UPDATES
April 11, 2024 - Possible point of contact of Dali with bridge noted.
April 2, 2024 - Added time last vehicle clearing bridge
Following is an annotated timeline of the cargo ship Dali’s last trip. Dali, carrying 4,700 containers, left its berth near the city of Baltimore but lost power soon thereafter and crashed into the Francis Scott Key Bridge on its way out to the open sea.
The timeline is constructed from videos, reports and expert commentary on YouTube.
This timeline is intended to help with future articles, here and elsewhere, that will make use of the information provided, such as time, position and velocity, for first-order analyses, like acceleration, forces and energy, to help us understand what happened and how to prevent it from occurring in the future.
The official investigation is underway by the National Transportation Safety Board (NTSB) and is expected to conclude in “6 to 12 months.”
All time is local (U.S. Eastern Daylight Time, GMT-4) and all events occurred in the early hours of Tuesday, March 26, 2024.
00:39 Dali sails from Baltimore’s Seagirt Marine Terminal accompanied by tugboats. On board are 21 Indian crewmembers, 2 harbor pilots, 56 hazmat containers and 4,700 standard shipping containers.
01:07 Dali enters the Fort McHenry Channel, the main shipping channel in the Patapsco River that will go under the Francis Scott Key Bridge. The tugboats are released.
01:24 Dali is up to eight knots with a heading of 141 degrees.
01:24:33 Dali loses power. The ship goes dark and quiet.
01:24:59 Multiple alarms sound. The voyage data recorder (VDR) stops recording electronic data, but with its backup power source, keeps recording audio from the bridge, including the pilot’s verbal rudder and steering commands. While rudder commands are issued, replies from the crew confirming commands were followed, as is customary, are not heard.
01:25:31 Power comes on as indicated by floodlights from a shore camera. For 58 seconds, the ship had no power. Emergency diesel generators are supposed to provide power within 45 seconds of an outage, according to Sal Mercogliano, former maritime mariner and owner of What’s Going on With Shipping YouTube channel. The emergency engine, about the size of a truck engine, has only enough power for some of the ship’s systems. Bow thrusters are beyond the means of an emergency generator. Judging from the pilot’s subsequent actions and the ship’s path, it is doubtful that the Dali’s rudder could be controlled with emergency power
1:25:40 Thick plumes of black smoke, indicative of main diesel engines being restarted, can be observed coming out of the smokestack in the video.
01:26:02 The VDR resumes recording the ship’s electronic data. Rudder and steering commands can still be heard.
01:26:07 The first indication given by MarineTraffic.com that the Dali is changing its course, from 141 degrees to 142.9 and slowing down (to 8.5 knots). Source: MarineTraffic.com. The ship could have been turning anywhere from within seconds of 1:25:31, when the ship‘s power was restored, to this record.
01:26:37 The ship’s power goes off for the second time.
01:26:39 Pilot issues general VHF call for tug assistance to any tugs in the area. This is the first distress call from Dali.
01: 27:04 Pilot orders the crew to drop the port (left) anchor to stop the ship from turning toward the starboard (right) side and is still issuing steering commands but perhaps in vain, as his ship is without power to its propulsion and steering systems. Anchors are meant to hold a ship stationary and would have little effect on a ship still moving at speed, according to Mercogliano.
01:27:10 Power is restored for the second time.
1:28:18 Dali has slowed down to 6.5 knots.
01:27:25 Pilot issues a Mayday with a general radio call over VHF saying that Dali had lost all power and was heading toward the Key Bridge tower.
1:27:53 Maryland Transportation Authority (MDTA) duty officer dispatches units to close the bridge.
01:28:27 Dali has increased its speed to 6.7 knots. Speeding up may be a desperate attempt to turn the ship faster to avoid the bridge tower.
01:28:09 Last two vehicles going South clear the span to the south of the tower. It is 39 seconds before Dali strikes the bridge.
01:28:30 Dali is observed to be gradually swinging to the left. But it will be too little, too late. The ship is half a ship length away from the bridge, estimates Mercogliano.
01:28:43 Spray at waterline near the tower starts to appear. This could be Dali's bow wave against the bridge towers or the island the bridge towers are on.
01:28:49 Bridge deflection is observable in a video. Dali is still moving at 6.8 knots, according to AIS data shown in MarineTraffic.com. The bridge is is collapsing.
01:29:00 First sound of collision with the bridge is recorded on the VDR. Sounds will continue to 01:29:33 as the bridge tears into the ship, and vice versa, and containers loaded on the ship’s foredeck fall.
01:29:27 Speed is recorded as 2.2 knots as Dali, now has the bridge draped over her. The bridge structure is acting like a net, straining to stop the ship.
1:29:00 to 01:29:33: Sounds of havoc on the foredeck continue to be recorded by the VDR, according to NTSB which released a transcript but not the audio. We can only imagine the volume from the deck collapsing, the steel being deformed and fracturing, and containers being displaced and falling.
Sources
Official Footage of the Francis Scott Key Bridge Collapse, StreamTime Live, YouTube.
Salvatore Mercogliano, maritime historian, former maritime mariner and owner of What’s Going on With Shipping YouTube channel.
NTSB Media Briefing 2 - Francis Scott Key Bridge struck by Cargo Ship Dali, YouTube, March 28, 2024.
MarineTraffic.com