Report on carbon monoxide poisoning of two friends in York – learn the lessons from this repeated story

The Boat Safety Scheme (BSS) is asking boaters to learn the lessons when, for the second time in six years, two inland boaters have died in a craft having equipment DIY installed with improvised, unsuitable exhaust systems and no working carbon monoxide (CO) alarms, according to the Marine Accident Investigation Branch report published today on the vessel Diversion, on which two friends died in York on 4 December 2019.

The events of Easter 2013 on Lake Windermere that saw a mother and daughter die on a sports cruiser when exhaust fumes from DIY exhaust filled the cabin space were sadly repeated on Diversion. The wrong-sized automotive silencer was fitted to the diesel-fuelled heater and then was wrapped in exhaust foil hiding the problem until the MAIB investigation revealed the cause and the source of the highly toxic gas.

The report shows that lethal amounts of toxic CO were being pumped into the cabin as the leak in the exhaust was only a few millimetres away from the circulatory warm air intake on the heater and all this was happening without warning, as a CO alarm had been removed.

The BSS urges boater owners to look after themselves and their fellow crew members by ensuring that any appliances and systems used on the boat are installed safely by competent fitters, then run according to the instructions, and kept in good condition with routine professional maintenance.

The BSS manager, Kevin Tyson, wishes to remind boaters of the following:

‘The last line of defence against either CO from equipment on your boat or CO caused by sources beyond your boat is a suitable working CO alarm which is compulsory for boats with cabins on most inland waterways.’


You can read more about what you need to do to protect yourself and your crew from the risk of being poisoned by CO on the BSS website at

If you would like to read the full MAIB reports on both the sports cruiser Arniston and the recent report on the Diversion vessel they are provided below:

Arniston report:

Diversion report:

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