Bridge Collapse in Baltimore

[highfigh]

I do think that will be the only solution, particularly below the water where you can't use cutting torches. Power cutters under water are slow and not really up to the job. Unfortunately there is no longer a crane big enough to lift that section of the bridge. So explosives I think are the only solution. However things could go badly wrong. I'm not sure it is a good idea to leave the crew on the ship during these explosions. I know there is risk if they are taken off. I'm sure they could be helicoptered on and off with a short turnaround time.

No underwater cutting torches?

Broco BR-22 Underwater Cutting Torch - Broco Rankin

The Industry Standard for Underwater Cutting

www.broco-rankin.com

They could use explosives underwater, too.

 

[Swerd]

I also saw this article discussing what might be built to replace the Key Bridge.

https://www.npr.org/2024/05/03/1248429399/baltimore-maryland-francis-scott-key-bridge-cable-stayed-steel-truss

 

[GO-NAD!]

The National Transportation Safety (NTSB) has issued its first report on what happened in the days and moments before the Dali crashed into the Francis Scott Key Bridge over the entrance to Baltimore's harbor. This is only a preliminary report on the known facts. Later the NTSB will issue a more thorough report on what they conclude about the causes of this disaster. These facts were in the report:

• The cargo ship had experienced two blackouts a day before the crash, while still docked.
• Two more catastrophic electrical failures occurred in the minutes before the crash. These failures triggered two critical circuit breakers to trip, stopping several pumps required for the ship's single propeller and its single rudder.
• The emergency generator was not configured to power the ship.
• The ship was under the control of an apprentice pilot, who was accompanied by a senior pilot. When the pilots boarded, the ship's captain it was in good working order.
• Crew members tested negative for drugs and alcohol.
• The ship's fuel tested negative for contaminants.
• The FBI and Coast Guard are looking into whether the crew failed to report the in-port power outage as part of a criminal investigation.

I highly doubt that fuel tampering would cause the propulsion and all four generator diesel engines to fail simultaneously. Unless they are all fed by a single fuel pump, that is. I would doubt that though. Every comment is complete conjecture right now and I've hesitated to add my own for that very reason.

Some, or all, of Dali's generators would probably have been running while they were in port, as I doubt the ship would have been on shore power. So, a fuel problem would have revealed itself earlier. If the engines all failed simultaneously (or nearly), my first suspicion would be in the electrical distribution system. All of the engines would require electrical controls and if a major fault appeared in that system, it could possibly cause all of the engines to trip. Again, this is complete conjecture and I would suggest holding off on any further speculation.

*Pats self on back*

 

[highfigh]

*Pats self on back*

• The emergency generator was not configured to power the ship.

I would think it would be sized to allow some minimal level of control.....

 

[GO-NAD!]

• The emergency generator was not configured to power the ship.

I would think it would be sized to allow some minimal level of control.....

The main diesel propulsion engine would have a direct connection to the propulsion shaft. There would have to be a clutch that could disengage the engine from the shaft, as well as connect the emergency generator to the shaft. The generator engine would have to be sized to not only provide emergency electrical power, it would have to be large enough to propel the ship. This just isn't a practical proposition.

 

[highfigh]

The main diesel propulsion engine would have a direct connection to the propulsion shaft. There would have to be a clutch that could disengage the engine from the shaft, as well as connect the emergency generator to the shaft. The generator engine would have to be sized to not only provide emergency electrical power, it would have to be large enough to propel the ship. This just isn't a practical proposition.

It has a bow thruster but without backup, that's obviously not usable. By minimum basic control, I didn't mean 'propulsion' to mean 'somewhat close to normal'.

Hopefully, this incident will cause changes to be made.

 

[GO-NAD!]

It has a bow thruster but without backup, that's obviously not usable. By minimum basic control, I didn't mean 'propulsion' to mean 'somewhat close to normal'.

Hopefully, this incident will cause changes to be made.

To avoid the collision, she would have needed some sort of propulsion. If changes are needed, it may be as simple as requiring tugs attached until clear of any obstructions.

 

[lovinthehd]

Some follow up after blowing some of the bridge off of the Dali

 

[TLS Guy]

No underwater cutting torches?

Broco BR-22 Underwater Cutting Torch - Broco Rankin

The Industry Standard for Underwater Cutting

www.broco-rankin.com

They could use explosives underwater, too.

I can't imagine that underwater cutting torch is very effective. The water would conduct the heat away fast and it would make really slow progress. Explosives can be used under water, but the shock wave is more intense and travels much further. So the damage radius is greatly increased.

Once the ship is out of the way, I do expect some underwater explosives will be used.

