COLREGs trainerPart B: Steering and Sailing Rules
Rule 6
Proceed at a speed allowing proper and effective action to avoid collision.
Wording follows the International Regulations as printed in the US Coast Guard Navigation Rules handbook (2024), with British spelling, and is shortened in places. Download the rules
Every vessel shall at all times proceed at a safe speed so that she can take proper and effective action to avoid collision and be stopped within a distance appropriate to the prevailing circumstances and conditions. In determining a safe speed the following factors shall be among those taken into account:
(i) the state of visibility; (ii) the traffic density, including concentrations of fishing or other vessels; (iii) the manoeuvrability of the vessel, especially stopping distance and turning ability in the prevailing conditions; (iv) at night, the presence of background light such as shore lights or back-scatter from her own lights; (v) the state of wind, sea and current, and the proximity of navigational hazards; (vi) the draught in relation to the available depth of water.
(i) the characteristics, efficiency and limitations of the radar equipment; (ii) any constraints imposed by the radar range scale in use; (iii) the effect on radar detection of sea state, weather and other sources of interference; (iv) that small vessels, ice and other floating objects may not be detected at an adequate range; (v) the number, location and movement of vessels detected by radar; (vi) the more exact assessment of visibility possible when radar is used to determine range.
A training aid, not the official text. The COLREGs are an IMO convention, and your national authority publishes the version that applies in its waters. Check the rules themselves before you rely on them at sea. Download the rules.