, including specific provisions for the . For instance, in Canadian waters of the , additional requirements address unique environmental and traffic conditions, such as modified lighting for exploration vessels and sound signals adapted to regional geography, ensuring safe navigation in these confined, high-traffic areas. oversees implementation, promoting consistency with the international convention. In Turkey, the International Regulations for Preventing Collisions at Sea (COLREGS 1972) apply in territorial waters and are binding on all ships, including foreign-flagged vessels, through incorporation into Turkish maritime law following ratification in 1980. As major flag states, and the have fully adopted COLREGS into their national legislation, reflecting their roles in global shipping. Singapore's Merchant Shipping (Prevention of Collisions at Sea) Regulations directly transpose the rules, with the Maritime and emphasizing to verify compliance by foreign vessels entering its waters. Similarly, the Republic of the integrates COLREGS via its Maritime Regulations (MI-108), mandating adherence for all registered vessels under the responsibilities outlined in IMO conventions. Both jurisdictions prioritize rigorous inspections to uphold international standards. National variations often arise in inland waters, where governments may establish local rules under COLREGS Rule 1(d) to address specific navigational challenges. For example, in the Republic of Korea, the Maritime Safety Act permits modifications for rivers like the Han River, including speed limits and traffic segregation to manage recreational and commercial traffic in urban inland areas. Military exemptions are common across jurisdictions; while COLREGS apply to warships, national laws frequently allow deviations for operational needs, provided they do not compromise safety, as seen in U.S. Navy certifications under 33 CFR Part 82. Globally, COLREGS enjoy near-universal alignment, with 164 contracting states as of , covering approximately 98.7% of world , and minimal updates anticipated in beyond routine amendments to related IMO instruments. This widespread ratification, building on the international process, facilitates seamless maritime operations across borders.

Compliance Mechanisms and Penalties

Compliance with the International Regulations for Preventing Collisions at Sea (COLREGS) is primarily enforced through a combination of responsibilities and (PSC) mechanisms. Flag states conduct surveys to ensure vessels meet technical requirements, such as the proper construction, positioning, and installation of lights and shapes as outlined in Annex I of the COLREGS. These surveys verify that equipment complies with the standards set by the state whose the vessel flies, helping to prevent navigational hazards before vessels enter . Port state control provides an additional layer of oversight by allowing coastal states to inspect foreign-flagged vessels in their ports to confirm adherence to international conventions, including COLREGS. Under frameworks like the Memorandum of Understanding (MoU), PSC officers can detain non-compliant ships if deficiencies in navigation lights, signals, or other COLREGS-related equipment are found, preventing substandard vessels from continuing operations. For instance, inspections may include checks on systems and visual signaling devices to ensure they align with COLREGS rules for collision avoidance. Training requirements form a cornerstone of COLREGS compliance, mandated by the International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW). Deck officers must demonstrate knowledge of COLREGS through competence standards in Table A-II/1 of the STCW Code, which requires applying watchkeeping principles and collision prevention rules during navigation. This includes understanding responsibilities under Rule 2, which holds masters, owners, and crew accountable for safe navigation. Simulator-based training is widely used to reinforce these skills, allowing officers to practice COLREGS application in realistic scenarios like separation schemes and restricted . Penalties for COLREGS violations vary by jurisdiction but emphasize deterrence through civil and criminal sanctions. , civil penalties under 33 U.S.C. § 1608 can reach up to $18,610 per violation for negligent operations endangering life or property, as adjusted for inflation in 2025. For collisions resulting in death, criminal liability may arise under the Seaman's Manslaughter Act (18 U.S.C. § 1115), imposing up to 10 years imprisonment for willful or negligent conduct breaching COLREGS. Civil damages from such incidents are subject to limitation under the 1976 Convention on Limitation of Liability for Maritime Claims (LLMC), which caps owner liability for and claims while allowing courts to allocate fault based on COLREGS adherence. Monitoring technologies and international audits further support enforcement. Automatic Identification Systems (AIS) and Voyage Data Recorders (VDR) provide real-time tracking and post-incident data for analyzing COLREGS compliance, such as adherence to safe speeds and collision avoidance maneuvers. The (IMO) conducts flag state audits under the Member State Audit Scheme (IMSAS), established by Resolution A.1067(28), to verify effective implementation of COLREGS through the IMO Instruments Implementation Code (III Code). These audits evaluate administrative processes, surveys, and enforcement, with findings reported in Consolidated Audit Summary Reports to identify gaps in compliance. Overall, COLREGS compliance remains high due to strong incentives from maritime insurance providers, who often void or limit coverage for claims involving rule violations, encouraging operators to prioritize adherence. However, incidents like the 2017 collision between the USS Fitzgerald and ACX Crystal underscore persistent gaps, where failures in and COLREGS application led to seven fatalities and over $300 million in damage, prompting reviews of training and oversight.

