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Baltimore Bridge collapse after ship collision
102

Baltimore Bridge collapse after ship collision

RE: Baltimore Bridge collapse after ship collision

Really crazy. Possibly avoided a major catastrophe since it happened at 1.30 AM and not during peak hour. Apparently ~7 people missing. (Edit: up to 20 people?)

RE: Baltimore Bridge collapse after ship collision

The full video shows the ship suddenly turning to starboard and all of its lights going dark and coming on again multiple times right before the collision. Very strange. Hope they manage to rescue as many as possible.

RE: Baltimore Bridge collapse after ship collision

Form what I could see off the video it looks like the ship hit the tower and basically lifted the structure off the supports causing instant global collapse. Ack in t h e 1970s you wonder what sort of hazards were considered and how to stop ships crashing into the bridge. There are some big buoys or may e stations visible but not enough clearly.

The boat had pilots, was in good weather so sudden power loss? Rudder failure?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Baltimore Bridge collapse after ship collision

As @goldgelb said, the ship lights go off a few minutes and a few seconds before the collision.

It's been a while since I looked at ship impact but there's not much you can realistically do to stop a container ship impact directly, so it needs to be in the right place or headed off much earlier.

RE: Baltimore Bridge collapse after ship collision

Maybe it's me, but this design looks to be particularly susceptible to collapse in the event of a collision with what appears to be gravity based resting supports onto the concrete pier. A full steel structure going down into the caissons would have given some resistance?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Baltimore Bridge collapse after ship collision

Tragedy for those who lost their live or their loved ones.

But amazingly fortuitous that the bridge was so empty at the time. Even minutes earlier it seemed much busier.

RE: Baltimore Bridge collapse after ship collision

The lights going out on the ship prior to the collision might suggest there was some kind of power issue leading to loss of steering and/or thrust? Maybe they were just passengers for a good few minutes before the crash.

RE: Baltimore Bridge collapse after ship collision

tragic. I suspect that part of the discussion touch on the relative size and mass of container ships now versus 50 years ago.

RE: Baltimore Bridge collapse after ship collision

It looks like the entire port of Baltimore is now cut off from shipping in both directions. This could have adverse implications for months to come.

Brad Waybright

The more you know, the more you know you don't know.

RE: Baltimore Bridge collapse after ship collision

@bugbus The smoke billowing from the chimney right after the lights come back on the first time (that can be seen in the video) would seem to support that. If the steering could be affected even after power is seemingly regained, I don't know. I assume the ship only has one screw and that inadvertent differential thrust is not the reason.

RE: Baltimore Bridge collapse after ship collision

A sad day, indeed. From the looks of it, several of the vehicles were likely maintenance workers. Looks like several of them had flashing yellow lights and were not moving.

Quote (thebard3)

It looks like the entire port of Baltimore is now cut off from shipping in both directions.

As much as I hate the traffic, it makes me thankful for the tunnels we have here in Norfolk/Virginia Beach.

I can only find a video that starts a couple seconds before the strike - not seeing the apparent power failure (at least one bright spotlight is visible forward and then gets subsequently crushed by the collapse).

RE: Baltimore Bridge collapse after ship collision

Quote (phamENG)

I can only find a video that starts a couple seconds before the strike - not seeing the apparent power failure (at least one bright spotlight is visible forward and then gets subsequently crushed by the collapse).

Third post in this thread has a link to the full video

RE: Baltimore Bridge collapse after ship collision

Ah. Thanks. Missed that.

RE: Baltimore Bridge collapse after ship collision


After the impact one pier remains the other was demolished.


The demolished pier does not seem to be able to withstand an impact by a containership. This looks like an under-design. If that is the case the bridge could have been protected by installed extra stronger piers before and after the weak pier to withstand the containship impact.

RE: Baltimore Bridge collapse after ship collision

The bow reached over the pier and took out the support. Same as when a ship gets sideways at the dock and the bow takes out cranes. The bridge likely would have survived if the ship behind the bow had side swiped the pier.

RE: Baltimore Bridge collapse after ship collision

Question: Does Baltimore use Harbor Pilots ?
ALSO, Knowing that probability that a given harm may occur is Low but its severity is High... are Tugboats ever used to assist with large vessels maneuvering though and near important infrastructure? If not, should they? Do other ports do so?

RE: Baltimore Bridge collapse after ship collision

Yes, and two pilots were onboard.

RE: Baltimore Bridge collapse after ship collision

3
The ship going completely dark twice means she lost power and was unable to effectively bring it back. She would have had no rudder or thrusters while carrying both a full cargo and presumably heavy fuel load. Meaning she was deep in the water, most susceptible to any kind of current, with no control and massive forward inertia. The question to answer is why the power loss, which I can't begin to guess at right now.

edit:

The container ship, Dali, had been inspected 27 times since its building in 2015, and had two “deficiencies" since then, according to records from the Electronic Quality Shipping Information System (Equasis).

