Chapter 2: Where the Rules Came From
This chapter is only worth including if it explains the text you read today. The history of the collision regulations is long and not very dramatic. So this chapter sticks to the moments where a problem in the old rules led to a feature in the Rules you use now. If you ever wonder why the Rules are worded the way they are, some of the answers are here.
Customs before statutes
For several centuries, avoiding collisions at sea relied on local custom and the judgement of each master. Custom worked well enough when ships were slow, traffic was thin, and most encounters happened in familiar waters. There, a master knew the habits of other local vessels, and the geography limited the shapes an encounter could take. Steam propulsion spread in the early nineteenth century, and all three of those conditions started to break down at once. Steam vessels were faster than sail and less predictable in their paths. Traffic grew. And vessels now met strangers over a much wider area. Collision rates rose to match. Local custom already varied from port to port, and it was plainly not enough.
The response was legislation. In 1840 the London Trinity House drafted regulations for steam vessels, and Parliament enacted them in 1846. They were minimal. A steam vessel in a narrow channel was to leave another vessel on her own port hand, and two steam vessels on crossing courses were to alter to starboard. In 1848 the same Act was extended to require lights: green and red sidelights and a white masthead light. Any OOW today would still recognise that combination at once (Cockcroft & Lameijer, 7th ed, History of the Collision Regulations).
The 1863 Articles and the core of the current rules
The Trinity House rules applied only in British waters. The problem of international uniformity remained. A vessel following British custom could meet a foreign vessel following completely different local practice, and neither would know what the other was about to do. In 1863 a new set of rules came into operation, drawn up by the British Board of Trade with the French Government. By the end of 1864 more than thirty maritime countries had adopted them, including the United States and Germany (Cockcroft & Lameijer, 7th ed, History of the Collision Regulations). These rules are known as the Articles. Reading them is striking, because the core of the current rules is already there.
The 1863 Articles required crossing vessels to give way based on which side the other vessel was on. They required steam vessels meeting head-on to alter to starboard. They established that every overtaking vessel keeps out of the way of the vessel being overtaken. And they required the stand-on vessel to hold her course. These four principles are Rules 15, 14, 13 and 17 of the 1972 Regulations, in direct descent. The crossing rule and the overtaking rule have not changed in their basics in over 160 years.
PRACTICAL NOTE: why this matters
When candidates ask why the Rules are the way they are, the most accurate short answer is that the 1863 Articles worked. The basic structure solved enough collisions, often enough, that every later revision kept it. That structure allocates give-way and stand-on by geometry, and it always burdens the overtaking vessel, whatever her aspect. The current rules are not a fresh design. They are a living document, amended over time around a core that has never needed to change.
The Washington Conference and the stand-on rule
At the 1889 International Maritime Conference in Washington, two things were added to the stand-on vessel’s obligations. Both came from a real operational problem. Under the 1863 Articles the stand-on vessel had to keep her course, but nothing was said about speed. This left a gap. A stand-on vessel could hold her heading while stopping engines. That was technically within the rule, but it left the give-way vessel with a target behaving in a way she did not expect. The 1889 Conference added that a stand-on vessel should keep her speed as well as her course (Cockcroft & Lameijer, 7th ed, History of the Collision Regulations).
The Conference also dealt with the give-way vessel’s preferred manoeuvre. Before this she was simply required to keep clear. But mariners had got into the habit of altering to pass ahead of the stand-on vessel. That was faster, but it left almost no margin for error if the alteration came late. Washington 1889 added that a give-way vessel should avoid crossing ahead (Cockcroft & Lameijer, 7th ed, History of the Collision Regulations). That principle survives today in two places: Rule 16’s demand for a substantial alteration taken early enough to be clearly seen, and Rule 15’s geometry, which quietly favours passing astern.
1960: the radar problem
The regulations revised at SOLAS 1948 made no provision for radar, because few vessels carried it then (Cockcroft & Lameijer, 7th ed, History of the Collision Regulations). By the late 1950s radar was widespread, and a new kind of collision had appeared: the radar-assisted collision. Both vessels were aware of each other by radar, but neither took effective action, because the Rules gave no clear framework for how to behave towards a contact seen only on radar and not yet in sight. A series of high-profile collisions in poor visibility, including the Andrea Doria–Stockholm in 1956, made the problem obvious (BR45 Vol 4, para 1004d).
The 1960 SOLAS Conference in London dealt with this. It added a new paragraph to the restricted visibility rules. This allowed early and substantial action to avoid a close-quarters situation with a vessel detected by radar forward of the beam. This is the direct ancestor of Rule 19(d) (Cockcroft & Lameijer, 7th ed, History of the Collision Regulations). Radar had moved faster than the law, and the law caught up, but only in part. The wider question of how to fold radar information into collision-avoidance decisions was still left mostly to seamanship rather than rule.
