Carbon Monoxide - the silent killer

QuietKiller
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Once, on a long leg crossing the Pacific, our engine failed and during an almost windless, sunless few days we resorted to the use of a mobile diesel generator for power generation. We thought placing it under the dodger so that it couldn't get wet when it rained was a great idea until we realised that it was pumping carbon monoxide straight into the saloon!

Here, the RYA's Cruising Manager, Stuart Carruthers, reminds us of the need to be aware of the dangers of carbon monoxide poisoning onboard:


You cannot see feel, smell or taste carbon monoxide (CO), but it is highly poisonous. Carbon monoxide poisoning is the most common type of fatal air poisoning in many countries which is why it is often called the silent killer.
CO in excessive quantities is produced by incomplete burning of carbon-based fuels, including gas, oil, wood and coal. When CO enters the body, it replaces the oxygen in the bloodstream and prevents the blood from bringing oxygen to the heart, brain, body tissues, and organs.

According to the Health and Safety Executive (HSE) statistics about 15 people a year die from CO poisoning caused by faulty gas appliances and flues that have not been properly installed, maintained or that are poorly ventilated.
Levels that do not kill can cause serious harm to health if breathed in over a long period. In extreme cases paralysis and brain damage can be caused as a result of prolonged exposure to CO. Increasing public understanding of the risks of CO poisoning and taking sensible precautions could dramatically reduce this risk.

Recognise the signs of CO poisoning:
Common symptoms include headache tiredness and being sick. The greater the amount of CO the more severe the symptoms will get leading to weakness, loss of balance and memory. Extreme levels may well cause collapse, unconsciousness and death.

Know the danger signs on your boat:
There are signs that you can look out for which indicate incomplete combustion is occurring and may result in the production of CO;
Burners with yellow or orange rather than blue flames
Soot or yellow/brown staining around or on appliances or its flue
Pilot lights that frequently go out
Appliances that are difficult to light and keep lit
Increased condensation inside windows
Smell of exhaust fumes inside the cockpit or cabin

Flue gases from solid fuel stoves, more common to canal boats, can have up to 100 times the concentrations of CO found in gas burners. Smouldering embers and charcoal give off particularly high levels of CO so never bring a cooling barbeque into an enclosed space for any residual warmth.

How to prevent the build-up of CO on your boat:
It goes without saying that any appliance that burns carbon based fuels should be properly installed and serviced by someone who is competent. They will be able to ensure that there is an adequate air supply to run the appliance and that flues are properly installed where they are fitted.

It is also worth buying an audible CO alarm that will immediately alert you to any carbon monoxide in your boat.