Over the last 10 years, nine deaths caused by the invisible and odourless gas have been recorded by the UK’s Marine Accident Investigation Branch.
A safety message was issued by the UK government recently after an incident last year in which the build-up of exhaust gas in the cabin of a sports cruiser led to the deaths of two men.
There was no carbon monoxide detector on board.
Guernsey Coastguard is running its own safety campaign, letting boat owners know what they can do to keep themselves and others safe.
Assistant harbour master James Way said the gas was a silent killer and boats often had many sources, including engines, cookers, heaters and exhaust fumes.
‘When you breathe in carbon monoxide, it replaces the oxygen in your blood stream, preventing essential supplies to your heart, brain and other vital organs,’ he said.
‘This makes it essential that carbon monoxide alarms are installed and properly maintained in areas where carbon monoxide can accumulate and pose a risk to health, such as the cabins and cockpits of motor cruisers.’
Guernsey Boatowners’ Association president Nick Guillemette said he fitted a combined CO and smoke detector in his 10m Cygnus, Cyfish, several years ago.
‘We always tell people if they ask to make sure that they have one fitted and that it’s fitted in the right place’ he said.
Owners were also advised to fit a fire suppression system and also to make sure that the safety systems were up to date by having them checked regularly.
Cooking gas was another problem, he said. ‘At least 50% of the boats in the marina have gas installations of some kind and they need to be checked on a regular basis, and the hoses, which are date-stamped.’
Mr Way said that boat users needed to ensure that all spaces were well-ventilated and that exhausts were clear of obstructions.
‘You should never ignore the smell of exhaust fumes in any enclosed space,’ he said.
. Full safety guidance is harbours.gg/carbon-monoxide.