Covers could have been a covert killer

Recently a Lake Macquarie man learnt of the real dangers posed by carbon monoxide poisoning from exhaust gases.


On a cold and wet weekday a Lake Macquarie man had gone down to his 8 metre cabin cruiser that was on a swing mooring to get it ready for the Easter break. He suspected the battery charge may have been low so he brought out a jumper pack.

He boarded his vessel and since it was a cold and rainy day he only opened the centre flap of the boat’s storm covers, he also left the cabin windows and the forward hatch shut.

He attempted to start the boat’s petrol inboard engine to see if it would start under its own battery power. To avoid putting excess load on the battery he did not run the bilge blower that was fitted. To his surprise it started without having to use the jumper pack so he decided to keep it idling to charge the battery, forgetting then, to turn the bilge blower on.

About an hour and a half after the boat was started, a man who was working on the neighbouring boat became concerned at the length of the time the cruiser’s engine was running and rowed over in his dinghy to check if everything was alright. He found the owner of the cabin cruiser unconscious and slumped over the helm of the vessel. He started cardiopulmonary resuscitation (CPR) and with the help of a nearby boater got him to an ambulance. The victim was taken to hospital and was released from hospital the following day with no identified health damage.

However if it was not for the neighbouring boat owner checking on his welfare he would have succumbed to the gas and died.

The exhaust gases accumulated in the cabin because the vessel was pointing into the wind. This creates what is called ‘backdrafting’ or the ‘station wagon effect’. The wind blowing around the sides of the vessel creates a higher air pressure outside the cabin than inside the cabin. The exhaust gases are then sucked into the enclosed cabin as the pressures attempt to equalize.

Occupants are usually unaware of the carbon monoxide presence as it is both odourless and colourless.

To avoid the station wagon effect, boat operators need to ensure a free flow of air throughout the length of the boat. This can be achieved by opening the fore hatch or windows and opening the side covers.

Lessons learned

  1. Always be aware of the danger of carbon monoxide present in exhaust gases from engines. It is colourless and odourless
  2. Ensure the cabin or cockpit area of any vessel is well ventilated by opening all windows and hatches and rolling up all cockpit covers when running motors
  3. Utilise all equipment available to assist ventilation such as bilge blowers
  4. Familiarise yourself with safety information on carbon monoxide poisoning.
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