Part B · Section I

COLREGs Rule 8: Action to avoid collision

Rule 8 says any action to avoid a collision must be positive, made in ample time and large enough to be readily apparent to the other vessel, and you must check that it works until the other vessel is past and clear.

What Rule 8 says

  1. Action shall be taken in accordance with the steering rules and, if circumstances admit, be positive, made in ample time and with due regard to good seamanship.
  2. Alterations of course or speed should be large enough to be readily apparent visually or by radar. Avoid a succession of small alterations.
  3. In open water, an alteration of course alone may be the most effective action, if made in good time, substantial, and does not cause another close-quarters situation.
  4. Action should result in passing at a safe distance. Check its effectiveness until the other vessel is finally past and clear.
  5. If necessary, slow down or take all way off by stopping or reversing to gain time.
  6. A vessel required not to impede another must take early action to leave enough sea room, and still has that duty when risk of collision develops.

This is a plain-English summary, not the official wording. For the exact text, see the IMO convention. In UK waters the rules are given legal force by the Merchant Shipping (Distress Signals and Prevention of Collisions) Regulations.

What it means on a yacht

A 10° nudge is invisible from a ship's bridge. Turn boldly, 30° or more, or tack, so your change of heading is obvious. Then keep watching the bearing open.

Practise it

Test yourself on who gives way in the free COLREGs trainer, or print the rules of the road cheat sheets for the chart table.

Other rules in Part B