NTSB Preliminary Findings on the MV Dali Incident of March 2024

On 26 March 2024 the MV Dali lost power as it was leaving the Port of Baltimore. It lost both propulsion and steering. It allided with a pier of the Francis Scott Key Bridge, causing a large portion of the bridge to collapse, and killing 6 highway workers on the bridge.

"Collision" involves 2 vessels in motion. "Allision" involves a vessel underway and an stationary object. While some dictionaries list allision and allide as "obsolete," they are still used in admiralty law, and in cases like this.

Aside from a grammar lesson/vocabulary review, we have the National Transportation Safety Board (NTSB) report on that incident from March of last year. Loose Wire on Containership Dali Leads to Blackouts and Contact with Baltimore’s Francis Scott Key Bridge. Contact with extreme prejudice. Or something.

At Tuesday’s public meeting at NTSB headquarters, investigators said the loose wire in the ship’s electrical system caused a breaker to unexpectedly open -- beginning a sequence of events that led to two vessel blackouts and a loss of both propulsion and steering near the 2.37-mile-long Key Bridge on March 26, 2024. Investigators found that wire-label banding prevented the wire from being fully inserted into a terminal block spring-clamp gate, causing an inadequate connection.

The MV Dali is just shy of 300 meters long, and can carry 116,000 tons (or so) of cargo. It was traveling about 7 or 8 knots when it "contacted" the bridge.

Efforts to protect the bridge should probably have been taken, give the size of vessels on the ocean today.

Contributing to the collapse of the Key Bridge and the loss of life was the lack of countermeasures to reduce the bridge’s vulnerability to collapse due to impact by ocean-going vessels, which have only grown larger since the Key Bridge’s opening in 1977. When the Japan-flagged containership Blue Nagoya contacted the Key Bridge after losing propulsion in 1980, the 390-foot-long vessel caused only minor damage. The Dali, however, is 10 times the size of the Blue Nagoya.

There is a nice graphic at the link above showing the size difference in the 2 vessels between 1980 and 2024. And as big as MV Dali is, there are several classes of vessels that are much larger than that. Some carry more than twice as much cargo.

If you page down to the bottom of the page linked above, you will find a link to the full, 19-page report. OK, so it is not the "full report." 19 pages is not enough for that, it is a bit more than the Executive Summary, however.

A synopsis of actions taken Tuesday, including the probable cause, findings and recommendations, can be found on ntsb.gov. The complete investigation report will be released in the coming weeks.

The NTSB also has a page on their website dedicated to this incident. It has links to all of the documents from March of last year, and some links to YouTube videos, including aeral photographs of the bridge and ship post allision.

This is the What's Going on With Shipping? video NTSB Reports on the Cause of the MV Dali Hitting and Collapsing the Bridge in Baltimore. It is about a 30 minute video, and may or may not be of interest to people. It covers the meeting in which the report was presented. This was 30 minutes discussing what took place in about 4 minutes. I find Sal Mercagliano's videos fascinating. YMMV.

Container Ships 1980 to Today

Because of a conversation earlier today with a friend (you know who you are) I thought I would look up how much bigger container ships have gotten over the years. Why is it is of interest? It is because the size of ships today is quite different from what engineers were envisioning in the '70s.

First a definition. TEU is a measure of containers, it stands for Twenty-foot Equivalent Units. 20 ft containers are fairly standard in international shipping, even if most of the ones you see in the US are 40 foot - exactly the size of a semi trailer.

The Francis Scott Key Bridge over the Patapasco River in Baltimore was built in the 1970s, so the types of vessels that the engineers had in mind were (probably) at most the Panamax ships from the 1980s. These ships are in the 3,000 to 3,400 TEU range. Even if the engineers accounted for some growth is size starting with Pananmax, I don't think they would have planed for a threefold increase in size.

The MV Dali is rated at 9,971 TEUs - roughly between the C and D categories of the diagram.

Container ships continue to grow. As of January 2024 the largest ships are of MSC's Irina-class with the capacity of 24,346 TEU, or roughly two and one half times the size of the MV Dali.

You can find info on the collision of the MV Dali with the Francis Scott Key Bridge in Baltimore anywhere. For my reaction to the insanity surrounding that incident see my post MV Dali Has Become the Conspiracy Theory Du Jour.