Rule 16 — What the Give-way Vessel Must Actually Do

What the rule requires

Rule 16 is a single sentence: every vessel which is directed to keep out of the way of another vessel shall, so far as possible, take early and substantial action to keep well clear 33 CFR §83.16. Five phrases in that sentence carry the whole rule, and every question on this topic turns on one of them.

"Directed to keep out of the way" is the trigger. Rule 16 does not designate anybody — it states the duty owed by a vessel that has already been named give-way by another of the steering and sailing rules. A candidate who cannot say why he is the give-way vessel in a given scenario cannot apply Rule 16 to it, because the rule attaches only once that designation exists.

"Every vessel" sets the scope, and it is as wide as it sounds. There is no tonnage threshold in the rule, no length threshold, and no restriction to power-driven vessels. Whatever the vessel's class, if she is the one directed to keep clear, this is her rule.

"Early" is the timing test. The action is owed while the situation can still be resolved with room to spare, not at the point where the encounter has closed up.

"Substantial" is the magnitude test, and it is the half candidates drop. A change of course or speed that leaves the other vessel unable to see that you are keeping out of her way has not satisfied Rule 16, however correct its direction. This is why a plan of small successive adjustments as the range closes is a failing answer: each increment is neither early nor substantial, and the rule requires both at once.

"Keep well clear" is the standard the maneuver is judged against — the result, not the intention. You have complied when the passing distance you have produced is a well-clear passing distance.

"So far as possible" is the rule's only qualifier, and it does not create discretion about whether to act. It admits the case where full compliance is not possible; nothing in the rule specifies what those circumstances are, so treat any answer that leans on this phrase to excuse a late or token maneuver as wrong.

There is no number in this rule

Closed-book candidates arrive trained to hunt for values, and Rule 16 has none to give. No cable, no yards, no minimum CPA, no minimum degrees of alteration, no time limit. The rule states a standard of conduct and a standard of result . When an option offers a specific passing distance as the requirement of Rule 16, that specificity is the tell that it was written to be wrong.

The duty does not transfer

Once you are the give-way vessel, nothing the other vessel does moves the obligation off you. If she maneuvers because it has become apparent you are not taking appropriate action, your duty to keep out of the way is unchanged 33 CFR §83.17. Rule 17(d) says so in terms: the Rule does not relieve the give-way vessel of her obligation to keep out of the way.

International and Inland

Rule 16 is identical in both regimes. Inland Rule 16 is word-for-word the International rule COLREGs Rule 16, and the Inland text is codified at §83.16. Rule 17 is likewise identical word for word COLREGs Rule 17. A question on either rule labelled "(International Only)" or "(Inland Only)" has the same correct answer as one labelled "(Both International & Inland)" — there is no divergence here to hedge against, and hedging costs marks.

You are the give-way vessel. The other vessel, having seen no action from you, alters course to open the range. Are you now free to hold your course and speed?

No. Rule 17(d) states that Rule 17 does not relieve the give-way vessel of her obligation to keep out of the way. Her maneuver under 17(a)(ii) does not swap the roles or discharge your duty; you still owe early and substantial action to keep well clear. Answers built on the idea that the obligation shifts to whichever vessel moves first are wrong every time they appear.

Telling it apart — Rule 16 against Rule 17

The criterion that separates these two rules is which vessel a steering and sailing rule has directed to keep out of the way. That one fact assigns the roles; everything else follows.

Give-way vessel — she is the vessel directed to keep out of the way. Her duty is one duty: early and substantial action to keep well clear, so far as possible 33 CFR §83.16. Rule 16 gives her no permissive clause, no option to stand on, and no trigger condition to wait for. Most often misfiled by candidates who read the scenario, find themselves in the more privileged-sounding position, and answer "maintain course and speed."

Stand-on vessel — she is the other vessel, and her duty is to keep her course and speed COLREGs Rule 17(a). She may take action to avoid collision by her maneuver alone as soon as it becomes apparent that the give-way vessel is not taking appropriate action in compliance with the Rules. That is permission, on a trigger, not an instruction.

Stand-on vessel in extremis — when, from any cause, she finds herself so close that collision cannot be avoided by the action of the give-way vessel alone, she shall take such action as will best aid to avoid collision COLREGs Rule 17(b). Note the change of verb: 17(a)(ii) is may, 17(b) is shall. Questions are written on exactly that difference.

Stand-on vessel, power-driven, crossing — a power-driven vessel taking action under 17(a)(ii) to avoid collision with another power-driven vessel shall, if the circumstances of the case admit, not alter course to port for a vessel on her own port side 33 CFR §83.17. This restriction sits in Rule 17, on the stand-on vessel, in the crossing case only. Candidates routinely attach it to the give-way vessel and to every situation, and it belongs to neither.

The asymmetry is the point worth carrying: Rule 16 is one obligation with no conditions, and Rule 17 is a set of obligations and permissions that switch on and off with the other vessel's behaviour and the closing range.

You are the stand-on vessel, power-driven, in a crossing situation with another power-driven vessel on your port side. She is not acting. You decide to maneuver. Which alteration does Rule 17 restrict?

