NTSB Issues Report On June 2023 Partial Sinking Of Towboat
A wire nut lodged in a valve resulted in the partial sinking of a towing vessel and more than $176,000 in damage, the National Transportation Safety Board reported April 23.
The NTSB issued results of its investigation into the partial sinking of the mv. Joanne Marie June 25, 2023, while moored at a shipyard on the Harvey Canal near New Orleans, La.
The Joanne Marie was found partially submerged a day and a half after being moored and deactivated at the Bollinger Quick Repair shipyard. Owned by Marquette Transportation, the Joanne Marie was typically contracted out to customers who wanted to use it for specific jobs; when not being used by a customer, it was deactivated and returned to the shipyard where it would remain, unattended, until its next assignment.
NTSB investigators found a wire nut lodged in a spring-loaded check valve on a bilge pump discharge line for the propeller shaft seal cofferdam, an enclosed box with an open top that collected dripping seal water when the towboat was underway. The wire nut obstructed the valve and left it stuck partially open, NTSB said. Investigators also found the discharge line’s overboard shutoff valve before the through-hull pipe had been left open, as the operating company’s towing safety management system (TSMS) did not direct the crew to close it during deactivation.
In addition, the through-hull pipe for the vessel’s cofferdam overboard discharge was located close to the water line, which allowed water to enter the discharge line. Investigators determined that with the spring-loaded check valve stuck partially open and the vessel’s overboard shutoff valve open, water was able to enter the through-hull pipe opening, causing the cofferdam to overflow and water to flood the engineroom, the NTSB report stated.
The NTSB also found the operating company’s inadequate procedures for securing unattended vessels contributed to the sinking. Following the sinking, the operating company modified its checklist for vessels entering deactivation to include closing the overboard shutoff valve when a vessel is not connected to shore power.
“It is good marine practice for owners and operators of towing vessels to assess risks and develop tasks in their towing safety management system for vessels that are unattended or in layup status,” the report said. “TSMS task lists for such vessels should address factors in the configuration of the vessel that could lead to a casualty.”
The investigation report is available here: www.ntsb.gov/investigations/AccidentReports/Reports/MIR2407.pdf.
Caption for photo: The mv. Joanne Marie partially sank at its mooring on the Harvey Canal on June 25, 2023. (U.S. Coast Guard photo)
