The National Transportation Safety Board (NTSB) released a post-accident report of the towing vessel Mackenzie Rose and its collision with a railroad bridge in Chesapeake, Virginia on June 15, 2024.
This incident resulted in damages when the loaded deck barge Weeks 281 struck the western section of the Norfolk and Portsmouth Belt Line Railroad Bridge at 16:26.
The 96.4-foot-long (29.4-metre) vessel departed a Coastal Precast Systems facility at 15:00 while en route to New York with five crew members. The mate conning the vessel from the upper wheelhouse used autopilot while transiting outbound in the 30-foot (9.1-metre) deep channel.
As the tow approached the 378-foot-long (115.2-metre) lift bridge, electronic data showed the vessel began swinging to port at a rate of 12 degrees per minute.
The mate reported that the autopilot switched off without an alarm as the tow drew near to the bridge, though investigators were later unable to replicate this technical failure.
CCTV footage recorded the tow continuing to push ahead on the structure for nine seconds following the initial contact. The NTSB noted that forward propeller wash remained visible during this time, with engine exhaust changes only appearing after the nine-second interval.
Records suggested the mate was likely experiencing fatigue after reversing his awake and sleep cycles three days before the accident. The NTSB concluded that the operating company failed to immediately notify the US Coast Guard of the strike, which displaced the western span by about 6.5 feet (1.98 metres).
A loss of control by the mate, potentially due to fatigue or an error switching steering modes, was cited as the probable cause of the contact.
Following repairs costing the Norfolk and Portsmouth Belt Line Railroad Company $15.8 million, the bridge returned to reduced service on November 6, 2024.