The National Transportation Safety Board (NTSB) today released findings on a towing vessel accident from March 26, 2023, where the nearly 60-year-old vessel Uncle Blue partially sank on the Lower Mississippi River near Ascension Parish, La.
While towing an empty barge, the Uncle Blue began taking on water, eventually flooding and sinking. During the salvage process, NTSB investigators observed water pouring from holes in the portside shell plating of the vessel's lazarette. Further inspection revealed multiple wastage holes and doubler plates near these areas. The NTSB determined that the vessel’s hull was inadequately maintained, exacerbating the damage.
“Although doubler plating can be used as a temporary repair solution, it is not generally suitable as a permanent repair for a vessel’s hull,” investigators said. “Vessel owners should crop out wasted steel on the hull and replace it by inserting new plating instead of covering it up with doubler plating.”
The investigation also uncovered open pipe runs inside the hull that previously housed rods. These pipes, corroded and in some cases missing, contributed to the progressive flooding of the vessel’s voids and engine room.
The report underscores the importance of regular maintenance and inspections for steel-hulled vessels, noting, “Steel hulls are susceptible to corrosion, erosion, and damage over time,” investigators said. “To avoid flooding or weakening of the hull, it is good marine practice for owners to conduct regular oversight and maintenance of hulls, including between drydock periods. An effective maintenance and hull inspection program should proactively address potential steel wastage, identify hull and watertight integrity deficiencies, and ensure corrosion issues are repaired in a timely manner by permanent means.”
In addition to the hull's condition, the absence of a high-water bilge sensor in the lazarette was identified as a factor that delayed the detection of flooding. The only sensor on the vessel was located at the forward end of the engine room.
Fortunately, no injuries or pollution resulted from the incident. However, the vessel sustained an estimated $500,000 in damages.
The full NTSB Marine Investigation Report 24-23 is available online for further details.
