The US National Transportation Safety Board (NTSB) has issued the final report for its investigation of a 2023 fire aboard a passenger vessel last year in Alaska.
On January 19, 2023, the small passenger vessel Qualifier 105 was being stored ashore for the winter in the Northern Enterprises Boat Yard in Homer, Alaska when a fire started in a stateroom below the main deck. The local fire department extinguished the fire and no pollution or injuries were reported.
The vessel was used for marine survey, oceanographic research, environmental clean-up, housing, and private charters. The owners declared the vessel a loss of US$1.2 million.
While welders were on board performing aluminium hot work before the fire, investigators ruled out the hot work as a source of the fire, as there were no signs of a fire after or while conducting the work. Investigators concluded the fire was caused by an undetermined electrical source that ignited a stateroom ceiling.
The substantial use of combustible materials for stateroom ceilings and bulkheads throughout the vessel’s accommodation spaces contributed to the extent of the fire damage, the NTSB said. Although investigators could not definitively determine that stray welding current caused the fire, the NTSB report highlighted precautions to take for stray welding current.
“Stray welding current is a fault condition in which current goes through unintended conductors and back to the return terminal of a welding machine; it can cause fires by overheating wires,” the report said. “To avoid potential fires caused from stray welding current, maintenance personnel, owners, and operators should follow industry practice to place the work clamp (the return current clamp) of the welding machine as close as possible to the point of welding.”
Marine Investigation Report 24-15 is available online here.