The meaning of safe speed

Rule 6 – Safe Speed of the International Regulations for Preventing Collisions at Sea (COLRegs) states that every vessel shall at all times travel at a safe speed so that it can take action to avoid a collision and be stopped with a distance appropriate to the prevailing circumstances and conditions.

 In determining safe speed the following factors shall be among those taken into account:

  • State of visibility. Drive slowly in fog, rain, mist, smoke or glare.
  • Traffic density including fishing or any other vessels. Slow down on busy waterways, when near moored vessels, larger vessels, work boats or operating in narrow channels.
  • Manoeuvrability of the vessel with special reference to stopping distance and turning ability in the prevailing conditions.
  • At night the presence of background lights such as shore lights or from back scatter of a vessel’s own lights restricts visibility.  Remember, at night many potential hazards may not be lit or may not be easily seen.
  • The state of wind, sea, current and proximity of navigation hazards.
  • The draft in relation to the available depth of water.
  • The characteristics, efficiencies and limitations of radar equipment.

What it means

Similar to vehicles boats are required to limit their speed in order to avoid a collision. Rule 6 tells us that you must constantly evaluate the prevailing conditions and circumstances. For example, a safe speed outside a fog area may be in excess of 10 knots. A safe speed in or on approach to fog may be only a few knots. Did you know that atmospheric visibility was excellent on the night the Titanic struck an iceberg?

Rule 6 describes a list of factors to be aware of (see above) but this cannot be considered as complete as it’s impossible to predict what other special circumstances may need to be taken into account. No one day on the water is the same. A safe speed is not necessarily a zero speed either. A vessel dead in the water has no steerage and therefore no ability to change course to avoid a collision.

The potential consequences for breaking Rule 6 are unimaginable.

This is clearly demonstrated in the incident on Sydney Harbour on the evening of 28 March 2007 when a Sydney Ferries vessel, the Pam Burridge and motor cruiser Merinda collided on Sydney Harbour, under the Harbour Bridge off Dawes Point. Of the 12 people on board the Merinda four died. Two others were seriously injured. Miraculously, although the vessel was torn in half and submerged within a couple minutes, the remaining passengers and crew of Merinda survived with minor injuries.

The Coroner’s Report highlights one of the issues contributing to this incident as being that the Pam Burridge was not travelling at a speed which allowed it to manoeuvre or stop to avoid the collision once the Merinda was sighted.

If you do not understand the rules and how they are applied in practice on the water do the right thing, get proper training from a professional maritime training organisation.


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