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A guide to carbon monoxide safety on boats

Statistics from the charity CO-Gas Safety show that each year, 40 people in the UK die and a further 300 are injured through unintentional carbon monoxide (CO) poisoning. 28 CO accidental deaths in the decade up to 31 August 2005 were on boats, and the charity suggests that many other cases of CO poisoning go unreported.

As The Canal & River Trust reminds us as part of their Boat Safety Scheme, the very fact that boats are designed and built to keep water out also means they can be very effective floating containers for harmful gases and fumes.

Keeping yourself, your crew and passengers ‘CO safe’ involves understanding the risks, keeping your boat and on board appliances properly maintained and following essential good housekeeping rules.

Carbon monoxide: understanding the risks

CO is colourless, odourless, tasteless and poisonous and is produced when carbon-based fuels fail to burn properly.

The early symptoms of CO poisoning can mimic many common ailments, which is one of the reasons why it’s thought that many cases of CO poisoning go undetected. These symptoms can include tiredness, headaches or dizziness, nausea, pains in the chest and stomach, confusion, visual problems and loss of consciousness. When CO concentrations are high, CO can kill without warning.

In the cabin of a boat, harmful CO levels can arise as a result of defective or poorly maintained galley and other appliances, faulty solid fuel stoves (especially broken flues causing gases to escape), exhaust fumes from the boat engine and blocked ventilation.

Recognise potential danger signs on your boat

You should regularly check fuel-burning appliances and engines for signs that CO could be escaping from them. These signs include the following:

  • Discolouration, sooty smears or yellow/brown staining on an appliance or the flue
  • Appliances burning yellow or orange rather than blue flames
  • Appliance flames failing to light or burning a weak flame
  • Pilot lights frequently blowing out
  • Smelling or seeing smoke or exhaust fumes or smoke in the cabin
  • Increased condensation in the cabin

If you notice a problem, get a suitably qualified technician to locate the source and fix the engine or appliance before using it.

Preventing CO build-up in your boat

  • Only install and use appliances that are certified for use on boats.
  • Fuel-burning appliances should be installed in line with manufacturers’ instructions. Heating appliances should be installed by fully qualified engineers with specific experience in marine installations.
  • Only use appliances as per the instructions. In particular, do not use onboard cookers for heating purposes.
  • Make sure appliances are serviced regularly in accordance with the manufacturers’ instructions. Stove chimneys should be swept at least once a year.
  • Do not block vents and flue terminals. Where those terminals are positioned on cabin tops, ensure that they are not restricted by stowed items, ropes and tarpaulins.
  • Regularly check flue pipes for rusting, cracks, blockages and loose or missing connections.
  • Listen for changes in the way the engine sounds as this could be an indication of an exhaust component failure.
  • At least once a month, check to ensure exhaust clamps are securely in place. Look for signs of possible exhaust leaking, including rust or black streaking, water weaks and corroded or split fittings.
  • Annual engine servicing by a qualified marine technician is an important safeguard against carbon monoxide problems. This ensures engines and generators are properly tuned and maintained. A proper inspection should also ensure all exhaust components are checked for cracking, leaking and loosening.

Carbon monoxide alarms

All cabins that feature a fuel burning appliance should have a BS EN 50291-2 certified CO alarm fitted. For a single-use cabin, a single alarm is sufficient. Where fuel burning appliances, engines or generators are used will people onboard are sleeping, separate alarms are required for all sleeping quarters.

Follow manufacturers’ installation instructions for alarms. In particular, do not place the alarm directly above a heat source and do not attempt to replace the battery. Each time you go on a boat trip, press the test button to test the operation of each CO alarm as part of your essential pre-trip checks.

Remember, however, that alarms provide a fallback warning system: they are not a substitute for following good CO safety practice.

Following carbon monoxide safety guidelines is a vital element of safe boating. To take to the water with confidence and with the level of cover that meets your specific requirements, explore our boat insurance options today.