Tuesday’s accident was at least the second in a little more than a month that a container ship has struck a major road bridge, raising questions about safety standards for increasingly large ships and the ability of bridges around the world to withstand crashes.
On February 22 in Guangzhou, a port in southern China, a much smaller ship carrying stacks of containers hit the base of a two-lane bridge, causing vehicles to fall. Officials said five people were killed.
The crashes have also raised questions about whether more ships should be required to be ready to drop anchor quickly during port emergencies and whether tugboats should accompany more vessels as they enter and leave ports.
There has been no final report on the Guangzhou incident, and investigators have barely begun to look into what happened in Baltimore. But ship collision barriers are standard around bridge support piers over major waterways, such as the entrance to Baltimore Harbor. The Verrazzano-Narrows Bridge in New York, for example, has massive concrete and rock barriers around the pier bases that support it.
It was not immediately clear how old the barriers are around the piers that supported the bridge in Baltimore. The bridge was built nearly half a century ago and was designed before then. Boats have gotten much bigger in that time.
The accident in Guangzhou occurred in a less important waterway, a small channel of the Pearl River. The bridge there was equipped with devices designed to protect the piers in the event of a ship collision. The project was supposed to be completed by 2022, but has been delayed and the latest target for completion was August this year, according to China Central Television, the state broadcaster.
Harbor pilots and the crews of many large ships have two anchors ready to drop as they enter or leave a port, in case an emergency such as a loss of power means they must try to make a quick stop. Vasilios M. Karatzas, managing director of Karatzas Marine Advisors, a ship inspection firm in New York, said that while he had seen tanker crews routinely take this precaution, it was less common for container ships.
“The anchors have to be unlocked and ready to drop, and that takes some time to prepare, as generally the crew members on the bow have to unlock and release them,” he said. “This is not something you can do in an emergency.”
Large ships are often accompanied by tugboats as they leave or enter ports so that the tugboats can pull them out of harm’s way if the ship is in difficulty. It was not immediately clear if tugboats were accompanying the ship that struck the bridge on Tuesday.
The ship in Baltimore was leaving the harbor as a spring tide rushed out of the harbor. The moon was still almost completely full, having reached its maximum less than 24 hours earlier.
The spring full moon is associated with some of the largest tidal changes in local sea level. And while Baltimore Harbor experiences fairly minor changes even during the full moon spring tide, tidal water movements could have been a factor in the bridge impact.
“The tide increases the speed of the water out to sea, which essentially has a cumulative effect on the speed of an outgoing vessel, and any currents in the water could also make navigation difficult,” Mr Karatzas said.
Amy Chang Chien contributed to the research.
