Causes and Prevention of Towboat Flooding Incident in New Orleans

The sinking of the towboat Joanne Marie at a shipyard in New Orleans last year was caused by an open overboard shutoff valve and a failed check valve, according to the NTSB. The incident occurred while the vessel was in layup without power or crew, resulting in partial flooding but no injuries. The crew had left the fuel tank crossover valves and overboard shutoff valves open as part of routine practice, leading to the flooding when water flowed back through the line due to the vessel sitting lower in the water than usual.

The damage to the Joanne Marie was relatively limited, with the vessel stable and only a few gallons of fuel released into the environment. The cost of repair totaled about $175,000, with damage to the main engines, diesel generators, electrical equipment, and crew spaces. Investigators found that a simple plastic wire nut had jammed open the check valve, allowing water to flood the engine room. Lessons learned from the incident led the operator to modify their layup checklist to include closing the overboard discharge valve when the vessel has no power.

To prevent similar incidents in the future, the NTSB recommended operators consider closing through-hull fitting valves during layup, as well as installing high-water bilge alarms and fire detection systems. These measures can help facilitate early detection and mitigation of potential safety risks such as flooding or fire, improving overall vessel safety during periods of inactivity.

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