Chapter 10: Good Seamanship and the Ordinary Practice of Seamen
Every chapter so far has been building toward an admission the Rules make about themselves. For all their precision, the COLREGs cannot foresee every situation, and they know it. So they reach outside their own text to a standard they do not define and assume you already hold: the ordinary practice of seamen. Rule 2 is where that reach is made, and it is the most important rule in the instrument that tells you almost nothing on its face. To a first-time officer the phrase is a problem, because the Rules lean their whole weight on “the ordinary practice of seamen” and “good seamanship” without ever saying what those are. This chapter answers that first, because the rest of Rule 2 makes no sense until you know what it is pointing at.
What seamanship actually is
Start with the thing itself, before the law. Seamanship is the accumulated body of professional practice for handling and navigating a ship safely. It is not instinct, and it is emphatically not improvisation or feel. It is a real, learnable, shared body of knowledge, built up over centuries of men taking ships to sea and watching what worked and what cost ships and lives. It includes knowing how a ship behaves in shallow water, how she interacts with another vessel passing close aboard, how to anchor so that you hold and so that you do not foul another ship, how a current sets you down on a hazard, when the weather has made it unsafe to be where you are, and a thousand other things that have nothing to do with the right of way and everything to do with not losing the ship. It is a craft, and like any craft it has a standard. A competent, prudent mariner does these things to a recognised level, and that level is what the law has in mind when it speaks of the ordinary practice of seamen: the standard of care expected of a competent mariner, the body of accepted professional practice, experience and judgement that the Rules cannot exhaustively codify (Cockcroft & Lameijer, 7th ed, comment on Rule 2).
The crucial thing to understand is the relationship between this body of practice and the Rules. Seamanship came first. For centuries it was all there was, as Chapter 2 described, and the COLREGs were laid down on top of it, not in place of it. The Rules assume the whole of good seamanship underneath them, and then add a specific, agreed script for the one problem seamanship alone could not solve, which is making two strangers predictable to each other in an encounter. They never replace the underlying competence. This is why the Rules can be silent on so much. They take it as given that you can handle your ship, and they only legislate the part that needed international agreement. “The ordinary practice of seamen” is simply the legal name for that assumed competence, and “good seamanship” is doing it to the standard a court would expect of a reasonable and prudent mariner.
Cockcroft makes the content concrete with examples of what the ordinary practice of seamen actually demands, and they are worth seeing, because they show that this is specific professional knowledge and not a vague appeal to being sensible. A vessel underway is expected to keep clear of a vessel at anchor as a matter of seamanship. A vessel that anchors must do so without endangering others, not too close to other anchored vessels, with sufficient cable for the circumstances and a second anchor if needed. In dense fog a vessel without operational radar may not be justified in being underway at all, and should anchor if it is safe and practicable to do so. The effects of shallow water must be allowed for, including the squat that increases a fast vessel’s draught and the interaction that can sheer one ship toward another passing close aboard (Cockcroft & Lameijer, 7th ed, comment on Rule 2). None of that is in the steering and sailing rules. All of it is required of you, and Rule 2 is how.
Rule 2(a): compliance is the floor, not the ceiling
With the concept in hand, the rule reads cleanly. Rule 2(a) provides that nothing in the Rules shall exonerate any vessel, or her owner, master or crew, from the consequences of any neglect to comply with the 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 (MISCPUB 0127, Rule 2(a)). Read it in two halves. The first half says you are not excused for breaking the Rules. That much is obvious. The second half is the one that changes how you think: you are equally not excused for neglecting a precaution that good seamanship required, even where no specific rule compelled it. Obeying every applicable rule to the letter is therefore necessary but not sufficient. The Rules are a floor. If a competent mariner would have done more, the fact that the text did not spell out that “more” is no defence.
PRACTICAL NOTE: Good seamanship is a higher standard, not a lower one
Officers sometimes hear “the ordinary practice of seamen” as a soft, forgiving phrase, a bit of latitude. It is the opposite. Rule 2(a) uses it to raise the bar above the written Rules, not to lower it. It means a court can find you at fault for something no rule named, because a competent mariner would have seen it and acted. Good seamanship never gets you out of an obligation. It adds one.
This has real legal weight behind it, not just professional disapproval. Rule 2 provides the legal basis for action against a vessel’s owners and master, with any case tried in the courts of the country concerned, and on the high seas under the appropriate national shipping act (BR45 Vol 4, para 1013). For an RAN officer this connects straight back to Chapter 4. The warship’s compliance is mandated from within the service, but the standard of seamanship the rule imports is the same one the courts apply to everyone, and a well-found warship is held to the upper end of it.
Rule 2(b): when seamanship requires you to break a rule
The second limb is the one that surprises people, because it says that sometimes good seamanship requires you to depart from the Rules. Rule 2(b) provides that in construing and complying with the Rules, due regard shall be had to all dangers of navigation and collision, and to any special circumstances, including the limitations of the vessels involved, which may make a departure from the Rules necessary to avoid immediate danger (MISCPUB 0127, Rule 2(b)). There are situations where obeying a rule would put you into the very danger the Rules exist to prevent. The classic case is a head-on meeting where Rule 14 directs you to alter to starboard, but there is shallow water close to starboard, or a third vessel overtaking you on that side, so the ordered manoeuvre would cause a casualty (Cockcroft & Lameijer, 7th ed, comment on Rule 2). Rule 2(b) is what permits, and sometimes compels, the departure.
