The Marine Accident Investigation Branch (MAIB) have this month issued a safety bulletin highlighting the importance of installing carbon monoxide (CO) alarms on boats with enclosed accommodation spaces.

The warning follows the loss of two lives from CO poisoning on-board the motor cruiser, Diversion, moored on the River Ouse in York, on 4 December 2019. The subsequent on-going investigation has so far found that the diesel-fuelled heater had been leaking exhaust fumes into the boat’s cabin whilst the two men were ashore, consequently both men were overcome by a high level of CO gas and died shortly after they returned to the boat’s cabin.

The MAIB has ascertained that no CO alarm was fitted on the vessel and that the cabin heater had been installed by the vessel’s owner, the installation had not been professionally checked and no servicing had been carried out. Findings from the investigation will be published by the MAIB in a full investigation report.

CO is a silent killer, therefore, it is essential that CO alarms are fitted in areas where it could accumulate. 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.

The symptoms of CO poisoning are similar to flu or food poisoning, and include headaches, tiredness, nausea and dizziness. The greater the amount of CO the more severe the symptoms will get, leading to weakness, loss of balance and memory. High levels can also cause collapse, unconsciousness and death.

Andrew Moll, Chief Inspector of Marine Accidents at the MAIB, commented: “The MAIB investigation into this tragic loss of lives once again highlights the importance of installing carbon monoxide alarms on boats with enclosed accommodation spaces. 

“This is the fifth fatal marine accident investigated since 2014, where a functioning carbon monoxide alarm could have saved lives. Carbon monoxide alarms suitable for the marine environment are readily available, inexpensive and simple to fit, and I urge boat owners to invest in one as soon as possible.” 

For more information on how to avoid a CO related incident, visit the advice page on the RYA Safety hub. 

You can find further information on CO alarms for boats here.