What went wrong on the ship that hit the Baltimore bridge?

The Baltimore bridge collapse last month, which saw a 984-foot container ship called the Dali collide with the Francis Scott Key Bridge in Baltimore, Maryland, cost six lives and damaged a major transport artery.

The incident will have long-lasting effects, with a replacement likely to take a decade or more to be built. But what happened to cause it, and how could the marine engineering industry do anything to prevent similar incidents happening in future?

“While the exact causes leading to this unfortunate tragedy remain to be seen, loss of propulsion of the ship seems to be a likely one,” says Jin Wang, professor of marine technology at Liverpool John Moores University. “When the propulsion power is lost in a ship, the manoeuvrability is lost because propellers, thrusters, et cetera would not be operational.”

Catastrophic power failure is most likely because of the nature of the accident, experts argue. “There are modern technologies such as marine radar to help deck officers manoeuvre the ship to go under bridges,” says Wang. “As a result, it is rare to see accidents of this nature.”

Compounding issues are possible contributing factors to make something as unusual as this happen, agrees Joe McKee, a retired marine engineer with more than 50 years of expertise in the field. “There’s no one thing that causes the problem,” says McKee. “These things exist when you get a number of things aligning like holes in cheese. That’s when it goes wrong.”

After analysing video footage of the incident, McKee believes that the Dali experienced some form of power failure that resulted in the ship losing propulsion. A loss of lighting on the vessel, seen on the video, followed by floodlights reappearing on board suggest that at one point, an emergency generator kicked in automatically. “When you get a power out on the main switchboard, everything blacks out and you go onto emergency systems automatically,” he says.

“There’s a number of things that could have caused it,” says McKee. He says it could have been a fuel issue – though he’s sceptical this would be the root cause of the problem. Initial conversation and speculation in the immediate aftermath of the incident suggested that the vessel could have been fuelled with substandard materials.

Instead, he reckons it could well have been a load sharing issue. “Normally when you sail out of a port like that, a ship like that would have two generators on the switchboard,” he says. “It’s possible that one of them has tripped, for whatever reason, and the other has not been able to take the load and dropped off the board because of the excess load.” Working to figure out what happened that tripped and overloaded the generators, and how to prevent it happening again, should be a key finding for the future, he says. “How do you mitigate that?” he asks. “You do drills.”

However, even in that instance, McKee says that the emergency generator ought to have enabled the captain of the vessel to operate the Dali’s steering gear. But having the ability to steer doesn’t help if you’re already moving at a fast rate of knots and experience a power outage. “A ship at that speed will have no steerage,” he says. 

Speculation that the captain should have dropped anchor to stop the vessel wouldn’t have worked to prevent the accident either, McKee believes, because of the speed at which the Dali was going. 

McKee believes that beyond addressing issues with the vessel, further work could be done when it comes to transiting those tricky areas – such as going through the Francis Scott Key Bridge. “That vessel should have had tugs made fast to her, escorting her through that bridge,” he says. It’s possible that the port has been unable to easily keep up with the ballooning scale of the vessels that dock and travel to and from it. 

Whatever the issue, McKee believes lessons will be learned from the Baltimore bridge incident – and they can be taken into future vessel safety and engineering design. One key thing he thinks needs addressing is stronger risk assessment. “There’s safeguards that could have been available to be in place that weren’t in place, so this went from an average problem to a catastrophic problem – and that needs to be identified,” he says.