TRANSLATION
Rule 2(b) (MISCPUB 0127): “In construing and complying with these Rules due regard shall be had to all dangers of navigation and collision and to any special circumstances, including the limitations of the vessels involved, which may make a departure from these Rules necessary to avoid immediate danger.”
Plain reading: if following a rule would cause a collision or other danger, you may break it to avoid the danger.
What the legal wording does that the plain version can’t: it sets the threshold high and narrow. The licence is not “whenever a departure seems advantageous.” It is two conditions that must both hold, special circumstances and immediate danger, and the departure is bounded to what is needed to avoid that specific danger. The wording is built to stop an officer from using “seamanship” as cover for simply preferring a different manoeuvre.
That narrowness is the whole point, and it must be held firmly. Rule 2(b) does not give any vessel the right to act contrary to the Rules whenever it is thought advantageous. A departure is permitted only when there are special circumstances and there is immediate danger. Both conditions must apply, and the departure must be of such a nature as to avoid the danger that threatens (Cockcroft & Lameijer, 7th ed, comment on Rule 2). Outside that strict gate, a “departure for good reasons” is just a breach, and the burden of justifying any departure falls squarely on the vessel that made it.
Within the gate, though, the obligation reverses. When the conditions are met, departing is not merely allowed. It becomes the seamanlike thing to do, and a failure to depart is itself a fault. The principle is old, and was stated with unusual clarity in a nineteenth-century judgment that is still good law:
Tasmania–City of Corinth (Lord Herschell, 1890): “As soon then as it was, or ought, to a master of reasonable skill and prudence, to have been obvious that to keep his course would involve immediate danger, it was no longer the duty of the master of the Tasmania to adhere to the … Rule. He was not only justified in departing from it, but bound to do so, and to exercise his best judgement to avoid the danger which threatened.” (cited in Cockcroft & Lameijer, 7th ed, comment on Rule 2)
There is a neat consequence here that resolves an apparent paradox, and Chapter 1 flagged it. A departure made under Rule 2(b) is not really a breach of the Rules at all. The Rules themselves, through Rule 2, require it, so the officer who departs to avoid immediate danger is obeying the instrument, not defying it. The text anticipates its own exceptions and folds them back in.
Judgement bounded by law
Put the two limbs together and Rule 2 reveals what it really is: the rule that governs the relationship between the script and your own judgement. Rule 2(a) says the script is a floor, and good seamanship can demand more than it spells out. Rule 2(b) says that in tightly defined circumstances good seamanship can demand that you set a rule aside. Neither limb hands you freedom. The Rules bound your judgement. They do not replace it, and they do not surrender to it. What Rule 2 forbids above all is the use of “seamanship” as a licence to improvise, to depart from the predictable script because you have spotted something cleverer, which is exactly the failure Chapter 1 warned against. Good seamanship is the discipline of doing more than the Rules say when more is needed, and of stepping outside them only when staying inside would cause the harm they exist to prevent, while carrying the full burden of that choice.
This is also why the manufactured stand-on position, discussed in Chapter 8, is a Rule 2 matter at heart. A vessel that creates a situation by her own manoeuvre and then claims the privileged role the resulting geometry would hand her is not exercising judgement. She is trying to escape it. Rule 2 will not let her, because the ordinary practice of seamen does not include profiting from your own default.
Why this chapter and the tensions are one idea
This chapter is the partner of Chapter 9. There it is argued that the apparent tensions in the Rules are deliberate, each one a place where the drafters declined to prescribe a fixed answer and handed the decision to the mariner. Rule 2 is the rule that says what you are expected to do when they hand it to you. Those tensions are where the Rules give you judgement. Good seamanship is the standard that judgement is held to. The two together are the reason a watchkeeper who has only memorised the text fails at exactly the moments that matter, and the reason this guide spends so long on the why. The text can be learned in a fortnight. The judgement the text assumes is the work of a career, and Rule 2 is the rule that demands it.
A short worked case: the rule that would cause the collision
Take a power-driven vessel meeting another power-driven vessel close to end-on at night, risk of collision developing. Rule 14 is unambiguous: both alter to starboard and pass port to port. Now add a fact. Close on your own starboard side is a third vessel, overtaking you and not yet past and clear, so a bold alteration to starboard would put you across her bow. The ordered manoeuvre would trade a manageable head-on for an immediate collision with the overtaking ship. This is precisely the territory of Rule 2(b): the presence of the overtaking vessel is a special circumstance, the collision a starboard alteration would cause is an immediate danger, and both conditions are therefore met (Cockcroft & Lameijer, 7th ed, comment on Rule 2). You are permitted, and on the authority of Tasmania–City of Corinth you are bound, to depart from Rule 14, taking instead whatever action actually avoids the danger: a reduction of speed, a hold, or an alteration the other way once the geometry allows. Two things must stay clear in your mind as you do it. The departure is lawful only because both conditions are genuinely present, not because another manoeuvre looked better. And the burden of showing that they were present rests on you. That is good seamanship under Rule 2: not freedom from the Rules, but the judgement the Rules assume you brought aboard with you.
See also: Ch 1 (predictability, and why a departure to avoid danger is not really a departure), Ch 4 (the standard of seamanship a well-found warship is held to), Ch 8 (how situations develop, and the manufactured stand-on position), Ch 9 (the tensions in the rules as deliberate allocations of judgement, of which Rule 2 is the answering rule).