In June of 2023, in San Antonio, Chile, the Chilean authorities gave the Dali a “deficiency” for “propulsion and auxiliary machinery — gauges, thermometers, etc,” according to Equasis records. And, in November of 2016, in Antwerp, Belgium, the Dali was given another “deficiency” for "structural conditions” described as “hull damage impairing seaworthiness," due to it being holed, Equasis records show.

Dali was involved in an incident in 2016 in the Port of Antwerp, port officials confirmed to CNN.

The last inspection the Dali had was on September 9, 2023, when it inspected by the United States Coast Guard in New York, New York, Equasis reports. No deficiencies were noted from that inspection, according to the database.

RE: Baltimore Bridge collapse after ship collision

From gCaptain, about the tugboats:

Quote:

According to Marine Traffic the ship departed the Seagirt Marine Terminal in the Port of Baltimore at approximately 00:30 local time, sailed northwest past the Nuclear Ship Savanah then turned southeast to depart the harbor, released the tugboats, and collided with the bridge at approximately 01:38.

Full article: https://gcaptain.com/ship-lost-control-before-hitt...

Forum members say many harbors require tugs until the ships are past the bridges.

RE: Baltimore Bridge collapse after ship collision

I'm surprised not to see a bumper system around the piers given the traffic under it. The power-line towers before the bridge look better protected.

RE: Baltimore Bridge collapse after ship collision


This photo depicts the deck was sinking in a straight line over the demolished pier. This is important as it could only occur if the pier was pushed away or knocked out underneath the bearings. Thus the pier structure has almost zero resistance against such impact. After the collapse the bridge and the broken concrete columns all resting on top of the bow of the container ship.

RE: Baltimore Bridge collapse after ship collision

There are a few reasons they might not have used tugs. My guess is the bridge has a narrow navigable channel based on the after collapse photos showing the bridge pieces sitting on the bottom. That's no more than speculation though.

RE: Baltimore Bridge collapse after ship collision

Some basic information: "The Francis Scott Key Bridge, known originally as the Outer Harbor Crossing until it was renamed in 1976, while still under construction, or simply as the Key Bridge or Beltway Bridge, was a steel arch continuous through truss bridge spanning the lower Patapsco River and outer Baltimore Harbor / Port carrying Maryland Route 695 in Baltimore, Maryland, United States. The main span of 1,200 feet (366 m) was the third longest span of any continuous truss in the world.[2] It was the second-longest bridge in the Baltimore metropolitan area, after the Chesapeake Bay Bridge."

Steel was expensive in the 1970s and interest rates were high. I'm sure budgets were stretched to even build this continuous truss bridge. Not an excuse, but redundancy was not a prime consideration in bridge design in the 70s. In any event, this was not a case of a single member failure leading to progressive collapse.

RE: Baltimore Bridge collapse after ship collision

According to Wikipedia it was initially supposed to be a tunnel but was too expensive.

Quote (Wikipedia)

Bids for constructing the proposed Outer Harbor Tunnel were opened in July 1970, but price proposals were substantially higher than the engineering estimates.[11] Officials drafted alternative plans, including a four-lane bridge, which the General Assembly approved in April 1971.[12][13]

At an estimated cost of $110 million, the bridge would have more traffic lanes and lower operating and maintenance costs than a tunnel.[citation needed] A bridge would provide a route across the Baltimore Harbor for vehicles transporting hazardous materials, which are prohibited from both the Baltimore Harbor and Fort McHenry tunnels.[14] The United States Coast Guard issued its bridge permit in June 1972, replacing an earlier approval of the tunnel from the Army Corps of Engineers.[10] Construction of the Outer Harbor Bridge began in 1972,[15] several years behind schedule and $33 million over budget.[16]

https://en.wikipedia.org/wiki/Francis_Scott_Key_Br...)

RE: Baltimore Bridge collapse after ship collision

Ship size and mass has increased tremendously in the last few decades. Perhaps this will trigger a re-evaluation of all bridges and protections. For example, even if substantial pilings are used, if the overhang of the ships increases enough they can still reach the primary bridge structure. Likewise if the height and width of cargo is high enough they can still reach areas of the bridge previously thought safe.

RE: Baltimore Bridge collapse after ship collision

In the video, a short while after the lights come back on the first time, there is a smoke plume out of the ship's stack, and it continues right up to the strike. I suspect the engine stopped, causing the lights to go out. Then it was restarted, with the plume signifying it had not settled down to a proper running state yet. The second "lights out" is also of interest--did the engine stop again? Was there another restart?

