The Dali Is a Big Ship. But Not the Biggest.

Note: Widths shown are for the widest point for each ship. One T.E.U., or 20-foot equivalent unit, represents the volume of one 20-foot container, though ships can carry containers of varying sizes.

The container ship that hit the Francis Scott Key Bridge early Tuesday while leaving Baltimore Harbor is enormous. When fully loaded, the vessel, the Dali, can weigh more than 116,000 tons and carry thousands of containers of cargo.

But in comparison with some of the other ships out there, the Dali is a featherweight. The size of the largest container ships has grown, in fits and starts, since the early 1980s. The current largest class of container ships in the world can hold more than twice the amount of cargo that the Dali can.

Container Ships Keep Getting Bigger

Source: "Port Economics, Management and Policy," by Theo Notteboom, Athanasios Pallis and Jean-Paul Rodrigue

Note: One T.E.U., or 20-foot equivalent unit, represents the volume of one 20-foot container, though ships can carry containers of varying sizes.

Giant ships have played a central role in the fueling of the modern economy, as global demand for electronics, clothes and other consumer goods continues to grow.

For shipping lines, the bigger the ship, the more cost efficient each voyage becomes.

The rise of massive ships has in turn pressured ports to adapt in order to attract business. For example, when an expansion of the Panama Canal in 2016 allowed larger ships to pass through, major Eastern Seaboard ports reacted by investing billions of dollars, said Jean-Paul Rodrigue, a professor in the department of maritime business administration at Texas A&M University-Galveston.

The ports, including Baltimore, scrambled "to dredge, to expand the infrastructure, to buy new cranes to accommodate these ships," he said.

In August, the Ever Max, which is over 1,200 feet long and can hold up to 15,432 20-foot containers, became the largest container ship to ever enter the port of Baltimore.

Container ships are only one kind of common commercial vessel, however. Bulk ships and tankers have been on the bigger side for decades, and carry wet and dry goods that include oil and coal — a major export for the Baltimore port. In the 1970s, the decade that the Francis Scott Key Bridge was built, tankers roughly the same breadth and length as the Dali were in use in Eastern U.S. ports.

Bigger ships can create bigger disasters when accidents happen. Size played a role when a 1,300-foot vessel got stuck in the Suez Canal in 2021, causing alarming shipping delays.

The Dali's size was not necessarily a factor in Tuesday's accident, and investigators continue to search for sources of the cause. Even for a ship half the Dali's size, Mr. Rodrigue said, "I suspect the outcome would've been the same."