If the circumstances of the case admit, you shall not alter course to port for a vessel on your own port side . The restriction applies to a power-driven vessel acting under 17(a)(ii) against another power-driven vessel in a crossing situation. It is not a general prohibition on port alterations, and it is not addressed to the give-way vessel.

Working a question

A question that puts you aboard the give-way vessel is answered by testing each option against the phrases of Rule 16 in a fixed order. Take the concrete case: you are the give-way vessel to a vessel five miles off, her bearing steady and the range closing.

Confirm the designation. Some rule has to have named you give-way before Rule 16 says anything to you. If the scenario does not establish that, the question is about a different rule.
Test timing. With the range at five miles you are in the "early" window. An option that has you continue as before and reassess at one mile fails on early, whatever it has you do at one mile.
Test magnitude. An option offering a small alteration or a slight speed reduction fails on substantial. Same for an option that spreads the change over several small steps as the range comes down.
Test the result. Ask what passing distance the described action produces. If it merely reduces the risk rather than producing a well-clear passing, it does not meet keep well clear.
Check for a specific value. An option that states a required distance, CPA or number of degrees is importing a figure Rule 16 does not contain.
Check for role reversal. An option that has you maintain course and speed, or that has your duty end when the other vessel maneuvers, is defeated by 17(d) 33 CFR §83.17.

One option normally survives all six, and it will be the one phrased in the rule's own terms: act now, act big, pass well clear.

Where candidates lose the point

Reading yourself into the stand-on role. The scenario says another vessel is somewhere off your bow, the candidate pictures himself holding his line, and "maintain course and speed" looks like the disciplined answer. Keeping course and speed is the duty of the vessel the other one must keep clear of COLREGs Rule 17(a). If you are directed to keep out of the way, that option is not available to you at all.

Choosing the option with a number in it. Under time pressure a specific figure reads as the technical answer while "early and substantial action to keep well clear" reads as vague. It is the other way round: the phrase is the legal standard, and the figure is not in Rule 16.

Treating the give-way duty as extinguished by the other vessel's maneuver. This one attracts candidates who reason that if the stand-on vessel has taken the situation in hand, the give-way vessel would only confuse matters by acting. Rule 17(d) closes it: the give-way vessel's obligation to keep out of the way survives 33 CFR §83.17.

Answering with a whistle signal. Rule 16 requires action to keep well clear, and an option consisting only of sounding a signal has produced no alteration of course or speed and no increase in passing distance.

Using "so far as possible" as an escape. Candidates who remember that clause sometimes pick the option that waits, on the theory that the rule allows for circumstances. The qualifier does not license delay.

Hedging on the International/Inland label. Both regimes read the same on Rules 16 and 17 COLREGs Rule 16, so a "(Inland Only)" label on this material changes nothing about the answer.

Check yourself

You are the give-way vessel, the other vessel is four miles off with a steady bearing, and you come 5° to starboard, intending further small adjustments as the range closes. Have you complied with Rule 16?

No. Rule 16 requires action that is both early and substantial 33 CFR §83.16. A 5° alteration held while you wait to see what develops is not substantial, and a plan of successive small adjustments never becomes substantial at any point. The compliant action is a change large enough to produce a well-clear passing from the outset.

What minimum passing distance does Rule 16 require the give-way vessel to achieve?

The rule states none. The requirement is to keep well clear, which is a standard of result rather than a figure . Any answer choice quoting a distance, a CPA or a number of degrees is not stating Rule 16.

(Both International & Inland) Which vessels does Rule 16 apply to?

Every vessel which is directed to keep out of the way of another vessel . No class of vessel, length or tonnage is exempted by the rule, and it is worded identically under International and Inland COLREGs Rule 16.

You are the stand-on vessel. The give-way vessel has plainly done nothing and the range is closing. Under Rule 17, are you required to maneuver at this point, or permitted to?

Permitted. As soon as it becomes apparent that the give-way vessel is not taking appropriate action in compliance with the Rules, you may take action to avoid collision by your maneuver alone COLREGs Rule 17(a). The requirement arrives later: when you are so close that collision cannot be avoided by the give-way vessel's action alone, you shall take such action as will best aid to avoid collision COLREGs Rule 17(b).

You are the give-way vessel. You have taken a substantial alteration and the other vessel has also altered. Which vessel now owes the duty to keep out of the way?

You still do. Rule 17 does not relieve the give-way vessel of her obligation to keep out of the way 33 CFR §83.17. The duty is not shared out, traded or discharged by the other vessel's action; it ends when the vessels are clear.

An option reads: "As the give-way vessel, sound one short blast and maintain course and speed." Why is it wrong on Rule 16 alone?

Two of its elements fail. Maintaining course and speed is the stand-on vessel's duty, not yours , and a signal by itself is not action to keep well clear as Rule 16 requires .

A question is labelled "(International Only)" and asks what action a vessel directed to keep out of the way must take. Does the Inland answer differ?

No. Inland Rule 16 is word-for-word identical to the International rule , and it appears in the Inland regulations at §83.16. Answer it the same way under either label.