NTSB Releases Report Detailing 2018 Allision At Louisiana’s Sunshine Bridge
At about 1:40 a.m. October 12, 2018, the mv. Kristin Alexis was headed upriver on the Lower Mississippi River near St. James Parish, La., pushing the crane barge Mr. Ervin, when the crane struck the Sunshine Bridge, a cantilever bridge at Mile 167.5 that connects the communities of Darrow, Sorrento and Convent on the east bank to Donaldsonville on the west bank.
At the time, the mv. Kristin Alexis was part of Marquette Transportation Company’s Gulf-Inland fleet, while the Mr. Ervin was owned by Cooper Consolidated.
The allision, which occurred as the vessel and tow attempted to go through the west bank span of the bridge, caused an estimated $8,500 in damages to the crane. The National Transportation Safety Board (NTSB), which released its Marine Accident Brief last month detailing the investigation into the incident, estimated that damage to the bridge totaled a staggering $6.7 million.
The allision damaged significant weight-bearing members on the bridge, placing the bridge at risk of collapse. The river crossing was completely closed until the following December. Repairs were finally completed in March 2019, at which time traffic returned to normal. The allision and subsequent closure of the bridge caused a major disruption to traffic patterns, with residents having to travel more than a half hour in either direction just to reach the nearest river crossing.
At the time of the incident, the Kristin Alexis was under a 13-month charter with Cooper Consolidated, with vessels in Marquette’s Gulf-Inland group providing towing services, “including moving crane barges and other barges from one work site to another in the vicinity of the Convent and Darrow fleets,” according to the NTSB report.
On the day before the incident, the Kristin Alexis was doing fleet work at Cooper Consolidated’s Convent fleet at Mile 161.5. Shortly before midnight, a Cooper Consolidated dispatcher told the captain aboard the Kristin Alexis that the crew’s next assignment would be to move the Mr. Ervin up to the company’s Darrow fleet. The move would require passing under the Sunshine Bridge, which has a “channel” or main span and a west bank span for passing vessel traffic.
The Mr. Ervin measures 75 feet wide and 191 feet long. When stowed, the crane has an air draft of about 136 feet, measured from the water to the top of the crane’s A-frame. According to the NTSB, prior to the move, Cooper Consolidated’s managing director of stevedoring and maintenance identified the river stage at Donaldsonville, which was 18.37 feet, and “calculated the minimum vertical clearance of the Sunshine Bridge to be ‘151 or 152 feet.’” The managing director determined that to be sufficient for the Mr. Ervin to pass under the bridge, though that information was relayed neither to the dispatcher nor the vessel crew. The NTSB report noted that the captain on duty aboard the Kristin Alexis entered “37” on a voyage information form in the space for “maximum air draft.” The captain told NTSB the number indicated the Kristin Alexis’ air draft and not that of the crane.
The captain faced up to the port side of the crane barge’s stern at about 11:30 p.m. A grab bucket on the deck of the Mr. Ervin partially obscured the view from the Kristin Alexis’ wheelhouse, and the captain requested the Cooper Consolidated crew to move it. After a 20-minute discussion, Cooper officials denied the request, and the Kristin Alexis got underway about 11:50 p.m. on October 11. “The captain stated that he did not know the exact air draft of the crane but that someone at the dock told him it was 130 feet,” the report stated. According to NTSB, the captain also stated he did not know the overhead clearance of the Sunshine Bridge, though he said he had pushed the Mr. Ervin under the main span of the bridge before with no problem. The pilot on board stated he had pushed crane barges under the bridge before, though never the Mr. Ervin.
Shortly after getting underway, the pilot came up to the wheelhouse for watch change.
“According to the pilot, he and the captain typically did a thorough watch handover, which would include a discussion of the operations, the weather, the river conditions and, if planned, a bridge transit, but this time was not typical because the captain was still ‘upset’ about the placement of the grab bucket,” the report said. “The pilot said that no information about the crane was provided during the handover, and he did not know the crane barge’s air draft, but because of his experience with other Cooper cranes, believed it was about 130 feet.”
A post-accident measurement by the U.S. Coast Guard determined the Mr Ervin’s air draft to be almost 136 feet.
As the pilot steered the Kristin Alexis upriver, the pilot navigated using Rose Point, which, according to the NTSB report, was based on the National Oceanic and Atmospheric Administration’s nautical chart for the area. According to the report, Rose Point showed a vertical clearance of 132.9 feet for both spans of the bridge. The NOAA nautical chart displayed a single vertical clearance for the entire bridge of 133 feet. NTSB’s investigation found that NOAA’s nautical charts for the Lower Mississippi River list only a single vertical clearance figure for other bridges with multiple spans.
In actuality, given the river stage of 18.37 feet at the U.S. Army Corps of Engineers’ Donaldsonville gage, the minimum clearance for the main channel span at the time of the incident was 153.32 feet. Under that span, the Mr. Ervin would have had close to 17 feet of clearance. At the point of impact, though, within the west bank span, the survey-based vertical clearance at the time was 133.03 feet, meaning the Mr. Ervin was about 2.72 feet too tall.
According to NTSB, the impact “struck the lowest horizontal support chord and lateral braces of the west span of the Sunshine Bridge” and brought the tow to a stop, with the Mr. Ervin lodged underneath the bridge.
The captain, who was still awake, returned to the wheelhouse and, after discussing what happened, “he relieved the pilot.” The pilot called Vessel Traffic Service New Orleans, the Marquette port captain and Coast Guard Sector New Orleans. A bridge inspector arrived within an hour and promptly closed the bridge to traffic. Later, personnel from Cooper Consolidated arrived to add ballast water to the crane barge, thus lowering it in the water and freeing it from the bridge. The mv. Kristin Alexis was sent to dock at Mile 164, while the mv. Capt Whitey towed the Mr. Ervin up to Darrow that morning.
The NTSB noted that, after the incident, Cooper Consolidated began directing vessels towing its crane barges to use the main channel span. The report also noted that, six weeks prior to the Mr. Ervin allision, another Marquette towboat pushed another company’s crane barge into the west span of the Gramercy Bridge, downriver from the Sunshine Bridge. “The company did not make all employees aware of that incident or provide direction on how to avoid this type of accident in the future,” the NTSB said in the report. The NTSB also found that the captain and pilot failed to communicate transit guidelines or to properly fill out voyage forms. Likewise, the NTSB noted that the Marquette safety management system “did not provide clear guidance on how to calculate overhead clearance.”
In the end, the NTSB found that the probable cause of the allision at the Sunshine Bridge was “inadequate voyage planning and watch turnover between the captain and pilot,” which led to the pilot taking the bridge’s west span. The agency also said “lack of company oversight” and nautical charts that “did not reflect the actual vertical clearance of the west span” contributed to the incident.
The NTSB ended its report by recommending that Marquette develop a detailed voyage plan that identifies risks like clearance limitations and develop an audit plan to verify captains and pilots know and follow bridge transit procedures. Likewise, the NTSB recommended that NOAA review and update bridge data and charts “to include vertical clearance information for all navigable bridge spans.”