NTSB Releases Accident Report On 2019 Sinking Of OSRV Assist Vessel
The National Transportation Safety Board (NTSB) has released a Marine Accident Brief for an incident that took place January 16, 2019, near Boothville Anchorage on the Lower Mississippi River at Mile 18. The incident involved a Marine Spill Response Corporation (MSRC) oil spill response vessel and its workboat, the MSRC 8-1, which capsized and sank during a training exercise. The two crew members aboard MSRC 8-1 died in the incident.
MSRC’s Louisiana Responder is a 210-foot oil spill response vessel that was docked at Fort Jackson, La., on the right descending bank of the Mississippi River the morning of the incident. The MSRC 8-1 was a 32-foot aluminum vessel assigned to the Louisiana Responder to assist in deploying boom and other duties during an oil spill. During an exercise or spill response, the MSRC 8-1 would be deployed from the stern of the Louisiana Responder.
On the morning of the incident, a team of seven MSRC land-based responders and a federal Bureau of Safety and Environmental Enforcement (BSEE) observer boarded the Louisiana Responder, joining the vessel’s crew of six for an oil spill containment exercise to be held downriver at the Boothville Anchorage. The plan was to deploy oil spill boom in a “J” configuration. The boom would be deployed from the Louisiana Responder, and the MSRC 8-1 would tow the boom ahead of the Louisiana Responder, forming the longer side of the J.
During a real oil-recovery operation, the boom would channel oil toward the Louisiana Responder, which would skim oil off the surface. The team’s master responder volunteered to pilot the workboat while a responder, the newest member of the team, asked to serve as deckhand aboard the MSRC 8-1 for the exercise. The Louisiana Responder departed for the anchorage about 8:30 a.m. Weather conditions at the time included air temperature of 51 degrees, water temperature of 43 degrees, and river currents “noted as being ‘3.5 knots, at least,’” according to the NTSB report.
Once on site, the crew launched the workboat with the crew of two. With the boom ready to be deployed, the master responder piloted the workboat alongside the Louisiana Responder, with the deckhand securing the boom towline to a bitt on the port bow. When the boom was paid out, the deckhand transferred the towline to an H-bitt located near amidships of the MSRC 8-1 in order to maneuver into the J configuration. About that time, crew members aboard the Louisiana Responder saw the MSRC 8-1 turn “a few degrees to port,” which the report described as “unexpected.” A few second later, the MSRC 8-1 turned hard to starboard, putting the boat perpendicular to the current. Crew aboard the Louisiana Responder noticed the boom towline “snapped at” the deckhand, causing the deckhand to drop the towline and run toward the boat’s cabin. As the boat drifted in the current, tension mounted on the towline at the H-bitt, which caused the boat to roll over on its side. The MSRC 8-1 rolled a number of times side to side until it finally fully capsized, with the boom still attached to the Louisiana Responder.
The Louisiana Responder launched its small boat, which was soon joined by a U.S. Coast Guard response boat, a Coast Guard rescue swimmer from a passing helicopter and an Associated Branch Pilots assist vessel. The Louisiana Responder’s small boat crew and the rescue swimmer both heard the master responder and the younger responder calling through the hull of the workboat. The crew aboard the Louisiana Responder proceeded to haul in the boom, with plans to hoist the workboat out of the water when it got close enough. In the process, the rescue swimmer attempted to reach the workboat’s trapped crew members but was unable due to the strong current and opaque water.
Eventually, the crew aboard the Louisiana Responder was able to retrieve all 660 feet of the oil boom, but they were unable to haul in any of the towline. At about 11:20 a.m., rescuers noticed the MSRC 8-1 begin to take on more water and fishtail. Then they heard a popping sound as the towline parted from the workboat. Shortly thereafter, the vessel rolled sideways, then sank.
Remains of the master responder were later recovered aboard the workboat when it was raised. The deckhand was never found.
NTSB reports that the workboat’s manual cautioned against a towline attached to the H-bitt straying beyond 5 to 10 degrees astern. Anything beyond that put the vessel at risk for capsizing. NTSB reports MSRC after the incident modified its other workboats, “installing a towline guide on the stern and a buoyancy collar at the waterline” to prevent the same set of conditions from occurring in the future.
After its investigation, NTSB determined the probable cause of the capsizing of MSRC 8-1 to be “the boat becoming perpendicular to a strong river current, for an undetermined reason, while tethered to the oil spill response vessel Louisiana Responder. Contributing to the accident was the unforeseen risk associated with conducting the exercise in a strong current, which also contributed to the severity of the outcome by hampering rescue efforts.”