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Probe: Manifold crack, foam ignition led to Quebec tour-boat fire

Feb 26, 2016 12:47 PM

Improper use of polyurethane foam insulation in an engine compartment contributed to a 2014 fire aboard a St. Lawrence River tour boat, the Transportation Safety Board of Canada (TSB) said.

Thirty-three passengers on a sightseeing cruise were safely evacuated when the passenger vessel La Relève II had an engine-room fire when oil-soaked polyurethane foam insulation ignited near Havre-St.-Pierre on Aug. 11, 2014. 

In a recent report, TSB investigators pointed out that polyurethane foam is prohibited for use on wooden passenger vessels like La Relève II. A burst hose and cracked exhaust manifold were the initial events that led to overheating and ultimately the fire. 

Shortly after departure at 1300, the master noticed a power drop in the engine. Passengers observed smoke coming from the engine room compartment cover and the outside engine compartment vents.

At 1335 the master broadcast a mayday on Channel 16 stating he had a fire on board and was abandoning the vessel and ordered the deck hand to prepare the life rafts. The master activated one charge of the vessel’s CO2 fixed fire suppression system, closed the dampers for the two engine compartment vents and shut off the fuel supply to the engine, the TSB report said.

The master launched the stern life raft, but both buoyancy tubes inflated only briefly then lost gas pressure and deflated, rendering the life raft unusable, the investigators wrote.

The master then launched the life raft on the port side of the vessel. Both buoyancy tubes began to inflate, but the lower buoyancy tube deflated shortly afterward. The life raft was then pulled alongside the vessel. The life raft on the starboard side of the vessel inflated fully and was also pulled alongside the vessel.

The master helped the passengers board the starboard life raft and ordered the deck hand to take charge of the port life raft. The deck hand, assisted by one of the passengers, helped passengers board that raft. 

At 1343, the master informed MCTS Rivière-au-Renard that about 90 percent of the passengers had boarded the life rafts and that the second charge of CO2 had been released into the engine compartment. The good Samaritan vessels Le Dauphin and Le Capitaine Yockell arrived and began to transfer passengers from the rafts. The vessel Cap De Rabast arrived and supplied fire extinguishers to La Relève II. The final passenger was transferred directly to Le Capitaine Yockell at 1402, and Le Capitaine Yockell and Le Dauphin headed toward Havre-Saint-Pierre. Two passengers were taken to a hospital.

Cap De Rabast towed La Relève II toward the marina. While under tow, the master opened the engine compartment cover briefly and discharged two fire extinguishers into the compartment. Once moored in Havre-St.-Pierre, local firefighters boarded the vessel and declared the fire extinguished.

The TSB investigation determined that La Relève II’s engine lost coolant when the rubber hose connected to the exhaust manifold outlet burst. The engine then overheated, causing a crack in the exhaust manifold.

The damaged hose and crack in the manifold directed the hot exhaust gases onto the underside of the engine compartment cover, damaging the insulation and exposing the layer of polyurethane foam.

The engine oil filling cap melted, allowing the engine to spray oil onto the foam, the investigators wrote. The foam became soaked in oil and was exposed to the hot exhaust gases.

The TSB found that two of the three life rafts failed to inflate fully due to buoyancy tube ruptures at the inflation valves. “The ruptures may have been caused by the lifelines becoming entangled with the inflation valve assemblies and creating excessive strain in the tubes,” the report suggested.

In September 2014, the TSB issued a marine safety advisory letter to inform Survitec Group Ltd., the manufacturer of the life rafts, about the malfunction of the two rafts and the damage that they sustained.

In its response, Survitec said that in testing a similar raft, the company could not replicate the failure.

Later in September 2014, the TSB issued a marine safety information letter to inform Transport Canada (TC) about the risks associated with the use of thermal-acoustic insulation incorporating aluminized Mylar in machinery compartments.

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