The opening under the bridge is about 1114 feet wide. The ship is about 157 feet wide. The normal route under the San Francisco Bay bridge is 2171 feet wide. In 2007, a container ship hit one of the piers, with no significant damage to the bridge or its supports.

Strikes me that the bridge fenders on the Baltimore bridge were inadequate (as mentioned by others). And the ship got a "lucky" strike, being almost headlong. I also think the clear span of the Baltimore bridge is pretty skimpy, but real bridge folks likely know more than I about it.

The NTSB will issue a report in a year or two, and it will likely be pretty good. Ship has massive failure(s) at exactly the wrong time and hits an inadequately protected bridge.


spsalso

RE: Baltimore Bridge collapse after ship collision

I'm not sure how reply directly to someone. But Spsalso's comment the first time the lights went off the main powerplant went. When the lights kicked back on it was the backup system. Then the second time the lights went off it was the backup power switching back over to main power, hence the plume. Backup power does not provide power to thrusters. Usually only rudder, navigation, and emergency systems.

RE: Baltimore Bridge collapse after ship collision

But the plume started before the second time the lights went off.

The lights came back on, the first time, at 2:23

The smoke plume started at 2:35

The lights went off the second time at 3:29

The plume was emitted until impact, or thereabouts.


By the way, Sal's doing his usual great job of covering this event:

https://www.youtube.com/results?search_query=what%...


spsalso

RE: Baltimore Bridge collapse after ship collision

Right but the backup power stays on until the main power is up and ready.

The sequence is typically

Power goes out - backup automatically kicks in - crew attempts to restart main - main fires back up - crew checks to make sure its holding - crew manually turns off the backup and makes the switch.

RE: Baltimore Bridge collapse after ship collision

Found a drawing of the bridge fender design.



There is a report which analysed the impact resistance of the bridge which I've not been able to find.

Quote (Knott, M.A. and Larsen, 0. Damgaard)

Guide Specification and Commentary for Vessel Collision Design of Highway Bridges”, US Department of Transportation, Federal Highway Administration, Publ. No. FHWA-RD-9 1-006, Dec. 1990

RE: Baltimore Bridge collapse after ship collision

Looks like it just missed a dolphin:



After the Sunshine Skyway Bridge disaster they went all out on the protective dolphins on the new span:

RE: Baltimore Bridge collapse after ship collision



Here's a good photo from the BBC.



And one from CNN.

RE: Baltimore Bridge collapse after ship collision

3
Lots of smoke and brownout indicates a failing service generator set. The failing unit should have tripped on reverse power and then automatic load shedding should have taken care of the rest. Maybe it's power output was significantly reduced but never went below zero. Perhaps they were trying to bring an additional unit online instead of tripping the failed unit to avoid the hassle of restoring the plant after load shedding.

The safest option could have been tripping all generators and letting the emergency diesel so it's thing. This would have restored steering and engine power within 30 seconds. However, it is a lot of work to bring the plant back to normal after this.

As for tugs, there isn't much we can do if the ship is going more than 6 knots. It takes all of our horsepower to keep up and we don't have any left for maneuvering.

RE: Baltimore Bridge collapse after ship collision

Ship tracking showed 8.5kn when the power failed and slowing to 7.5kn just before impact. There are not many structures that could withstand that kind of direct impact.

RE: Baltimore Bridge collapse after ship collision

This marine traffic video shows the location of the tugs after leaving the Dali. It appears that no attempt is made to reach the ship until just moments before impact. This implies no mayday call was made until late in the process.

Link

RE: Baltimore Bridge collapse after ship collision



Close up shot

RE: Baltimore Bridge collapse after ship collision

I regret even bringing this up, but could the power failure be due to a cyber attack? Hope the authorities are recovering and analyzing the software logs.

RE: Baltimore Bridge collapse after ship collision

This same ship had already destroyed a dock in 2016, in Antwerp!

Link

RE: Baltimore Bridge collapse after ship collision

11
Pretty sure piers are NOT designed for a fully loaded container ship to impact them, regardless of speed. Let's be more judicious on the whole "defective design" folks. Find a referenced standard and know what you're talking about, please.

As a side note, if that Sunshine Skyway is the bridge in Tampa bay that fell due to a "tug impact" that tug impact was during a Hurricane. They blamed the pilot for a long long time until he finally prevailed.

RE: Baltimore Bridge collapse after ship collision

Watching the Full Video from the 3rd post, I think the fatal error came after they regained electrical power the first time.
Two things to watch is that there was no smoke before the power outage and the ship appeared to be moving in a straight line.
The heavy black smoke didn't appear until a few seconds after power was first restored.
I think that when they regained control of the main engine, they put the drive in reverse and gave it full throttle.
This is a single propeller ship.
Besides the forward and reverse thrust there is a side force that come off of the propeller that pushes the stern to the side.
If you watch the hull closely, you can see it start to turn not long after the smoke starts.
I think that this is due to the side thrust, causing the ship to Dog Leg around the Dolphin protecting the bridge pier.

