NTSB: Back-to-Back Hydraulic Hose Failures Caused Destructive Blaze
The NTSB has determined that two back-to-back hydraulic hose failures caused the destruction of a fishing vessel off the coast of Cape Cod in 2021. Once the fire started, an open pipe tunnel sped up the spread of the flames into other parts of the vessel, making the conflagration harder to fight.
On April 30, 2021, while fishing for haddock at Georges Bank, the crew of the fishing vessel Nobska spotted a fire on the lagging of the main engine's exhaust pipe. After putting it out, they determined that the source of the fuel was a broken hydraulic hose located in a pipe tunnel, which ran between the wheelhouse and the engine room.
The crew replaced the hydraulic hose and removed the oil-soaked lagging from the exhaust pipe, leaving the pipe bare. With the situation apparently resolved, they went back to fishing.
About four hours later, the captain of the Nobska noticed that there was black smoke coming out from underneath the wheelhouse winch-control console - the upper terminus of the same pipe tunnel. Within moments, the wheelhouse was ablaze. Attempts to put out the fire were unsuccessful, and the crew prepared to abandon ship.
After attempts to extinguish the fire failed, the crew activated the vessel’s EPIRB and made ready to abandon ship. A U.S. Coast Guard helicopter safely rescued the crew from the stern of the vessel, and no pollution or injuries were reported. The vessel was declared a total loss at an estimated cost of $2.4 million.
NTSB determined that the probable cause of the second fire was the failure of another hydraulic hose, followed by ignition of an oil spray on the exposed exhaust pipe. The initial fire may have compromised a different hydraulic hose in the pipe tunnel; alternately, the work conducted to replace the first failed hose could have resulted in damage to another, adjacent hose.
The pipe tunnel itself was likely a contributing factor to the vessel's destruction, NTSB concluded.
“The pipe/hose tunnel on board the Nobska, which extended from the engine room up two decks to the wheelhouse, did not have any insulation, pipe/cable fire stops, or other barriers to prevent the passage of smoke, heat, and fire,” the report concluded. “This type of unprotected vertical tunnel has the potential to provide a pathway for fires to spread quickly outside of the space of origination."