The NTSB issued an investigation report on the flooding and sinking of the towing vessel ‘Savage Ingenuity’ in Louisiana, in September 2017. The report identified absence of company procedures requiring the closure of weather deck doors at all times while underway.
The incident
At about 0035 local time on 5 September 2017, the crew of the towing vessel Savage Ingenuity was maneuvering two empty tank barges in the Gulf Intracoastal Waterway near mile marker 245 in Sulphur, Louisiana, with the assistance of another vessel. While the tow’s starboard side was almost perpendicular to the current, the vessel heeled to starboard and flooded through an open engine room door.
The towboat sank partially, its bow being held above the water by the head line connected to the barges. All five crewmembers escaped to the barges without reported injury. Approximately 11,800 gallons of diesel oil were released into the waterway, most of which was not recovered. Damage to the Savage Ingenuity was estimated at $1,350,000.
Probable cause
The National Transportation Safety Board determines that the probable cause of the flooding and sinking of the towing vessel Savage Ingenuity was the absence of company procedures requiring the closure of weather deck doors at all times while the vessel was underway, which resulted in rapid downflooding into the engine room when the vessel heeled while perpendicular to a strong current with the head of its tow pushed into a river bank.
Findings
Once the Savage Ingenuity was brought back to the surface, the manholes for the watertight tanks and voids were found to be in place and closed. No damage to the hull was found, aside from the effects of bottom contact and salvage operations. Thus, there was no notable pre-accident hull damage that would have caused or contributed to the sinking.
According to the relief captain on the Savage Ingenuity, he did not think the starboard engine room door was open at the time the vessel started to heel to starboard and take on water on deck. However, the pilot of the Alfred P Cenac III stated that he saw the engine room doors open at the time of the sinking.
Further, the captain of the Savage Ingenuity stated that he observed water flooding into the engine room. The tow was maneuvering about perpendicular to the strong eastbound current at the time it began heeling. Given the vessel’s low freeboard, water washed onto the main deck, reaching the sill of the open engine room door, and downflooded into the engine room.
Once water continuously flooded into the engine room, the list increased, and the engines stopped operating. The flooding overwhelmed the towboat’s reserve buoyancy, causing the vessel to sink.
On towboats, doors to the engine room are often left open to allow for cooling and circulation. The Savage Ingenuity was not fitted with adequate ventilation and cooling systems to allow for the engine room doors to be continuously closed when the engines were running. Consequently, the heat generated in the engine room would also affect the vessel’s adjacent accommodation spaces, where existing ventilation and air conditioning systems could not account for the heat.
The engine room doors, therefore, were left open. Although the relief captain stated that the bilge alarm activated, the vessel’s bilge pump was not started. However, with the rapid ingress of water into the engine room through an open door, the bilge pump likely would not have been able to keep up with the high volume of water and thereby prevent the sinking.
According to the company’s standard operating procedures, while the vessel is operating as a light boat (without any barges in tow), “all hatches (Galley, Engine Room, & Front Hold) on the weather deck shall remain in the closed position.”
Because the Savage Ingenuity was faced up to the barges at the time, this procedure did not technically apply. There was no procedure in place at the time of the accident for management of watertight integrity of the towboat when faced up to barges or during an emergency release of the face wires.
After the accident, the company updated the standard operating procedure by requiring that “all hatches, doors (weather tight and water tight), and porthole[s] (Galley, Engine Room, & Front Hold) on the weather deck shall remain in the closed position” when the vessel is under way. This procedure was also added as a task on the pre-voyage departure checklist.
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