The Structure of the COLREGS and Why It Matters in Command
The International Regulations for Preventing Collisions at Sea 1972 (COLREGS), enacted in UK law via the Merchant Shipping (Distress Signals and Prevention of Collisions) Regulations 1996, apply to all vessels upon the high seas and connecting waters navigable by seagoing vessels. As Master, you are personally responsible for ensuring they are applied — not merely observed passively by the OOW.
MSN 1858 Amendment 2 and Yacht Certificates
For candidates seeking a yacht-restricted Certificate of Competency, MSN 1858 Amendment 2 confirms that a dedicated oral examination is required, in which the examiner verifies thorough knowledge of the COLREGS. This lesson is therefore directly examinable: you must be able to apply every part of the rules with professional judgement, not merely recite them.
The Five Parts and Their Logic
Part A — General (Rules 1–3) establishes scope and definitions. Rule 3 defines terms such as 'vessel not under command', 'restricted in her ability to manoeuvre', and 'seaplane'. You must know these precisely: a vessel's status under Rule 3 determines which lights, shapes, and sound signals she displays, and which manoeuvring hierarchy she sits in.
Part B — Steering and Sailing Rules (Rules 4–19) is the operational heart of the COLREGS. It is split into three sections:
Section I (Rules 4–10): applies in any visibility. Rule 10 governs TSS conduct — a yacht transiting a lane must proceed in the general direction of traffic flow and, as far as practicable, keep clear of a separation zone.
Section II (Rules 11–18): applies in sight of one another. The give-way / stand-on hierarchy builds logically: a vessel with the least manoeuvrability takes the highest precedence. Rule 18 opens with an important chapeau: except where Rules 9, 10 and 13 otherwise require — meaning narrow channels, traffic separation schemes, and overtaking situations can override Rule 18's hierarchy. The rule then sets out obligations by vessel type:
Rule 18(a) — A power-driven vessel underway shall keep out of the way of: (i) a vessel not under command (NUC); (ii) a vessel restricted in her ability to manoeuvre (RAM); (iii) a vessel engaged in fishing; (iv) a sailing vessel.
Rule 18(b) — A sailing vessel underway shall keep out of the way of: (i) a vessel not under command; (ii) a vessel restricted in her ability to manoeuvre; (iii) a vessel engaged in fishing.
Rule 18(c) — A vessel engaged in fishing underway shall, so far as possible, keep out of the way of: (i) a vessel not under command; (ii) a vessel restricted in her ability to manoeuvre.
Rule 18(d) — Any vessel other than a NUC or RAM shall, if the circumstances of the case admit, avoid impeding the safe passage of a vessel constrained by her draught (CBD), which shall navigate with particular caution. Note the examiner trap: Rule 18(d) concerns constrained-by-draught vessels, not sailing vessels. The obligation here is to avoid impeding — a distinct and lesser duty than the give-way obligation imposed in paragraphs (a)–(c).
Rule 18(e) — A seaplane on the water shall, in general, keep well clear of all vessels and avoid impeding their navigation.
Rule 18(f) — A WIG craft shall, when taking off, landing, and in flight near the surface, keep well clear of all other vessels and avoid impeding their navigation; in all other circumstances the WIG craft complies with the Rules as a power-driven vessel.
A second examiner trap: a sailing vessel under engine is a power-driven vessel for COLREGS purposes (Rule 3(b)) and accordingly sits in Rule 18(a)'s hierarchy — she must keep clear of NUC, RAM, fishing vessels, and sailing vessels.
Section III (Rule 19): restricted visibility only. No vessel is ever 'stand-on' in fog. Every vessel proceeds at a safe speed, has engines ready, and takes early avoiding action if a close-quarters situation may develop.
Part C — Lights and Shapes (Rules 20–31) defines what must be shown and when. Lights are mandatory between sunset and sunrise and in restricted visibility. Shapes are displayed by day. As Master you must be able to identify any combination presented to you.
Part D — Sound and Light Signals (Rules 32–37) covers manoeuvring signals, fog signals, and distress signals. Rule 37 cross-references Annex IV.
Part E and the Annexes deal with exemptions and technical specifications for equipment positioning and arc of visibility.
Intent: Good Seamanship as the Constant Thread
The COLREGS are not a rigid sequence of if/then rules. Rule 2 — often called the 'General Prudential Rule' — makes it explicit: nothing in the rules exonerates any vessel from the consequences of neglecting any precaution required by the ordinary practice of seamen. Rule 8 requires any action to avoid collision to be positive, made in ample time, and result in passing at a safe distance. Rule 16 requires a give-way vessel to take early and substantial action.
In the oral exam, the examiner is testing whether you apply the rules with judgement, not whether you can recite them. Always answer in terms of what you as Master would direct.