NTSB Releases Report On September 2019 Rupture Of Tank Barge In Tenn-Tom Lock
The National Transportation Safety Board (NTSB) has released its Marine Accident Brief detailing a September 8, 2019, incident involving the mv. Savage Voyager and a pair of tank barges as the tow transited the Jamie Whitten Lock & Dam on the Tennessee-Tombigbee Waterway.
The Savage Voyager was locking through just before 4 a.m. that morning. As the water level dropped within the lock chamber, which offers a whopping 84-foot maximum lift, the bow of barge PBL 3422 came to rest on the lock’s upper gate sill. As the water level continued to drop, the weight and stress on the barge caused a hull failure and cargo tank breach.
“About 117,030 gallons (2,786 barrels) of crude oil were released into the lock,” according to the NTSB report. “No injuries were reported. The damaged barge cost $402,294 to repair, and costs to return the lock to service 18 days later were about $4 million.”
Four days earlier, on September 4, 2019, the Savage Voyager’s crew loaded both its tank barges at a facility on the Upper Mississippi River near Hartford, Ill. The ship’s log noted that PBL 3422 was loaded with a total of 20,260.6 barrels of crude oil, while the other, SMS 30056, received 20,309.6 barrels of crude oil. SMS 30056 was the lead barge, and the barges were arranged stern to stern. The Savage Voyager departed southbound en route to a refinery in Tuscaloosa, Ala., at 4:20 p.m. that afternoon. The NTSB report noted the total length of the tow was 678.5 feet, with a maximum draft of 10 feet.
The Savage Voyager arrived to the Jamie Whitten Lock & Dam, the uppermost lock on the Tenn-Tom, at about 3:30 a.m. on September 8. About 15 minutes later, the vessel was granted permission to enter the lock chamber. According to the NTSB report, a yellow vertical line roughly a foot wide is painted at the upper end of the lock chamber to mark the upper gate’s miter sill. Upon entering the lock, the Savage Voyager crew moored the bow of SMS 30056 (the forward end of the tow) to one the lock’s lower floating mooring bitts and the bow of the PBL 3422 (at the rear of the tow) to an upper floating mooring bitt. Then, due to the overall length of the tow, the Savage Voyager was released from the tow and positioned along the port side of PBL 3422.
The deckhand on duty stated that he then returned to the rake of the PBL 3422, noting that the barge was in the correct position at that time.
“The lock operator stated he looked at the lock chamber’s camera feed to ‘make sure that he’s on the inside of the line,’” according to the NTSB report. “One he was satisfied, he closed the upper gate, then closed the fill valves and opened the emptying valves so that the water level began to drop.”
Within seconds of the water level beginning to go down, the deckhand positioned on the PBL 3422 noticed the barge had settled onto the miter sill. The deckhand radioed to the pilot, asking him to push the tow forward a bit. The deckhand also asked the tankerman aboard the lead barge to slacken the bow line.
“In the wheelhouse, the pilot throttled both engines full ahead in an attempt to free the barge and heard ‘a loud noise,’” the report stated.
The pilot then called for the lock operator to stop releasing water from the chamber. The lock operator said he looked out the window and saw the rake of the barge about three feet out of the water. He immediately began the process to close the emptying valves, but “he could not stop the water from lowering until the valve stop sequence completed,” according to the report. With the water level continuing to go down, the rake of the PBL 3422 bent up at a 45-degree angle. Shortly thereafter, the rake slipped off the miter sill and dropped back into the water. By the time the water level stabilized, the water was about 13 feet below the upper miter sill.
As the crew worked to assess the situation and replace lines that had parted during the incident, they noticed crude oil escaping from the PBL 3422 into the chamber.
“The captain and pilot shut down the vessel’s engines and ventilation to stop vapors from the crude oil from entering the wheelhouse, and the crew took shelter within the Savage Voyager,” the NTSB report stated.
Later, the lock operator raised the water level in the chamber to make it easier for the Savage Voyager crew to go ashore.
That day, the U.S. Coast Guard closed the waterway between Miles 410 and 414. Absorbent boom was placed downstream of the lock. In the days that followed, oil was pumped from the damaged tank into SMS 30056 and a vacuum truck began removing oil from the chamber. In all, an estimated 2,786 barrels of oil was released into the chamber, with an estimated 22 barrels unrecoverable. About a week later, another vessel, the Savage Innovator, arrived on the scene with another tank barge. The remaining oil was then pumped into the SMS 30037. The Savage Voyager departed for the Tuscaloosa refinery on September 19, with SMS 30056 and SMS 30037 in tow. That same day, the Savage Innovator left with PBL 3422 for a New Orleans-area shipyard.
At the lock, cleanup crews commenced the lengthy decontamination process. The lock reopened September 25.
In post-incident testing, Corps officials determined, with the barge rake drifting backward and crossing the yellow warning line, it would have taken about 3.7 minutes for the barge’s tow knees to contact the sill.
“Had the deck crew been vigilantly monitoring the vessel’s position, they would have noticed the barge was out of position before it became stuck on the sill and could have alerted the pilot,” the report stated.
With that in mind, NTSB investigators determined the probable cause of the incident was “the tow moving out of position in the lock chamber while locking down when the crew did not effectively monitor and maintain the vessel’s position during its descent, resulting in the aft barge becoming hung on the upper gate miter sill.”
The report concluded with a word of caution to lock operators and vessel crews: “Although locking operations can seem routine, the margins for safety are frequently low. Maintaining vessel position and communication with the lock operator are critical practices to ensure safe lockage. Crews should avoid complacency and vigilantly monitor lines at all times to prevent ‘running’ in a lock.”