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Part B — Steering & SailingFoundation
6

Safe speed

In plain language

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.

Full text of Rule 6

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:

(a)

By all vessels:

(a)(i)

the state of visibility;

(a)(ii)

the traffic density including concentrations of fishing vessels or any other vessels;

(a)(iii)

the manoeuvrability of the vessel with special reference to stopping distance and turning ability in the prevailing conditions;

(a)(iv)

at night the presence of background light such as from shore lights or from back scatter of her own lights;

(a)(v)

the state of wind, sea and current, and the proximity of navigational hazards;

(a)(vi)

the draught in relation to the available depth of water.

(b)

Additionally, by vessels with operational radar:

(b)(i)

the characteristics, efficiency and limitations of the radar equipment;

(b)(ii)

any constraints imposed by the radar range scale in use;

(b)(iii)

the effect on radar detection of the sea state, weather and other sources of interference;

(b)(iv)

the possibility that small vessels, ice and other floating objects may not be detected by radar at an adequate range;

(b)(v)

the number, location and movement of vessels detected by radar;

(b)(vi)

the more exact assessment of the visibility that may be possible when radar is used to determine the range of vessels or other objects in the vicinity.

Reproduced from the COLREGs 1972 (as amended) for study. Always verify against the official IMO publication.

Key points

  • 1

    Visibility, traffic density, manoeuvrability, background lights, sea state and draught all matter.

  • 2

    With radar: account for its limitations and the range at which targets are detected.

  • 3

    Safe speed is a judgement — there is no single number on the dial.

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