Special Considerations

No Right of Way Principle

The International Regulations for Preventing Collisions at Sea (COLREGS), particularly Rule 2 on responsibility, establish that no vessel holds an absolute right of way that absolves it from the duty to avoid collisions. Under Rule 2(a), nothing in the regulations exonerates any vessel, owner, master, or crew from the consequences of neglecting to comply with the rules or failing to take precautions required by ordinary seamanship or special circumstances. Rule 2(b) further requires that all dangers of navigation and collision be considered, allowing departures from the rules if necessary to avert immediate danger, thereby imposing a shared obligation on all vessels to act preventively regardless of designated roles. Complementing this, Rule 8 mandates that any action to avoid collision be positive, timely, and substantial, ensuring a safe passing distance, and emphasizes that even vessels with priority must monitor the effectiveness of maneuvers and adjust if needed. This principle marks a departure from earlier maritime rules, which originated in 18th- and 19th-century conventions that enforced strict hierarchies, such as starboard-tack vessels having priority over port-tack ones, or steamships maintaining course under 1863 international agreements and the 1897 Washington Conference revisions. Those frameworks prioritized rigid adherence to maintain order in sail-driven eras but often led to collisions when exceptions were not permitted. The 1972 COLREGS, adopted by the , shifted the philosophy toward proactive prevention, allowing stand-on vessels to act earlier and integrating modern factors like powered and traffic density to prioritize safety over inflexible privileges. Illustrative examples underscore this shared duty. Under Rule 17, a stand-on vessel must initially maintain course and speed but is required to maneuver alone if it becomes apparent that the give-way vessel is not complying, thereby preventing reliance on assumed priority. Similarly, a vessel engaged in , which yields to nearly all others under Rule 18, must still exercise caution to avoid impeding safe passage and take all necessary actions per Rule 2, even without a formal to yield in every . These provisions ensure that no vessel can invoke status to justify inaction. In legal contexts, particularly U.S. admiralty courts applying COLREGS, violations lead to fault apportionment based on rather than equal division by default. The landmark Supreme Court decision in United States v. Reliable Transfer Co. (1975) established proportional liability, but courts frequently assign 50/50 responsibility when both parties are equally negligent in failing to avoid collision, as seen in cases involving mutual disregard of stand-on and give-way duties. This reinforces the regulations' intent by holding all parties accountable. Maritime training programs emphasize the axiom "no privilege in peril," highlighting that COLREGS impose responsibilities, not rights, to foster a culture of vigilance among operators. This ties briefly to broader operational guidelines on collision avoidance actions, where early intervention is paramount.

Application to Racing and Non-Commercial Vessels

The International Regulations for Preventing Collisions at Sea (COLREGS) apply universally to all vessels, including those engaged in racing and non-commercial operations, with a particular emphasis on Parts A (General) and B (Steering and Sailing Rules), which establish fundamental principles for collision avoidance without any blanket exemptions for recreational or competitive craft. This ensures that racing sailboats and non-commercial vessels, such as small yachts, maintain compliance during interactions with other traffic, prioritizing safety over competitive maneuvers. For racing vessels, the Racing Rules of Sailing (RRS) serve as a supplement to COLREGS, applying primarily between boats actively while deferring to COLREGS when a racing boat encounters a non-racing vessel to prevent collisions. Specifically, RRS Rule 14 requires boats to avoid contact if reasonably possible, aligning with COLREGS Rule 14, and the hierarchies in RRS Part 2 (e.g., port-starboard and windward-leeward rules) mirror COLREGS rules for vessels in open water, ensuring deference to international standards during potential collision risks. In cases of actual collision, investigations invoke COLREGS to assess fault, as seen in the 2018 Volvo Ocean Race incident involving 11th Hour Racing, where a nighttime collision with a prompted an independent review emphasizing COLREGS compliance in high-traffic areas. Non-commercial vessels, including small yachts and sailboats, follow tailored COLREGS provisions for visibility and equipment to accommodate their scale and operations. Under Rule 25, a sailing vessel less than 7 meters in length must, if practicable, exhibit sidelights and a sternlight; otherwise, it shall have ready an all-round white light (such as from a or ) to signal its presence and prevent collisions. Vessels under oars, common in non-commercial , may optionally show sailing vessel lights but must otherwise display an all-round white light ready for use, reinforcing the regulation's focus on minimal yet effective signaling for small craft. Race organizers promote best practices by publishing special regulations that align with COLREGS, such as the Offshore Special Regulations (OSR), which mandate navigation lights per COLREGS Part C and require adherence to traffic separation schemes while yielding to commercial traffic. These guidelines ensure that racing events incorporate collision avoidance protocols, including enhanced lighting and maneuvering training, to mitigate risks without overriding core COLREGS obligations.

