MAIB releases the report about two fatalities aboard the Arniston

The MAIB has published its report and findings about two fatalities aboard the Arniston. Photo credit: Dave Nelson
The MAIB has published its report and findings about two fatalities aboard the Arniston. Photo credit: Dave Nelson

The MAIB has published its report and findings on the investigation of the two fatalities due to carbon monoxide poisoning on board the Bayliner 285 named Arniston on Lake Windermere on 1 April 2013.

This tragic case, which could have easily been avoided, involved a mother and her daughter who were overcome by fumes from a portable generator, which had been installed in the engine bay. It had been modified by the addition of an exhaust which subsequently failed allowing the small sleeping area to fill with lethal carbon monoxide.

On Monday 1 April 2013, the emergency services attended the motor cruiser Arniston on Windermere, Cumbria, where mother and her daughter (Kelly Webster aged 36 and 10 year Lauren Thornton) had been found unconscious.

The two females were taken by air ambulance to Lancaster Royal Infirmary where they were pronounced deceased. A postmortem concluded that the cause of death was carbon monoxide poisoning.
The subsequent MAIB investigation identified that:
• The carbon monoxide poisoning had resulted from the inhalation of fumes emitted from a portable generator installed in the boat’s engine bay.
• The external exhaust system fitted to the portable generator had been modified to incorporate a silencer that had become detached from both the generator and the outlet pipe to the vessel’s side.
• The portable generator’s engine exhaust fumes filled the engine bay and spread through gaps in an internal bulkhead into the aft cabin where the mother and daughter were asleep.
• The portable generator was not intended by its manufacturer to be installed into an enclosed space, nor was it intended to be modified in any way.
• The improvised exhaust system attached to the generator was constructed from materials and using methods that were not appropriate for this application.
• The boat’s occupants were not alerted to the danger because two carbon monoxide sensors fitted to the boat at build were out of date and had been disconnected from the power supply.

Click to read the MAIB report on the Arniston in full.

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