RE: Baltimore Bridge collapse after ship collision

lex...not a tug, and not during a hurricane. It was the MV Summit Venture and was an old bulk carrier if I remember correctly and it happened in May. Hurricane season starts in June. A squal, yes, but not a hurricane. (As long as we're asking everyone to be accurate...)

I grew up in St. Petersburg, love the "new" bridge. I had a picture of it on my office wall for a long time.

RE: Baltimore Bridge collapse after ship collision

Quote (I think the fatal error came after they regained electrical power the first time.)


Tug may be able to add something to this... but, I think that at that time, it was already too late.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

"Pretty sure piers are NOT designed for a fully loaded container ship to impact them, regardless of speed. Let's be more judicious on the whole "defective design" folks. Find a referenced standard and know what you're talking about, please."

Well, yeah. That's why they put fenders around them. The fenders around the San Francisco Bay Bridge protected the piers from the Cosco Busan, in 2007. A fully loaded container ship, as I recall. One could even think that they were NOT a defective design.


spsalso

RE: Baltimore Bridge collapse after ship collision

(OP)
Fenders are just for fending aren’t they? Not for stopping a container ship T-boning a structure.

RE: Baltimore Bridge collapse after ship collision

This ship is likely twice as heavy as the Cosco Busan. Ship sizes have increased astronomically over the last 10 years. Bridge fendering, even if present, would likely be obsolete.

Dik, it's possible a steering command was given and then the power failed. The rudder should hold its position for some time, moving slowly due to hydraulic leakage. Modern ships often use rotary vane steering gears which can be quite leaky vs the Rapson slide types.

If they did experience a steering gear failure it is possible they were attempting to use the bow thrusters to steer the ship with insufficient generating capacity on the bus. This could cause the brown out and black smoke.

https://www.wartsila.com/encyclopedia/term/steerin....

RE: Baltimore Bridge collapse after ship collision

but, would being able to correct for this have avoided the collision?

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

dik, you also have to realize that, despite the size of these ships...the crew is really small. 20-30 people. So there's not a lot of man power to go around in a time sensitive casualty. In the Navy, we had a 'special sea and anchor detail' that would be set when entering or leaving port for situations just like this. But we had a lot of extra people. So we could spare an extra operator to stand next to the manual override to manual crank the rudder over if it came to it. I had to sit at one of the emergency switchboards to shift one of the emergency diesels onto the bus if needed. But we had more than 100 times as many people on board.

So yes, there are ways of correcting for it...but the crew on that ship probably wasn't in the right place to do it fast enough.

RE: Baltimore Bridge collapse after ship collision

And manually cranking a big rudder through the 35 degrees between hardover and midships needs time measured in minutes (even doing it with a steering motor running takes around 14 seconds.

A.

RE: Baltimore Bridge collapse after ship collision

also true

RE: Baltimore Bridge collapse after ship collision

(OP)
What specifically is the smoke from? When does smoke like that happen?

RE: Baltimore Bridge collapse after ship collision

Quote:

What specifically is the smoke from? When does smoke like that happen?

Completely unverified claim but I did read that smoke like that occurs when trying to start the engine. No idea if true

----------------------------------------------------------------------

Why yes, I do in fact have no idea what I'm talking about

RE: Baltimore Bridge collapse after ship collision

" Thus the pier structure has almost zero resistance against such impact." Your assignment is to design a concrete structure resistant to a the momentum of a 100000 tonne mass moving at 8 m/s. Let us know how you get on.

Statements like the one quoted do not belong on an engineering forum.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Baltimore Bridge collapse after ship collision

What are the harbor protocols when a ship of that size loses power within a harbor area? Are they immediately required to contact the harbor authorities?

RE: Baltimore Bridge collapse after ship collision

Actually only moving at 7.5 kts = 4 m/sec.

But these vessels are just ginormous.

A bridge is always going to be at risk of being hit by a vessel. There were protection structures but the vessel turned just at the wrong moment. You can only deflect, not stop.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Baltimore Bridge collapse after ship collision

Quote (dik, you also have to realize that, despite the size of these ships...)


That's what I'm wondering. At the time of the power failure, was it already to late to avoid the collision? ... even if they were in the right spot at the right time?

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

Fenders are not supposed to stop a ship. But that is the purpose of dolphins, a significant distance from the pier. The ship varied course quickly and missed the dolphin. The dolphin may not have held either. Current methods would be to build a subsurface island around the pier to ground a ship before it hits. But this channel is quite narrow. May not be room for the island.

Now is the time to reconsider tunnelling. The bridge is a write off, and may no longer be the best solution.