Exemptions and Local Rules

The International Regulations for Preventing Collisions at Sea (COLREGS) provide limited exemptions to accommodate specific vessel types and operational needs, while emphasizing universal compliance to ensure safety. Under Rule 1(c), governments may establish special rules for ships of war and vessels proceeding under , allowing additional station or signal lights, shapes, or whistle signals that do not mimic those authorized elsewhere in the rules. These provisions enable naval vessels to maintain operational effectiveness without compromising navigational safety, though they remain fully subject to the core principles of collision avoidance. Naval vessels, like all others, may deviate from strict rule adherence only when immediate danger requires it, as outlined in Rule 2(b), provided such actions consider prevailing circumstances, vessel limitations, and the imperative to avoid collisions. In practice, the U.S. Department of the Navy certifies alternative light and shape placements for certain classes of warships due to their special construction, ensuring the closest possible compliance while notifying the (IMO) of these arrangements. Any deviation must prioritize safety and use clear international signals to prevent confusion with civilian traffic. For vessels of special construction or purpose that cannot fully comply with lighting, shape, or sound signaling requirements, Rule 1(e) permits alternative arrangements determined by the government, as long as they align with the rules' general intent and avoid misleading other vessels. Flag states must communicate these alternatives to the IMO, which disseminates them to all contracting governments; such exemptions are granted solely for practical necessity, not convenience, and persistent deviations require ongoing notification to maintain transparency. Local rules supplement COLREGS in , harbors, rivers, lakes, and connected inland waterways navigable by seagoing vessels, as authorized by Rule 1(b), provided they conform as closely as possible to the international standards. , the Rules (33 CFR Part 83) apply within demarcation lines separating inland and , featuring differences such as modified sound signals for in narrow channels and alternative for power-driven vessels under 12 meters in length, which may display a single all-round white light instead of separate masthead and sternlights. Specific protocols also govern interactions with bridges and tunnels; for instance, under U.S. Inland Rule 34(i), a vessel approaching a bridge shall reduce its speed sufficiently to avoid creating a dangerous wash and shall navigate with particular caution until the bridge has been passed, while signals to request bridge openings are prescribed in 33 CFR Part 117 (e.g., five short blasts). Pilotage operations adhere to COLREGS, with pilots required to apply the rules while leveraging local knowledge to enhance safe navigation in confined or complex areas. The master retains ultimate responsibility, but the pilot's expertise allows for rule-compliant maneuvers tailored to site-specific hazards, such as currents or traffic patterns in ports. In the European Union, inland waterways employ the European Code for Signs and Signals on Inland Waterways (CEVNI), developed under the United Nations Economic Commission for Europe (UNECE), which harmonizes collision prevention measures with COLREGS through standards set by the European Committee for drawing up Standards in the field of Inland Navigation (CESNI). These rules address unique inland challenges, like lock passages and convoy formations, while aligning signaling and conduct provisions to facilitate cross-border navigation.

