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COLREG

Rule 16: Action by Give-way Vessel

If you are directed to keep out of the way, take early, substantial action to keep well clear.

You · A
Decision 1 of 3

You are in A. B, a power-driven vessel, is on your starboard side with risk of collision. Who must keep out of the way?

How it applies

  1. WhoEvery vessel directed to keep out of the way: crossing, overtaking or meeting a Rule 18 vessel.
  2. What it asksTake early and substantial action to keep well clear of the other.
  3. HowA change of course and/or speed large enough to be readily apparent to the other by eye or on radar (Rule 8(b)).
    1. Avoid a succession of small alterations.
    2. With enough sea room, an alteration of course alone is often the most effective (Rule 8(c)).
    3. Slackening speed, stopping or reversing also works when more time is needed (Rule 8(e)).
After an illustrative avoiding manoeuvre, give-way vessel A passes astern of B. Early and substantial action helps keep well clear. This unscaled scene prescribes no universal turn angle and does not prove a numerical passing distance.

The full version

Practise Rule 16 in the Academy

Free: a preview of this unit with its key points. The whole unit is in the Exam Pass, once for 12 months.

What the Exam Pass adds

  • The interactive model: move the other vessel and watch the give-way vessel's large, early action.
  • Four new sketched cases: how much to change, no room, overtaking and who it speaks to.
  • The Rules 15 to 17 path, with your progress saved.
Preview Rule 16 in the Academy

Practise with the free test 40 questions with explained answers · no sign-up

Before you apply Rule 16

Rule 16 says how the give-way vessel acts; other rules decide who she is. In these cases another rule governs, or adds to it:

  • You are the stand-on vesselNot your rule: keep your course and speed (Rule 17).
  • Restricted visibility and not in sightRule 19 applies: action must still be substantial and in good time, but there is no give-way vessel.
  • In a traffic separation schemeRule 16 still applies and Rule 10 adds to it: do not impede vessels following a traffic lane.

Frequent mistakes

  • Wrong: "A tiny late alteration is enough."

    Right: COLREG requires early and substantial action, not a token last-minute move.

  • Wrong: "I can cross ahead if I eventually clear the other vessel."

    Right: Your action must keep you well clear; merely getting past is not the test.

  • Wrong: "I can wait until the other vessel reacts."

    Right: The vessel directed to keep out of the way must take the action.

More detail for the exam

The rule in plain words

When do you act?
If you are directed to keep out of the way, do not wait: act as early as possible.
How substantial must it be?
A token alteration is not enough: take substantial action, not a hesitant gesture.
What is the aim?
Your action must leave the other vessel clearly separated: keep well clear of her.

Exam keys

  1. Spot both qualifiers: "early" and "substantial"; missing either changes the answer.
  2. "Keep well clear" is the result being tested, not merely making an alteration.
  3. "So far as possible" qualifies the action; it does not erase the give-way duty.

How to read it

Read Rule 16 as a three-part test: early action, substantial action, and a result that keeps you well clear.

"So far as possible" asks for the strongest practicable action; it is not permission to delay.

Key points

  • Give-way duty → act.
  • Early · substantial · well clear.
  • Early means before the situation tightens.
  • Action must achieve clear separation from the other vessel.

This rule's practice test is free in full, with no sign-up. The 10-question free limit applies to quizzes and mock exams.

Official text

IMO COLREG 1972 U.S. Coast Guard — International Navigation Rules (2024)

Full wording of the rule, reproduced from the official source below.

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.
Source:

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Reviewed by Ramon Curto, Nautical teacher at IECNPC · Last reviewed:

Frequently asked questions about COLREG Rule 16

What must the give-way vessel do under COLREG Rule 16?

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.

How early must the give-way vessel act?

Early — not at the last moment. The action must be early, substantial and effective: clearly visible to the other vessel and resulting in a safe passing distance, so that the goal is to keep well clear rather than to barely avoid collision.

Why are small course changes a problem for the give-way vessel?

Because the action has to be substantial and readily apparent to the other vessel. Making small course changes the other vessel cannot notice, and acting only once the vessels are already close, are the usual Rule 16 failures.