RE: Baltimore Bridge collapse after ship collision

Anyone have any info on the tidal currents in that harbor at the time of the accident? They can significantly affect navigation.

RE: Baltimore Bridge collapse after ship collision

Noaa T

RE: Baltimore Bridge collapse after ship collision

The real question is who pays for it?
Insurance or the company that owns the ship? Or yeah the other option.

RE: Baltimore Bridge collapse after ship collision

NOAA tides and currents shows winds < 10mph
The display of space under the bridge indicates the tide had just turned and at the time of the last data recorded - same time as the collision. Nothing unusual about the weather.

RE: Baltimore Bridge collapse after ship collision

Quote (spalso)

The fenders around the San Francisco Bay Bridge protected the piers from the Cosco Busan, in 2007. A fully loaded container ship, as I recall. One could even think that they were NOT a defective design.

The protection for the piers is more like a concrete island: Link

Quote (tomfh)

Right, and the SF protection is much, much more than fenders.

RE: Baltimore Bridge collapse after ship collision

Quote (phamEng)

despite the size of these ships...the crew is really small. 20-30 people.

And, I was thinking, half of them were probably asleep!

RE: Baltimore Bridge collapse after ship collision

Quote (enginesrus)

The real question is who pays for it?
Insurance or the company that owns the ship? Or yeah the other option.

For some reason (election, anyone?), Biden decided to say that the TAXPAYERS were going to foot the bill for the new bridge. (He said "Federal government", but he meant "taxpayers".) I would hope that he means the cost after the owners of the Dali and their insurers pay to their limits.

RE: Baltimore Bridge collapse after ship collision

No, he means the Feds will pay, and then try to recover from insurance.

RE: Baltimore Bridge collapse after ship collision

2
For the sake of the city it seems more prudent to prioritise building the replacement bridge/tunnel immediately and chase the money from insurance. I can't imagine the local community or economy is going to enjoy not having this bridge.

----------------------------------------------------------------------

Why yes, I do in fact have no idea what I'm talking about

RE: Baltimore Bridge collapse after ship collision

3
Are you guys really going to discuss who pays? Regardless of the administration, this critical infrastructure will be rebuilt because:
1. The port function of the city and state depend on the waterway being passable.
2. The details of fault / who, what, and where are going to take years to figure out.
3. The cost of a municipality building a bridge means the society and economy grow dependent on the infrastructure. The only entity able to fund this on short notice is a government. That is what governments do.

RE: Baltimore Bridge collapse after ship collision

Admiralty Law (aka, maritime law) has a hard limit on the liability of a ship owner for an accident like this. The limit is the value of the vessel and the cargo. While this vessel and cargo were likely pretty valuable by vessel and cargo standards, it will be a very, very small percentage of the restoration cost for this crossing. It may sound crazy, but I know from painful, personal experience, that how it works.

RE: Baltimore Bridge collapse after ship collision

Why would an engine smoke like that? In the past it could be due to overloading. Current engines have smoke limits and would not smoke like that without a failure. This ship is new enough that its engines will be under emissions controls but I don't know the international rules.

This level of smoking is usually the result of a turbocharger failure. If it's a Himsen engine I believe they have a defect in the assembly procedure of their cylinder head that could cause water to enter cylinders and cause the engine to operate as if overloaded.

RE: Baltimore Bridge collapse after ship collision

Quote (dik)

That's what I'm wondering. At the time of the power failure, was it already to late to avoid the collision? ... even if they were in the right spot at the right time?

She didn't seem to really turn towards the bridge pier until power was restored after she first went dark. Unless the current was carrying her towards the pier, I don't think the allision was inevitable before she turned. My skills are for vastly smaller craft, but I think what I'm seeing is her going full astern when the power is restored, and the turn being the result of prop walk from a right-handed prop. Prop walk can really kick the stern of a vessel out if you lean hard on the power astern (for a single conventional shaft arrangement). The dense black smoke could maybe (I'm guessing here) be from reversing the main engine and pouring on the power to get the shaft spinning again to do a crash stop.

RE: Baltimore Bridge collapse after ship collision

One of the most expensive maritime losses was the MOL Comfort. It broke in half and sank in deep water in the Indian Ocean, all cargo lost. The insurance payout was $300-400 million. The hill and machinery was $66 million of that. The MOL Comfort was 8000 TEU, the ship in this incident may be double. The Dali is 10,000 TEU so it is somewhat larger. Then again, the ship was likely full of empty containers so that may reduce the value of the insurance claim.

RE: Baltimore Bridge collapse after ship collision

Thanks Murph... my skills are limited to an 18' outboard motorboat, or a canoe...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

Murph, I was referring to the generators.

