Explosive charges are detonated to bring down sections of the collapsed Francis Scott Key Bridge resting on the container ship Dali on Monday in Baltimore. The FBI has launched a criminal investigation focused on the Dali, including whether the crew knew of serious system problems before setting out in the early morning darkness March 26. Mark Schiefelbein/Associated Press

The ship that knocked down Baltimore’s Francis Scott Key Bridge suffered two electrical blackouts that disabled critical equipment, federal safety investigators said in a preliminary report released Tuesday.

The report, issued by the National Transportation Safety Board, provides the first detailed examination of what went wrong as the Singapore-flagged cargo ship Dali lost power, veered off course and slammed into a critical bridge pier.

In addition to the blackouts on March 26, the report described electrical problems the day before the disaster. About 10 hours before the Dali left the Port of Baltimore for a voyage to Sri Lanka, the ship lost power twice, investigators said in the report. Officials wrote that a mistake by a crew member working on part of a diesel engine caused an initial “in-port blackout.” A second blackout in port “was related to insufficient fuel pressure,” it said.

“The NTSB is still investigating the electrical configuration following the first in-port blackout and potential impacts on the events during the accident voyage,” the report said.

The report offers a comprehensive timeline of the events leading up to and immediately after the crash.

The report described a rapid-fire series of problems before the Dali struck the bridge, though their causes remain part of the ongoing investigation.


The Dali has a main diesel engine that turns its propeller. It also has multiple auxiliary diesel engines, also called diesel generators. Those supply power to a vast array of systems throughout the ship, including steering gear, lights, and hundreds of electrical motors and pumps that are critical for the functioning of the main engine, experts said.

On the day of the collision, according to the report, a primary electrical breaker that feeds most of the ship’s equipment tripped “unexpectedly,” knocking out power to the Dali, the NTSB said. Then the ship’s main engine shut down automatically when the pumps lost power.

The Dali’s crew was able to restore power. They called for tug boats to help, and a senior pilot ordered an anchor dropped. Then, according to the NTSB, came the second blackout on the day of the crash.

A warning call went out. But soon thereafter, investigators said, the Dali hit the bridge.

According to the report, investigators plan to continue probing “oceangoing vessels’ propulsion and electrical systems; the frequency and causes of vessel contacts with bridges over navigable waters; and bridge-strike mitigation measures such as a combination of vessel-size restrictions, vessel-assist tugs, and bridge-pier protection.”

The collision killed six bridge workers, halted most trade at the Port of Baltimore and raised questions about whether federal and state authorities are prepared to prevent similar tragic disruptions in the future.


NTSB chair Jennifer Homendy said investigators have been working with technicians from Hyundai, which manufactured equipment in the engine room, to retrieve data related to the electrical failure. While investigators have been considering many things that could have caused the disaster, “we are really focused in on the electrical power system and the circuit breakers,” Homendy said last month.

The FBI has launched a criminal investigation focused on the Dali, including whether the crew knew of serious system problems before setting out in the early morning darkness March 26. Dozens of law enforcement officials boarded the Dali, which until Monday had been pinned beneath a vast section of the fallen bridge, on April 15 to search for evidence.

Attorneys representing the city of Baltimore and a local business executive have filed separate complaints in federal court in Maryland against the Dali’s owner and manager, alleging negligence before the crash.

An attorney representing the Dali’s owner, Grace Ocean Private Ltd., and its manager, Synergy Marine Pte. Ltd., both based in Singapore, did not immediately respond to a request for comment. In court, the companies have asked a federal judge to limit their liability in the tragedy to about $43.6 million.

According to information retrieved from the ship’s voice data recorder, the Dali left the Seagirt Marine Terminal in Baltimore at about 12:39 a.m. and had entered the shipping channel within about half an hour, according to NTSB investigators.

That recorder captured voices – at varying degrees of quality – from the Dali’s deck and from radio traffic. NTSB officials have been mining those recordings and interviewing key crew members to get a fuller picture of the events leading up to the collision.


At about 1:25 a.m., numerous alarms sounded on the ship’s bridge, and soon the ship’s pilot radioed tug boats in the area for help. The pilot ordered the anchor dropped and issued steering commands, then radioed that the Dali had lost all power and was heading for the bridge, according to the NTSB.

Then, at about 1:29 a.m., with the Dali moving at just under seven knots, the voice recorder captured “sounds consistent with the collision of the bridge,” according to the NTSB.

Beyond the mechanics of what failed aboard the Dali, federal marine safety investigators are also seeking to understand what may have gone wrong in the broader system meant to keep ships passing safely under critical U.S. infrastructure, an everyday occurrence that is fundamental to local economies and global commerce.

There are numerous cases when ships lose the ability to move themselves through the water. A Washington Post analysis of Coast Guard records found that hundreds of large ships have lost propulsion, many near bridges and ports. In 2021, a container ship lost propulsion for 15 minutes shortly after traveling under the Key Bridge, according to the records.

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