References

  1. https://www.imo.org/en/about/conventions/pages/colreg.aspx
  2. https://treaties.un.org/pages/showDetails.aspx?objid=08000002800fcf87
  3. https://www.navcen.uscg.gov/sites/default/files/pdf/navRules/navrules.pdf
  4. https://www.samgongustofa.is/media/log-og-reglur/COLREG-Consolidated-2018.pdf
  5. https://wwwcdn.imo.org/localresources/en/About/Conventions/StatusOfConventions/Status%202025.pdf
  6. https://formularus-verlag.de/wp-content/uploads/2024/12/IMO_ColRegs.pdf
  7. https://maritimesafetyinnovationlab.org/wp-content/uploads/2020/10/History_of_the_Collision_Regulations.pdf
  8. https://www.imo.org/en/About/Conventions/Pages/International-Regulations-for-Preventing-Collisions-at-Sea-(COLREG).aspx
  9. https://www.imo.org/en/About/Conventions/Pages/COLREG.aspx
  10. http://www.admiraltylawguide.com/conven/collisions1910.html
  11. https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/AssemblyDocuments/A.464%28XII%29.pdf
  12. https://www.imo.org/en/OurWork/Safety/Pages/WIG.aspx
  13. https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/AssemblyDocuments/A.1004%2825%29.pdf
  14. https://www.imo.org/en/ourwork/safety/pages/preventing-collisions.aspx
  15. https://www.cambridge.org/core/journals/journal-of-navigation/article/study-on-the-development-and-trend-of-colregs-a-broader-perspective/F5447826FB4BA371031EE1A663090125
  16. https://www.imo.org/en/OurWork/Safety/Pages/ShipsRouteing.aspx
  17. https://www.westpandi.com/globalassets/news/safe-passage---the-straits-of-malacca-and-singapore.pdf
  18. https://www.gov.uk/government/publications/mgn-364-mf-amendment-2-navigation-safety-traffic-separation-schemes-application-of-rule-10-and-navigation-in-the-dover-strait/mgn-364-mf-amendment-2-navigation-safety-traffic-separation-schemes-application-of-rule-10-and-navigation-in-the-dover-strait
  19. https://www.imo.org/en/About/Conventions/Pages/StatusOfConventions.aspx
  20. https://www.imo.org/en/About/Conventions/Pages/Default.aspx
  21. https://www.ecfr.gov/current/title-33/chapter-I/subchapter-D/part-80
  22. https://www.navcen.uscg.gov/navigation-rules-amalgamated
  23. https://www.ecfr.gov/current/title-33/chapter-I/subchapter-E/part-83
  24. https://www.legislation.gov.uk/uksi/1996/75/made
  25. https://assets.publishing.service.gov.uk/media/5a7ca25340f0b65b3de0a2bc/msn1781.pdf
  26. https://cebioglu.av.tr/new-regulation-on-prevention-of-maritime-collision-has-entered-into-force-in-turkiye/
  27. https://sso.agc.gov.sg/SL/MSA1995-RG10
  28. https://www.register-iri.com/wp-content/uploads/MI-108.pdf
  29. https://elaw.klri.re.kr/eng_service/lawView.do?hseq=62194&lang=ENG
  30. https://www.federalregister.gov/documents/2018/06/19/2018-13124/certifications-and-exemptions-under-the-international-regulations-for-preventing-collisions-at-sea
  31. https://www.ecolregs.com/index.php?option=com_k2&view=item&layout=item&id=118&Itemid=499&lang=en
  32. https://www.imo.org/en/OurWork/Safety/Pages/Preventing-collisions.aspx
  33. https://parismou.org/PMoU-Procedures/Lybrary/port-state-control-inspections-paris-mou
  34. https://www.imo.org/en/ourwork/humanelement/pages/stcw-convention.aspx
  35. https://www.edumaritime.net/stcw-code/stcw-ii-1-oicnw
  36. https://www.mitags.org/course/watchkeeping-operational-level/
  37. https://www.federalregister.gov/documents/2025/01/02/2024-31204/civil-monetary-penalty-adjustments-for-inflation
  38. https://forum.gcaptain.com/t/seamans-manslaughter-act/57649
  39. http://www.admiraltylawguide.com/conven/limitation1976.html
  40. https://www.imo.org/en/ourwork/safety/pages/ais.aspx
  41. https://www.imo.org/en/OurWork/Safety/Pages/VDR.aspx
  42. https://www.imo.org/en/OurWork/MSAS/Pages/default.aspx
  43. https://www.youtube.com/watch?v=WoFlAUcEAcI
  44. https://www.ntsb.gov/investigations/AccidentReports/Reports/MAR2101.pdf
  45. https://www.sailing.org/racingrules/
  46. https://www.sailing.org/document/rrs-2025-2028/
  47. https://archive.theoceanrace.com/en/news/11191_Volvo-Ocean-Race-initiate-independent-report.html
  48. https://www.navcen.uscg.gov/sites/default/files/pdf/navRules/Rules20-31.pdf
  49. https://www.sailing.org/document/world-sailing-offshore-special-regulations-2023-2024/
  50. https://www.pacom.mil/Portals/55/Documents/Legal/J06%20TACAID%20-%20COLREGS%20-%20FINAL.pdf
  51. https://www.ecfr.gov/current/title-33/chapter-I/subchapter-J/part-117
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