RE: Baltimore Bridge collapse after ship collision

The owner of the ship involved in the Baltimore bridge disaster may be protected from a higher liability by an 1851 maritime law:

Titanic law could help ship owner limit liability in Baltimore bridge collapse

https://www.straitstimes.com/world/united-states/t...

An excerpt from the above item:

The owner of the Singapore-flagged ship that rammed into a Baltimore bridge could face hundreds of millions of dollars in damage claims after the accident sent vehicles plunging into the water and threw the eastern US transportation network into chaos.

But legal experts said there is a path for reducing liability under an obscure 19th-century law once invoked by the owner of the Titanic to limit its payout for the 1912 sinking.

At the centre of the legal fallout will be Singapore-based Grace Ocean, owner of the container ship Dali that crashed into the Francis Scott Key Bridge on March 26 at the start of a voyage chartered by the shipping giant Maersk.

The company could face a bevy of lawsuits from multiple directions, including from the bridge’s owner and anyone who sues for personal injury or emotional distress. Damages claims are likely to fall on the ship owner and not the agency that operates the bridge, since stationary objects are not typically at fault if a moving vessel hits them, said Professor Michael Sturley, a maritime law expert at the University of Texas at Austin’s School of Law.

But, according to Tulane University’s Maritime Law Centre director Martin Davies, an 1851 law could lower the exposure to tens of millions of dollars by capping the ship owner’s liability at how much the vessel is worth after the crash, plus any earnings it collected from carrying the freight on board.

The law was passed initially to prevent shipping giants from suffering steep and insurmountable losses from disasters at sea. An eight-figure sum, while still hefty, would amount to “considerably less” than the full claims total, he said.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: Baltimore Bridge collapse after ship collision

They are looking at contaminated fuel as the culprit. Whether or not dirty fuel or water contamination as Tug suggested is just a maybe.

RE: Baltimore Bridge collapse after ship collision

I read that they radioed a Mayday and traffic on the bridge was being stopped or had been stopped by the time of impact. It so, that is an impressive reaction time which saved lives.


Quote:

You can only deflect, not stop.

It appears the pier withstood the impact. The bow overhang wasn't so kind to the bridge structure on top of the pier though.

RE: Baltimore Bridge collapse after ship collision

A question might be, does the ship plow through the bridge pier or does the pier plow through the ship hull? Both? There is too much inertia to stop it without dumping the energy into breaking and / or deforming something.

RE: Baltimore Bridge collapse after ship collision

I'm not totally bought in on fuel contamination but wouldn't rule it out.

The fuel systems on ships consist of storage tanks, a settling tank, and a day tank. Daily fuel transfers are made into the settling tank. Fuel is drawn from the settlers through centrifuges and transferred to the day tank. The centrifuges should manage any water in the fuel.

There has been a high profile case of fuel contamination that caused a total loss of power on the vessel. It was a tugboat Aiviq. The day tank vent was installed in an area of the vessel that could cause it to be submerged. If there is enough water in the fuel to cause an engine to shut down the fuel injection pumps and nozzles are likely to be damaged and require replacement. In the case of Aiviq the injectors had to be airlifted to the tug to get it running again. In videos taken later in the day you can see the Dali is running its generators.

Another fuel related incident that caused a total loss of power that occurred recently was on the Moku Pahu. When making hatch cover gaskets, it's common for engineers to leave the gasket as a solid sheet instead of cutting a ring that covers only the flange. In this instance, the not compressed portion of the gasket fell onto the day tank and then became lodged in the fuel totalizer.

Finally, in environmental control areas ships are required to switch from heavy fuel oils to distillate oils. Loss of power incidents are very common during this transition. Distillate fuels has to be gradually blended in to maintain a viscosity number while the fuel system is simultaneously cooled from ~300-350°F to ambient. This is typically done more than 25 miles offshore and should not factor in to this incident.

RE: Baltimore Bridge collapse after ship collision

Quote (LittleInch)

A full steel structure going down into the caissons would have given some resistance?

None. That ship was traveling over 7 kts. It's 1000 feet long, 150 feet wide, and weighs in the neighborhood of 160,000 tons. If you want to stop it, you have to do it way before it gets to the caisson.

Quote (FacEngrPE)

A question might be, does the ship plow through the bridge pier or does the pier plow through the ship hull? Both? There is too much inertia to stop it without dumping the energy into breaking and / or deforming something.

The answer is both - see elsewhere in the thread for a picture of the bow of the boat.. there is significant damage. I assume there is likely very significant damage to the bulbous bow below the waterline as well.

RE: Baltimore Bridge collapse after ship collision

Since most tunnel operators prohibit dangerous cargo from going through them, a new tunnel will not help with traffic. A new bridge must be built to close the 695 beltway loop around the city. Not sure if a tunnel could be built that would survive a terrorist attack if the allowed dangerous cargo to go through them. Of course any terrorist who wanted to blow up a tunnel would not declare their cargo anyway, besides it would be a suicide mission.
The bridge was originally built because it was lower cost then the proposed tunnel solution.