1967–1972: traffic separation and the big rewrite
The most visible piece of unfinished business from 1960 was traffic separation. By the mid-1960s the Dover Strait had become one of the most dangerous stretches of water in the world. Opposing streams of heavy commercial traffic crossed in restricted space with no formal routing. The British Institute of Navigation set up a working group on the Dover Strait in September 1960. The French and German Institutes joined the following year, a separation scheme was devised, and IMCO recommended the routeing schemes for use by mariners in 1967 (Cockcroft & Lameijer, 7th ed, History of the Collision Regulations). The problem was that the Rules had nothing to say about them.
The 1972 Convention met in London and dealt with this, along with much else, in the most substantial rewrite the regulations have ever had. The changes worth noting, because they explain features of the current text, are the following. All are recorded in the conference history (Cockcroft & Lameijer, 7th ed, History of the Collision Regulations).
The format change. Before 1972, lights, shapes and sound signals came first in the instrument, followed by the steering and sailing rules. The 1972 Convention reversed this. The conduct rules now come before the technical provisions, because the steering and sailing rules are what an OOW applies under pressure. The lights and signals provisions are reference material. The current structure of Parts A, B, C and D reflects a deliberate decision about what a mariner reaches for first.
Technical details moved to Annexes. The 1972 rewrite moved the dimensional and technical specifications for lights, shapes and sound equipment out of the Rules themselves and into Annexes. This recognised that technical standards would need updating as technology changed, and that keeping them in the treaty text made amendment slow and awkward. The current Annexes I to IV are a direct result.
The stand-on rule. Rule 17 in its current form lets a stand-on vessel act to avoid collision at an earlier stage than the 1960 rules allowed. The staged structure of Rule 17 runs: keep course and speed, then may act, then shall act. This reflects both the 1889 addition and a 1972 recognition that earlier action by a stand-on vessel was sometimes necessary, and should be clearly permitted rather than left legally unclear.
Rule 10 for TSS. The 1972 Convention introduced what is now Rule 10, giving traffic separation schemes legal force within the collision regulations for the first time. The specific duties to proceed in the appropriate traffic lane, to cross at right angles, and to avoid anchoring in or near a traffic lane all date from 1972. They are direct responses to the Dover Strait problem (BR45 Vol 4, paras 1004f–h).
New Section I rules. New rules were introduced in 1972 to deal specifically with look-out, safe speed and risk of collision (Rules 5, 6 and 7), alongside the new traffic separation rule. Rule 8, on action to avoid collision, was also substantially recast. For the first time it required that action result in passing at a safe distance (Cockcroft & Lameijer, 7th ed, comment on Rule 8). Before this these obligations were either absent or buried in other provisions. They were placed at the opening of Part B, applying in any condition of visibility before any specific encounter rule. This reflects the drafters’ view that they are foundational obligations, ones that come before and support every situational rule.
Amendments since 1972
The 1972 Regulations came into force in 1977 and have been amended seven times since: in 1981, 1987, 1989, 1993, 2001, 2007 and 2013 (IMO, amendment history of the COLREG Convention). It is the last of these that the edition used throughout this guide incorporates (MISCPUB 0127, cover: “Incorporating December 2013 amendments”). None of these revisions changed the basic structure. They addressed matters such as specialist craft, including wing-in-ground craft, and changes to the agreed international means of showing distress. The core of the instrument was left untouched (BR45 Vol 4, para 1004i).
The core instrument has stayed stable because the 1863 framework and the 1972 structure have proved durable. The Rules are not due for a fundamental revision, and there is no sign one is coming. What an OOW needs to understand is this: the text you are reading is the product of a century and a half of small, steady problem-solving. The odd bits in that text are almost always the mark of a specific past failure, not drafting mistakes.
DRAFTING ISSUE: the 2013 amendments and MISCPUB 0127
The edition of MISCPUB 0127 in the Books of Reference folder incorporates the December 2013 amendments and is current for examination and operational purposes. The 2013 amendments were minor. When consulting any other edition of the Rules, check the amendment record on the inside front cover.
What history teaches
The Rules were built by fixing failures, and that shapes how an OOW should approach apparent gaps or ambiguities in the text. When the Rules say nothing about how to exchange VHF communications during an encounter, or nothing about AIS as a risk-of-collision tool, this is not because the drafters forgot. It is because these technologies came after the current structure, and the law has not yet caught up with them the way 1960 caught up with radar. The seamanship gap remains, as Chapter 10 discusses. The history is useful for exactly this reason: it teaches you to notice where the Rules go silent, and to understand why.
See also: Ch 3 (Rule 1, application and territorial scope), Ch 5 (structure of Parts A–F and Annexes), Ch 10 (good seamanship in the gaps).