NTSB issued an investigation report on the fire onboard the dive support vessel Iron Maiden, while docked at a shipyard in Louisiana, in April 2020. The investigation identified an electrical short from an unidentified source as key cause of the incident.
The incident
On April 16, 2020, about 0110 local time, a fire onboard the dive support vessel Iron Maiden occurred while the vessel was docked at the Allied Shipyard in Larose, Louisiana.
Local firefighters extinguished the fire at 0225. There was no one aboard the vessel at the time of the fire.
There were neither pollution nor injuries, but damage to the vessel was estimated at greater than $900,000.
Probable cause
The National Transportation Safety Board determines that the probable cause of the fire aboard the dive support vessel Iron Maiden was an electrical short from an unidentified source located on the forward bulkhead within the generator room.
Contributing to the undetected propagation of the fire was the lack of continuous monitoring of the vessel while it was docked at the shipyard.
Analysis
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The hot work on the starboard exhaust trunk and starboard area of the forecastle deck was completed at 0900 on April 15. After the completion of the hot work, a shipyard supervisor inspected the area, identifying no flame or smoke. During the remainder of the day, shipyard and contract personnel worked in and around the generator room until 1630, and there were no observations of flame or smoke within the area. Vessel crew members remained onboard the vessel until 1800 and made no reports of flame or smoke prior to departing the vessel.
Based on the location of the hot work and the initial location of the fire within the generator room (as determined by the LaFourche Parish Fire District investigator’s report), the hot work conducted onboard the vessel was not the source of the fire.
While there was extensive damage throughout the generator room, the fire pattern and damage indicated that the area of ignition where the fire started was the forward bulkhead.
Because the battery charger, alarm panel, and generator push button start-stop panel were in the area of fire ignition identified by fire investigators, one of these components may have been the source of the fire as the result of an electrical short.
However, the exact location of the source of the fire could not be identified by fire investigators. At some point, as the fire grew, the wood paneling and furniture in the space above the generator room ignited. After the wood and other combustible items caught fire, they provided a path for the fire to expand from the generator room up into the living quarters.
With the vessel’s fire detection system secured for the shipyard period and no continuous or periodic scheduled monitoring of the vessel by shipyard or owner personnel, the fire was able to spread undetected.
Lessons learned
-Continuous Monitoring of Inactive Vessels
Fire and flooding are risks for both crewed and unattended vessels. To protect personnel, property, and the environment, it is good marine practice for owners, operators, and shipyard managers to coordinate and implement some form of continuous monitoring for vessels undergoing maintenance in a shipyard, in lay-up, or in some other inactive period without regular crews aboard. Continuous monitoring can consist of scheduled security rounds and/or active monitoring with sensing and alarm systems.
