The US National Transportation Safety Board has said that a fire that destroyed a small passenger / research vessel in Homer, Alaska last year was probably caused by an electrical fault was probably the cause.
Although there had been “hot work inside the vessel before the blaze, the NTSB ruled out this common fire hazard.
The fire broke out at noon on January 19th 2023, in a stateroom aboard the 30-metre passenger vessel Qualifier 105, which was being stored on shore at a yard in Homer, Alaska. Local firefighters responded and put out the fire. While there were no injuries or pollution reported, extensive internal damage forced the owners to declare the vessel a total loss. The cost came to an estimated $1.2m.
Qualifier 105 was a 1970-built aluminium-hulled Subchapter T boat, used commercially for research work and private charters. The NTSB has been taking a close look at this type of vessel ever since the aging “T-boat” Conception caught fire in 2019, killing all of the 33 people who were below deck at the time.
During Q3 2022 the boat was put on blocks in the Northern Enterprises Boat Yard in Homer. There were no known issues with the vessel’s mechanical or electrical systems, the owners told the NTSB.
The owners had typical drydock maintenance undertaken, including repairs to a starboard fuel tank and to the hull. The US Coast Guard attended the vessel for a drydocking examination. Shore power provided electricity for work during the day, and it was shut off at night.
On the day of the fire the port engineer turned on the breakers for the heating system and the lighting, and he conducted a safety briefing with the welding team scheduled to work on the vessel that day. This consisted of a crewmember serving as fire watchman and two welders (both contractors). They were tasked with reinstalling deck plate over top of the head in one of the aft staterooms. As they worked, the roving fire watchman made rounds.
At about 11:55, the watchman noticed what was described as a “strange haze” from the ladderway between the salon on the main deck level and the aft stateroom compartment. He went down to investigate and found flames coming from a bunk in stateroom J, one of seven in the aft compartment. The welding machine was located in this compartment – as it had been for months – but the welders were working in the head, separated by two bulkheads and eight feet from the location of the fire.
He alerted the welders to the existence of a fire, and one of them went to investigate. He saw a small palm-sized flame on the bunk, smoke between a layer of protective plastic sheeting (installed for the job) and the overhead, and pieces of the plastic falling down onto the bunks. He grabbed a fire extinguisher, and directed the other welder to go up the stairs to check on the salon area. There was heavy smoke in the salon, and the smoke was quickly filling up the passageway belowdecks. The welder got down on his back and slid to the stateroom in order to discharge the extinguisher, but this had no effect. He escaped the compartment, shutting off and removing an exhaust fan as he left.
The fire quickly engulfed the salon, starting on the starboard side. Homer’s volunteer fire department arrived quickly, at 12:11. By 14:15 the fire was extinguished.
There were no known sources of heat in stateroom J. The welding machine was recovered intact and undamaged, and the welders were working in a different compartment, so NTSB ruled out hot work as a direct cause of the fire. The agency concluded that the blaze started in the overhead, where the welder had noticed plastic sheeting dripping down.
The NTSB suggested, but did not state with certainty, that a stray welding current from the spool gun back to the welding machine’s work clamp might have overheated a wire in the vessel’s electrical system. There was a 10ft distance between the gun and the clamp, and the return current would have had to pass through the aluminium structure in between. There were also several electrical boxes in stateroom J, which could have been the source of a fault and the start of a fire.
The source was likely electrical in nature but could not be conclusively determined, NTSB said.
Once the fire started, the damage accelerated because of the extensive use of combustible materials in the accommodations space (wood trim, plywood and carpeting throughout, including the bulkheads and drop-ceiling overheads). This was a common and allowable interior construction method for an older “T-boat.”
NTSB advised following best practice and placing the work clamp as close as possible to the area of the welding, rather than 10ft away.