​​The probable cause of the sinking of towing vessel Jim Marko was the captain's decision to continue operations with a known hull breach in the vicinity of the vessel's waterline. Contributing to the rapid sinking was a lack of watertight integrity due to watertight doors on the main deck left open while under way.

​Abandoning Ship

Crewmembers should wear appropriate personal protection equipment for their operations under way and should always wear personal flotation devices when abandoning ship. Two crewmembers on the Jim Marko were barefoot and one did not wear a personal flotation device. The Mississippi River was experiencing high water conditions, which would have posed a heightened risk had crewmembers been forced to abandon ship into the water.

Watertight Integrity

A hole in the side shell of a vessel, especially a large one near the waterline, poses a serious risk. When a potential hull breach has been identified, operations should be halted until repairs can be made or the crew can determine that the damage does not affect seaworthiness.

Watertight Doors

Water- and weathertight doors should be kept closed when a vessel is under way, unless the crew must pass through them. These doors are critical for preventing ingress of water or stopping its spread if a hull breach ​and/or flooding occurs.