NTSB Releases Report On April 2020 Fire Aboard Dive Support Vessel Iron Maiden
The National Transportation Safety Board (NTSB) has released its Marine Accident Brief detailing a fire aboard the dive support vessel Iron Maiden that took place while the vessel was docked at Allied Shipyard in Larose, La., for repairs. The fire occurred just after 1 a.m. April 16, 2020, with local firefighters extinguishing the flames by about 2:30 a.m. The NTSB estimated damage to the vessel totaling more than $900,000.
The Iron Maiden was built in 1978 by Lockport, La.-based Halter Marine. Originally named the Kathy Candies, the ship first worked as an offshore supply vessel. Tiburon Marine bought the vessel in 2006 and renamed it the Thrasher, then converted it to a dive support vessel the following year. Bisso Marine bought the vessel in 2009 and changed its name to Joseph Bisso. Blue Marlin LLC bought the vessel in December 2019, just four months before the fire, and renamed it the Marlin Responder, then renamed it again the Iron Maiden.
The Iron Maiden arrived at Allied Shipyard March 31, 2020, for drydock inspections and upgrades. While waiting for the shipyard’s drydock to become available, a marine chemist inspected the vessel’s tanks and voids to ensure they were safe for workers and hot work. Then, on April 15, 2020, the Iron Maiden was shifted to a new berth and reconnected to shore power. At 8 a.m. that day, shipyard workers boarded the vessel and began working with acetylene torches on the starboard exhaust trunk and on the forecastle deck adjacent to the starboard side mooring bitt. In its report, the NTSB notes that those work areas were directly above the generator room on the main deck. The No. 1 generator, in particular, which was directly under the starboard exhaust fan, had a fire cloth over it. According to the report, shipyard workers encountered thin metal around the stack trunk, which caused blow-through down to the generator room. A foreman checked the generator room that morning and found no indication of smoke or fire.
At about the same time, contractors were cleaning the vessel’s sewage tank, which was directly below the generator room, so it too could be certified for hot work. Around 10 a.m., shipyard workers in the generator room removed woodwork at the base of the forward bulkhead and “discovered wastage (a hole) in the deck, which exposed them to the vessel’s sewage tank directly below.” Those workers were told at that time, about 2 p.m., to vacate the generator room so the cleaning crew could finish in the sewage tank.
The NTSB noted that shipyard personnel finished work and left the vessel about 4:30 p.m., with the vessel’s company representative disembarking about an hour later. Two vessel crew members left the Iron Maiden about 6 p.m. The vessel remained connected to shore power.
A bridge tender called the Lafourche Parish Fire District at 1:10 a.m. April 16, 2020, to report smoke and flames from the vessel. Fire fighters were on the scene just eight minutes later and discovered a fire extending from the main deck up to the pilothouse. The fire was extinguished by 2:30 a.m., although shipyard personnel found and extinguished a smoldering area behind a fuel tank on the starboard side of the generator room later that morning. Lafourche Parish Fire District investigators later determined, “The fire started in the generator room on the wall area common to the mess area.” They were unable to determine a cause of the fire, although they could not rule out an electrical short as the source.
The NTSB notes that hot work on the starboard exhaust trunk was completed at 9 a.m. April 15, with work in that vicinity and the generator room continuing the rest of the day. No flame or smoke was observed. Furthermore, vessel personnel were on board until 6 pm., with no reports of flames or smoke. Thus, the NTSB determined the fire was not related to the hot work done on the vessel earlier in the day. The NTSB noted the most likely explanation was an electrical short near the panel at the forward bulkhead in the generator room. And with no one on board the vessel, and with the Iron Maiden’s fire detection system “secured” to prevent false alarms during shipyard work, “the fire was able to spread undetected,” the NTSB said.
In issuing its Marine Accident Brief, the NTSB noted: “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.”