Club Marine eNews

Carbon monoxide - the silent killer

CO risk on boats
Carbon monoxide can’t be seen, smelled or tasted – we outline a few simple measures that can help minimise the risk of exposure to this silent killer aboard boats.

CO has approximately the same density as air and flows freely through and into spaces. Because no appliance completely combusts its fuel, CO is produced whenever a material that contains carbon is burned.

Exposure to CO limits the ability of the bloodstream to carry oxygen. Symptoms include headaches, drowsiness, nausea, vomiting, irritated eyes and collapse. Unfortunately, these symptoms can be mistaken for the effects of seasickness, fatigue, sun exposure and alcohol.

Exposure to CO can prove fatal. Dangers can arise both from a high dose over a short period of time, or exposure to low doses over a prolonged period.
CO station wagon effect
Occupants of boats are at risk because of the presence of engines, generators, stoves and heaters and because of the enclosed and confined spaces found on vessels. In particular, fumes can build up in a boat’s cockpit if it is enclosed by windscreens and canopies.

The ‘station wagon’ effect (image, right) can draw in exhaust from behind the vessel when operating at slow speeds, too.

There’s a lot boaters can do to avoid CO accumulating on their boat, including:

  • Having engines and other appliances regularly checked by a qualified marine service centre
  • Always use gas appliances as per manufacturer instructions
  • Ensuring thorough ventilationCO risk raft-up
  • Ensure all fuel-burning engines and appliances on the boat are properly installed and maintained, and specifically request engine and exhaust systems be inspected at service time
  • Avoid using stoves and heaters in confined, poorly ventilated spaces
  • Never block or restrict exhaust outlets as this can lead to a build-up of gas, including CO
  • If travelling slowly or with a following breeze, ensure an adequate airflow through the vessel to avoid the station wagon effect
  • Be aware of the danger when rafted-up with other vessels – the cumulative effect of several vessels’ generators working in a confined area may increase risk significantly
  • Avoid using your boat’s engines and generators while moored, and ensure thorough ventilation if using them can’t be avoided
  • Never allow swimming or water play close to engine and generator exhaust vents, and watch children carefully if they are on rear decks or swimplatforms.
CO risk while swimming
Additionally, it’s recommended to have CO alarms installed in sleeping areas and near helm positions, and having them regularly inspected – keep in mind that CO detectors designed for homes may not be suitable for boats, where design and construction are very different.

And finally, educate your guests on carbon monoxide poisoning symptoms and risks so they know what to look out for.

You’ll find more information in Doug King’s Waterwise feature in the 35.1 Feb/March Club Marine Magazine, and on the Maritime Safety Victoria website at: