Part II: Rule by Rule
This part goes through the Rules in order, explaining what each one means and why it’s written the way it is, not reprinting the text itself (that’s Appendix B). TIER 1 Rules, the ones that carry judgement and produce case law, get full analysis; TIER 2 Rules, the definitional and structural ones, get concise treatment. Each Tier 1 Rule ends with an Interactions line, because no Rule operates alone. Rule references are to MISCPUB 0127; the commentary leans on Cockcroft & Lameijer (7th ed) and BR45 Vol 4. The Foundations chapters in Part I carry the reasoning; Part II applies it Rule by Rule.
Chapter 11: Part A, General (Rules 1 to 3)
Rule 1: Application · TIER 2
Rule 1 sets where and to whom the Rules apply, and Chapter 3 unpacks it in full. In brief: Rule 1(a) makes the Rules apply to all vessels on the high seas and all waters connected to them navigable by seagoing vessels, so the reach is fixed by the water, not the flag. Rule 1(b) preserves special rules made by a local authority for roadsteads, harbours, rivers and inland waters, which must conform as closely as possible to the international Rules. Rule 1(c) lets a government add station or signal lights for warships, convoys and fishing fleets, provided they cannot be mistaken for anything authorised elsewhere. Rule 1(d) gives the Organization power to adopt traffic separation schemes. Rule 1(e) lets a government permit a vessel of special construction to comply as closely as possible where she physically cannot comply fully.
See: Ch 3 (application and territorial scope), Ch 4 (why the RAN holds itself to the Rules).
Rule 2: Responsibility · TIER 1
Rule 2 is the master Rule, and Chapter 10 treats it in full. It does two things. Rule 2(a) is a savings clause: nothing in the Rules exonerates a vessel, owner, master or crew from the consequences of neglecting the Rules, or of neglecting any precaution required by the ordinary practice of seamen or by the special circumstances of the case. Its force is that compliance with the letter is a floor, not a ceiling; if good seamanship required something the Rules did not spell out, the failure to do it is still a fault. Rule 2(b) is the departure limb: it permits, and sometimes compels, a departure from the Rules, but only where there are special circumstances and immediate danger, both together, and only so far as needed to avoid the danger.
TRANSLATION
Rule 2(a) (MISCPUB 0127): “Nothing in these Rules shall exonerate any vessel … from the consequences of any neglect to comply with these Rules or of the neglect of any precaution which may be required by the ordinary practice of seamen, or by the special circumstances of the case.”
Plain reading: keeping to the Rules is not enough; you must also do what a good seaman would.
What the legal wording does that the plain version can’t: “nothing … shall exonerate” preserves your liability against the most tempting defence, that no Rule told you not to. It makes good seamanship a binding standard, not advice.
The phrase “ordinary practice of seamen” is the residual catch-all, capturing what the drafters could not anticipate. Courts have used Rule 2(a) to fix vessels with fault for failures that breach no numbered Rule at all: not using VHF when it would have prevented a misunderstanding, not posting extra lookouts in dense traffic, not reducing speed when another vessel’s intentions were unclear.
DRAFTING ISSUE: the boundary between 2(a) and 2(b)
Rule 2(a) says comply with the Rules and with good seamanship; Rule 2(b) says depart from the Rules when special circumstances and immediate danger require it. The line between a justified departure and a negligent breach is drawn only by a court, after the fact. The protection is to depart only when both conditions are genuinely present, and to carry the burden of showing they were.
Interactions: Rule 2 stands under every other Rule. It can raise the standard above any Rule (2(a)) and, in the narrow case of special circumstances and immediate danger, can require a departure from any Rule (2(b)). It is the answering Rule to the deliberate gaps mapped in Chapter 9. See: Ch 10 (good seamanship), Ch 6 (savings clauses and the force of “exonerate”).
Rule 3: General Definitions · TIER 2
Rule 3 defines the terms the rest of the instrument runs on, and Chapter 7 reads them for their traps. The ones that catch officers: a vessel not under command is disabled through “some exceptional circumstance” (mechanical failure qualifies; being undermanned does not); a vessel restricted in her ability to manoeuvre is restricted “from the nature of her work,” so the status comes from the activity, not the ship; underway means only not at anchor, not made fast, not aground, so a vessel stopped and drifting is still underway; in sight means observed visually only, which is what decides whether Section II or Rule 19 governs; and a vessel constrained by her draught is, by definition, a power-driven vessel, so a normal crossing can develop with her.
See: Ch 7 (the words and their consequences), Ch 5 (Rule 3 as the first check before the conduct Rules).