Baltimore Bridge Collapse: Analysis of MV Dali's Collision Course

Footage of the bridge collapse is here: https://www.youtube.com/watch?v=mULzspJZuf8 The owner of this footage has restricted it from circulation without permission which is why I have not used it in this video! If anybody is more familiar with the Chesapeake Bay area and shipping involved there you might be able to comment a bit more on protocols surrounding tug use. My understanding is Dali had tugs leaving her berth and executing the turn into the channel but it seems they left her once they finished the turn. Thanks to other commenters for pointing out the similarities with other bridge-ship 'allisions'; 1975 Tasman Bridge: en.wikipedia.org/wiki/Tasman_Bridge_disaster 1980 Skyway Bridge: en.wikipedia.org/wiki/Sunshine_Skyway_Bridge#1980_…

The problem with this incident is that it happened at the worst possible time. When a ship like this is leaving a port like this, in quite confined conditions, the ship will carry one or several local harbor pilots. In this case, the ship had two local harbor pilots on board. When a ship navigates through a pretty confined area like this, there will usually be more generation power online (Diesel generators) than normally needed and the control room will be manned. What people need to understand is that if a ship suffers a blackout, all power to the main switchboard is lost which means that all the equipment needed to operate the main propulsion engine is lost which trips out the engine. At the time the ship suffers the blackout, the steering gear (rudder) will be left in the position it was in when the blackout happened. This means that the ship will continue in the direction of the rudder position bleeding off the speed it had at the time of the blackout. The next thing that will happen fairly quickly (within a minute or less) is that the emergency Diesel generator will start automatically and power up the emergency switchboard. From the emergency switchboard, the ship will now have power for essential system such as navigation systems, lighting (not full lighting), steering gear power and a few auxiliaries to enable startup of the main Diesel generator engines again. In order to restart the main engine, compressed start air, fuel systems, lubrication systems and cooling water systems are needed. In an extreme emergency, it is possible to start the main engine shortly with reduced systems online but this may subject the main propulsion engine to severe damage. In any case, to get the main Diesel generators and the main propulsion engine started up again after a blackout will take some time. Even if everything goes well and all the crew know exactly what to do, this process can easily take 5-10 minutes in the very best circumstance and usually longer. The problem is that whatever caused the blackout in the first place may still be a fault that prevent the startup process to take place. Suffering a blackout on board any large ship in any kind of confined spaces is the worst nightmare for any professional seaman. However, it is important to always understand that when suffering a blackout, the main switchboard that powers main essential services will be gone and you are left with the required minimum services the emergency switchboard can provide and that will usually not include the service of the main seawater cooling pumps which will be needed if you want to be able to operate the main propulsion engine more than a few minutes. All the Diesel engines on board are cooled by closed fresh water systems and the fresh water is cooled in heat exchangers by seawater so if any of the Diesel engines (except the emergency Diesel engine) are to be operated for a longer time (more than a few minutes), the main seawater cooling pumps are needed and they are too big to be operated by the emergency Diesel generator. It's way too early to know what initiated the blackout. There are literally hundreds of reasons this can happen, but since all power was lost, it could be a short circuit in the main switchboard bus or a major malfunction of one or two of the main Diesel generators which would have left the ship with too little generation power on the remaining Diesel generator which could then cause the blackout. However, an investigation must find out what happened because it is extremely rare to see this kind of total blackout. Usually, a ship will have a power management system that may automatically disconnect faulty parts of the switchboards and/or generators thus enabling the ship to at least operate on reduced power. Regarding a crash stop and reversing the main propulsion engine, there are a few limitation there. If the ship is moving forward in the water with sufficient speed when the blackout happens, the propeller and thus main engine will continue to rotate in the direction of moving forward. Even when you have the power back, it may not be a simple thing to carry out a reverse operation of the main engine since this can first really be successful after it has been possible to stop the forward rotation movement of the propeller shaft and engine crankshaft. This type of ship has a propeller shaft that is directly connected to the main propulsion engine. There is no gear in between so in order to start the main engine in a reverse direction, the crankshaft and thus the propeller shaft shall basically be stopped first. The first light coming on seems to be the emergency generator having started up. The next flickering of light may either be an attempt to power up the main switchboard again with one of the main Diesel generators and the black smoke coming out of the funnel is either because the main Diesel generators are loaded up very suddenly or because the main engine is attempted started up. These are Diesel generators so when you start a Diesel engine of these sizes and load them up too quickly, there will be plenty of black smoke coming out of the funnel simply because the engines will not get enough combustion air because the turbochargers have not had time to spin up sufficiently yet. A long comment, which could be much longer if being more detailed and technical so I hope people will excuse the long comment.

Baltimore native here. My mom was set to drive over that bridge the morning after it fell, as a matter of fact. And I was going to drive over it to see family on Easter Sunday. Some additions to the info you gave: The ship is confirmed to have dropped anchor in an attempt to miss the pillar of the bridge. The ship sent out a mayday call shortly before collision, and the transportation authorities were able to stop incoming traffic onto the bridge. The confirmed number of people on the bridge was 8 (2 have been accounted for- the rest are considered dead) they were all road workers filling potholes. I really can’t overstate how important this bridge was. It shortened commutes significantly, but it was a large part of Baltimore’s identity too. 35,000 people commuted over the bridge every day. Everyone I’ve talked to about it is in total shock that it’s gone- it’s like we’ve lost a family member. Thankfully, there is a tunnel under our port for commuters to use. But now it’s going to be overloaded, so there are concerns about that too. Just thought I’d add that in. I was surprised to see a channel I’ve followed for a while cover this disaster in my state!

