Part B · Section I

COLREGs Rule 6: Safe speed

Rule 6 says every vessel must always go at a safe speed: one that lets it take proper and effective action to avoid a collision and stop within a distance suitable for the conditions.

What Rule 6 says

  1. Factors for every vessel: visibility, traffic density (including fishing fleets), your manoeuvrability and stopping distance, background lights at night, the state of wind, sea and current, nearby hazards, and your draught compared with the depth of water.
  2. Extra factors with radar: its range and limitations, the range scale in use, sea state and weather clutter, small vessels and ice it may not detect, how many vessels it is tracking, and the more exact assessment of visibility it allows.

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

There is no speed number. In fog or a busy harbour entrance, safe speed for a yacht may be a few knots so you can stop or turn in time; in open water and good visibility it may be everything you have.

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