 

[TLS Guy]

*Pats self on back*

Actually sub standard bunker fuel is currently a problem currently. Fortunately most of the failures have been out at sea. But ships have had to be rescued.

 

[TLS Guy]

To avoid the collision, she would have needed some sort of propulsion. If changes are needed, it may be as simple as requiring tugs attached until clear of any obstructions.

The changes are much greater readiness to declare ships unseaworthy. It now appears that ship had multiple electrical failures while in port, and was clearly not in seaworthy condition.

Tugs will help, but tugs do not have nearly enough power to completely control a ship that size. So, even with tugs, total failure of the ships propulsion might not have prevented that accident.

 

[GO-NAD!]

The changes are much greater readiness to declare ships unseaworthy. It now appears that ship had multiple electrical failures while in port, and was clearly not in seaworthy condition.

Tugs will help, but tugs do not have nearly enough power to completely control a ship that size. So, even with tugs, total failure of the ships propulsion might not have prevented that accident.

I get that, but once underway, there isn't a whole lot more that can be changed. As for the electrical problems, it's difficult to say right now what level of oversight would have been required in order to uncover them before she sailed. The investigation is still ongoing, so it's a bit premature to suggest what changes might be in order.

 

[GO-NAD!]

Actually sub standard bunker fuel is currently a problem currently. Fortunately most of the failures have been out at sea. But ships have had to be rescued.

But, not in this case. Everything failing, all at once, was a pretty strong indicator to me of electrical issues, which is why I suggested it.

 

[highfigh]

I can't imagine that underwater cutting torch is very effective. The water would conduct the heat away fast and it would make really slow progress. Explosives can be used under water, but the shock wave is more intense and travels much further. So the damage radius is greatly increased.

Once the ship is out of the way, I do expect some underwater explosives will be used.

How would underwater ship salvage operations happen if cutting torches don't work?

If you didn't click on the link, you missed "The Broco BR-22 Underwater Cutting Torch and Broco Exothermic Electrodes are featured in the U.S. Navy Underwater Cutting & Welding Manual".

Don't assume.

Are you familiar with shaped charges? They impact the area where they need to cut, but not in 360°.

 

[TLS Guy]

How would underwater ship salvage operations happen if cutting torches don't work?

If you didn't click on the link, you missed "The Broco BR-22 Underwater Cutting Torch and Broco Exothermic Electrodes are featured in the U.S. Navy Underwater Cutting & Welding Manual".

Don't assume.

Are you familiar with shaped charges? They impact the area where they need to cut, but not in 360°.

I did look at it. It does not sound highly practical to me, and clearly hazardous to the operator. I doubt there are many skilled enough to do this and it would be very slow going.

My guess is that they will craned out the remnants they can, and use controlled depth charges to make all remnants able to be craned out.

 

[Swerd]

I remember seeing a Coast Guard spokesman saying that underwater cutting torches would be very slow, at best, to cut the steel beams of the bridge. And they would require water clear enough to allow the work to be visible to the divers. The Patabsco River, is muddy this spring. Visibility is less than one foot. That's why they have those big cranes.

 

[Swerd]

We've heard plenty about the Key Bridge's demise; how the MV Dali lost it's power at the worst possible time; and how the Key Bridge's design was inadequate. Today, I saw this article in The Washington Post that addressed the question of why no improved protection of the bridge's support towers were built.
Long before Key Bridge collapse, Baltimore mariners warned of ‘ship strikes’

To summarize briefly, the article mentions improving the poorly protected support towers were mentioned as far back as 2004 (possibly earlier) in meetings of the Maryland Transport Authority (MdTA), the operator of this bridge. It remained an action item in MdTA minutes for years before it disappeared in 2016, without explanation.

An obvious reason why better protection (dolphins) for the old bridge was never built, was cost. In hindsight that was a bad idea. Recent construction of dolphins around bridge supports for the Delaware Memorial Bridge (see photos below) cost about $93 million. A new replacement for the Key Bridge is estimated to cost nearly $2 billion. Some quick arithmetic (93 ÷ 2000) shows dolphins might cost 4.7% of the price to build a new bridge.

The Delaware Memorial Bridge, a twin span suspension bridge was first built as a single bridge in 1950, with a twin built in 1968 – about the same time as Baltimore's Key Bridge.

Delaware Memorial Bridge gets a $93 million upgrade to protect against ship collision

As part of the new bridge ship collision safety system, eight 80-foot-diameter stone cylinders and four cells will be constructed at the piers supporting both sides of the towers, at a minimum of 443 feet from the edge of the 800-foot-wide Delaware River channel.

Proposed new dolphins

Compare those dolphins with the greater protection built for the newer Sunshine Highway Bridge over Tampa Bay.