"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli

RE: Baltimore Bridge collapse after ship collision

I think the lack of dolphins or other protection at the piers would be part of the reason USA infrastructure gets a C-.


I doubt designers in the 70's envisioned a modern container ship. Here is an image of a 1977 container ship. I am not much of a mariner, so they could have been larger than this.

RE: Baltimore Bridge collapse after ship collision

I think it is possible that some influential companies have cooperated/colluded to sink this bridge
The fact that the incident is almost impossible to happen
There are many ways that could have stopped the runaway ship, including dropping three anchors, even when the propulsion engines or power generators were not working!

RE: Baltimore Bridge collapse after ship collision

They have to eliminate the maritime insurance law for all inland shipping, for a start, and have real insurance policies.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

Quote (ALK2415)

There are many ways that could have stopped the runaway ship, including dropping three anchors, even when the propulsion engines or power generators were not working!

I think you are vastly overestimating the ability of an anchor (or even 3 of them, if there were enough deckhands available to get them all out in time) to stop 100,000+ tonnes moving at around 4 m/s (8 knots) in maybe 1000 m (I'm guessing the distance available once they knew disaster was likely). Even if the 56,000 hp main engine was working at full power output (and I personally think it might well have been), that wouldn't have been sufficient to pull off a crash stop in that sort of distance.

Have you ever tried to stop a vessel doing 8 knots? The speed seems low compared to other modes of transport, but stopping is difficult (not counting very lightweight craft, i.e. something with a good bit of mass for its size).

The incident is very possible through just ordinary bad luck or poor maintenance. Ships have control, power, and propulsion problems. It's a relatively narrow channel between those bridge piers for that size of ship. People make mistakes (e.g. going full astern, if they did, might turn out to be a critical mistake here, where full ahead might have allowed them to steer away from the pier).

RE: Baltimore Bridge collapse after ship collision

2
Nothing would have prevented this accident except better, much better, protection for the piers. If the ship grounded on an underwater island before the pier, the channel might be closed for a few days, but nothing like this disaster.

RE: Baltimore Bridge collapse after ship collision

Another recent, though less catastrophic crash, was a ship that had enough overhang at the bow to clean the cargo cranes right off the solidly built dock as it came in at about 30 degrees to the dock.

RE: Baltimore Bridge collapse after ship collision

Reports suggest the anchors were dropped shortly after the incident occurred. We have an M1V1 problem here. So far this seems a genuine accident.

RE: Baltimore Bridge collapse after ship collision

Many similarly configured harbors require ships to have tugs move the ship the entire way past the bridges.

RE: Baltimore Bridge collapse after ship collision

When you leave tugs attached to big ships that are steaming fast enough for their steering to be effective, there's a significant risk of girting and sinking the tugs. It might be better economically, but not in terms of Risk to Life.

RE: Baltimore Bridge collapse after ship collision

They don't attach to ships that are steaming fast at all. It's an accepted and widely used practice. It's costly and not economic except it is for safety.

RE: Baltimore Bridge collapse after ship collision

Quote (ALK2415)

I think it is possible that some influential companies have cooperated/colluded to sink this bridge
The fact that the incident is almost impossible to happen
There are many ways that could have stopped the runaway ship, including dropping three anchors, even when the propulsion engines or power generators were not working!

ALK. Thanks for continuing to amazing me on how many engineers have no clue about momentum and fail to grasp just how big these ships are. 20 anchors wouldn't have stopped this ship in time! Also anchors don't work the way they do in movies. A small piece of metal dragging across sand isn't going to do much.

RE: Baltimore Bridge collapse after ship collision

Yeah, but not just momentum and what can be achieved with an anchor. Until you've tried to stop a 45-50+ foot vessel doing 8 knots, it's difficult to understand the difficulty of doing a crash stop on water. It's got to be at least 45-50 foot waterline length due to the "hull speed" physics, where shorter hulls will have massive additional drag slowing them down by the time they get to 8 knots. You then need to adjust your mental picture from a small craft having probably something like 1-10 hp per tonne, and the ship in this incident having around 0.5 hp per tonne from the main engine (and reversing involves stopping the engine and then restarting the entire engine in reverse, as the crankshaft is essentially directly coupled to the fixed blade propeller).

RE: Baltimore Bridge collapse after ship collision

For a large ship like this that doesn't have azipods and bow thrusters, to be allowed to traverse through inland channels with bridges etc. and not under control of tugboats. Someone some where is and was not using much logic. Even most of the highly maneuverable cruise ships have tug boat escorts though I'm not sure what countries do that. I've seen it on cruise ship tv shows.

