NTSB issued its investigation of the 2 September 2015 collision between two towboats and barges. The towboat P. B. Shah was upbound pushing 24 barges on the Lower Mississippi River at mile marker (mm) 937, near Columbus, Kentucky, when two of its barges collided with two of four barges being pushed downbound by the towboat Dewey R. No one was injured; however, the accident resulted in the discharge of 120,000 gallons of clarified slurry oil into the river and an estimated $1.1 million in damages.
The incident
On September 2, 2015, at 1959 central daylight time, the uninspected towing vessel P. B. Shah was upbound pushing 24 barges on the Lower Mississippi River at mile marker (mm) 937, near Columbus, Kentucky, when two of its barges collided with two of four barges being pushed downbound by the uninspected towing vessel Dewey R. No one was injured; however, the accident resulted in the discharge of 120,000 gallons of clarified slurry oil into the river and an estimated $1.1 million in damages.
The P. B. Shah captain erred when he initiated a port-to-port (one whistle) passing on the radio with the Dewey R captain. He had meant to arrange a starboard-to-starboard (two-whistle) passing, but the captain was distracted by the many tasks associated with preparing for his arrival at the Ingram facility.
This included having a cell phone conversation with the boat store to discuss a grocery delivery and meeting with the mate to discuss upcoming tasks, both around the same time the passing arrangement was made with the Dewey R. “Sliding underneath the point” is an action, as described by pilots with larger tows coming upbound around Belmont Point, that allows equal or smaller southbound tows to come around Belmont Point with a following current without worrying about their vessel sliding across the river into the upbound tow.
The P. B. Shah captain’s radio transmission saying he would “be underneath Belmont Point” and the AIS position data showing the tow’s movement towards the right descending bank are consistent with a starboard-to-starboard passing, indicating that this was the captain’s intention.
As the operator of a downbound vessel on the Western Rivers, the Dewey R captain made a mistake by not following the inland navigation rules. Per the rules, the downbound vessel “shall have the right-of-way over an upbound vessel…[and] shall propose the manner and place of passage.”
The Dewey R captain should have assessed the risk of collision presented by the two alternative meeting arrangements, chosen the option that did not include passing in front of the P. B. Shah tow, and then used his privilege as the downbound vessel to overrule the P. B. Shah captain’s change to a two-whistle meeting arrangement. Instead, because the Dewey R captain doubted his understanding of the original agreement, he made the decision to cross the river based on the P. B. Shah captain saying he was bringing his tow around to the port, in an attempt to steer clear of the P. B. Shah and to conduct a two-whistle pass.
Probable Cause
The National Transportation Safety Board determines that the probable cause of the collision between the P. B. Shahtow and the Dewey R tow was the impact of distraction upon the decision-making and recollection of the captain of the P. B. Shah. Contributing to the collision was the failure of both captains to monitor the progress and effectiveness of the meeting proposal and take appropriate action to avoid the collision.
Further details may be found in the Marine Accident Brief below
Source: NTSB