I live in Baltimore County. Seeing all the conspiracy theories and claims that the bridge wasn't well maintained is very tiring. Thank you for covering this in a sane way (I expected nothing less, of course).

I live in St. Petersburg, Florida. In 1980 this very thing happened to our Skyway Bridge when a freighter took down the southbound span killing 35 people mostly in the Greyhound bus that when into the bay. It's something that has been on our minds ever since, and we mark the day it happened every year. When they built the New Skyway they installed all these dolphins to protect the support columns and also for the main supports they made two islands. I noticed that the Key bridge only had two dolphins way back from the bridge, it left the support exposed to any wayward ship. I don't understand why, after it happened before with the Skyway bridge, they didn't install better protection around all the important bridges.

The only channel I trust to cover disasters like this.

For those who don't know, Baltimore harbor is historic. During the War of 1812 (between England and US), an American lawyer was on a British ship that was at anchor in the harbor. He watched the British shelling of Fort McKinley, which was on an island in the harbor. The morning after the shelling, he was shocked to see the American flag still flying over the fort, and he was inspired to write a poem about it. His name was Francis Scott Key, and his poem went on to become the words to the American National Anthem.

That the police managed to stop traffic in less than 5 minutes once the ship lost control and sent a Mayday, then relayed to them was amazing. Yes it was 1: 30 AM , but I commend the police/dispatchers/port authority/ship's crew involved for quickly reacting saving many lives. So far ,there are only 6 dead from a bridge maintenance crew and the vehicles lost were their vehicles. You can see 3-4 stopped/parked vehicles with yellow flashing lights on the bridge before the collapse. I assume these were vehicles of the maintenance crew. No civilians vehicles/people seem to has been lost. Really miraculous given the scale of the disaster.

You've done the best job of pronouncing 'Maryland' out of all the foreigners I've seen pronounce it over the last few days.

A couple of points for non-Americans: I-95 is the major highway that runs from southern Florida through all of the populated East Coast cities up all the way to Canada. I-695 is a loop that goes around Baltimore rather than going through the city center. Therefore anyone going north from Florida / Washington or south from New York, Boston, or Philadelphia would go over this bridge [Edit: if they want to avoid local traffic or if their vehicle does not meet more restrictive size and weight and content limitations of other routes or if they are headded towards the industrial regions around 695]. Francis Scott Key, FWIW, wrote the national anthem while watching the British attack Baltimore during the War of 1812.

According to the excellent "what's going on with shipping" analysis, tugs in Baltimore typically assist ships out of port, but return to base well before the bridge. Dali was escorted in that manner, with the tugs departing before the ship entered the field of view of the webcam.

Having driven over this bridge many times, I never even considered the possibility of this happening.

I am so, so grateful you prepared this video so quickly. I have sent it to a number of friends to explain what happened. If I may, the bridge was built in the 1970s and was a marvel for its age. It really consists of two parts. There are two causeways on each side of the truss bridge, held up by modest, but closely placed, piers. The causeway is self-supporting and does not have a superstructure much above the road surface. In the middle is the truss span. The truss starts at one of the causeway piers, connects to a large massive pier, connects to another duplicate large, massive pier, and connects to a causeway pier on the other side. The ship was trying to pass between the two large piers, where the truss bridge was significantly higher above the water and far more open than the causeway portion. Those two large truss piers were protected by what amounts to large bollards. However, they were designed for the ships with half or less the mass of the Dali. They failed to provide the necessary protection for today's much larger ships. That is the main point of failure (to make the analogy popular on your channel), if the bollards were of proper strength, height, and number, they would have stopped the Dali from hitting the pier with such destructive force, just as if the water tight compartments of the Titanic had gone all the way to the superstructure, they would have kept the water from spilling over the subsequent compartments, sinking the ship as quickly as occurred. I completely agree with you about the tugs. I am absolutely sure they will be required after the harbor reopens. Another example of the rules not being updated with the increasingly large ships, just as the Board of Trade regulations stopped at 10,000 registered tons for lifeboat requirements for the Titanic.

I am a lifelong resident of MD. I live about 65 miles west of Baltimore. I have traveled this bridge and others that go from the west side to Maryland’s eastern shore my entire life. Just two days ago our son showed us your channel and then this accident happened. I truly appreciate your knowledgeable insight and your other informative, fascinating videos. Thank you!

Such a horrible thing to happen. My heart goes out to families who have lost loved ones or are dealing with injuries. So sad.

Wow. Analysis without conspiracies - refreshing!

Great analysis and runthrough! The "Casual Navigation" channel pointed out that the side channel that meets up with the main shipping lane just before the bridge, would affect the currents, potentially pulling the ship towards the pylon, despite the rudder staying straight ahead, so if all control went offline, it's possible that the natural progression of the vessel would be straight into the bridge pier.

Thank you for covering this. I live in the DC-Baltimore area and it’s surreal to see the footage of a bridge I use frequently tumbling down. P.S., Yes, NTSB will head up the investigation. The focus thus far has been search and rescue—sonar revealed that there are indeed cars in the water. FYI: the Key Bridge was the world’s third longest truss bridge.

Thing is this has essentially closed a major harbour, and also stopped traffic flow for the entire area as well. Going to mean a massive delay all over the world, as ships that were contracted to leave do not, and cargo going in has to divert and wait at other ports, then get shipped by rail or road to destination.

I live 30 min from Baltimore and worked in the city until February. As soon as I heard about this I thought "I wonder if Mike will make a video about this?" So glad that you did so I can get a comprehensive analysis of what happened!