The excessive smoke from the engines looks like they were throttled up, then backed off. What engine or engines does this ship have? How many props?

RE: Baltimore Bridge collapse after ship collision

Quote (enginesrus)

The excessive smoke from the engines looks like they were throttled up, then backed off. What engine or engines does this ship have? How many props?

https://ships.jobmarineman.com/dali-9697428/
It's a single MAN B&W 9S90ME-C9 (56396 hp, 2 stroke diesel, 9 cylinder, 3260mm stroke, 900mm bore) with a fixed pitch propeller. 4 or 5 stories in height.

RE: Baltimore Bridge collapse after ship collision

One thing to note is that a ship's propeller only generates about 50% of its rated load when operating astern. It should not load the engine to cause it to smoke like that.

RE: Baltimore Bridge collapse after ship collision

This article in the Daily Mail and a similar one in Daily beast caught my eye, but I'm not sure how reliable these reports might be.

Dali cargo ship suffered 'severe electrical problem' while docked in Baltimore days prior to bridge collapse crash that saw it suffer 'total power failure, loss of engine failure', port worker says

https://www.dailymail.co.uk/news/article-13246079/...

https://www.thedailybeast.com/port-worker-says-dal...

RE: Baltimore Bridge collapse after ship collision

(OP)
How do the dolphins work? Where does all that energy go?

RE: Baltimore Bridge collapse after ship collision

The insurance claims might be big money, but like we saw in the Suez grounding, shipping have their own rules dating back centuries to limit the claim on the owners to the vessel and cargo value.

The insurers will very soon declare "general average" I think to share the costs.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Baltimore Bridge collapse after ship collision

Quote (Tomfh)

How do the dolphins work? Where does all that energy go?

Some will be lost to ablation of the dolphin. Some will be used deflecting the ship to the side (it's unlikely to be a perfectly aligned hit, so it's going to be to one side of the ship's centerline). The rest goes to tearing away shell plating and turning heavy steel into mangled scrap.

That's assuming the dolphin is securely attached to the planet. Build quality may vary.

RE: Baltimore Bridge collapse after ship collision

As someone notes... a ship of that mass travelling at that speed, will require a really big dolphin... pipe

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

I have seen dolphins bend and rebound when impacted by a large ferry.
I used to ride a ferry every week.
As memory serves the capacity would have been about 80 cars and 600 passengers.
At one side of the approach to the dock were a line of dolphins, at the other side one or two dolphins.
At times a "Cowboy Captain" would come into the wharf too fast and scrub off speed by hitting a dolphin a glancing blow.
The dolphin would deflect and rebound.
The rebound would push the ferry across to the other side were it would sideswipe one or two more dolphins.
That, combined with bow thrusters and/or reverse thrust would slow the ferry almost to a stop.
Most of the energy and speed lost would be scrubbed off by the redirection of the mass of the vessel to an altered line of travel.
These dolphins were not solid concrete but the old school, driven pile dolphins.
That is, a large number of driven pilings were bound together by cables.
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Baltimore Bridge collapse after ship collision

I strongly disagree with this. A glancing blow is one thing but if energy is being dissipated metal is getting bent. We use tires and rubber fenders to absorb energy on the tugs but any time the tugs make contact where the tires don't protect there is usually significant structural damage.

RE: Baltimore Bridge collapse after ship collision

I was there, you weren't.
How much energy is needed to change the vector of travel of a ship?

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Baltimore Bridge collapse after ship collision

Any force > 0. The question is how quickly you want to change the vector of travel.

In your case the ferry may have touched the whalers but the engine was doing the braking.

Here is a recent example of the results of a ferry using whalers as brakes.

RE: Baltimore Bridge collapse after ship collision

I was there Tug.
I saw the dolphins bend/deflect several feet as the ferry hit a glancing blow.
The dolphin then rebounded and the ferry hit the dolphin on the other side a glancing blow.
A small part of the energy may have been dissipated by the shock absorbers of 80 cars rocking from side to side.
Not a lot of energy, but a strong indication that the vessel had been redirected.
A normal landing would rely on the bow thruster and reverse thrust.
When the ferry was obviously coming in faster than usual, we would do the dolphin bounce.
A lot of the old dolphins have been replaced by these rebound structures.

These are not intended to take a direct hit but work very well when struck a glancing blow by a ferry.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Baltimore Bridge collapse after ship collision

That damage was not done at that spot.
That vessel hit something lower at another time.
Our ferries had substantial rub rails.
The dolphins had lots of rub marks.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Baltimore Bridge collapse after ship collision

TugboatEng, what's your pro take on the prop walk theory a couple of folks have proffered above? It rings true to me but I'm way out of my element.

Not-very-enlightening side comments:

1) If I dropped anchor on my old 32 ft sailboat while at an 8 knot clip that would have severely messed my boat up. I seriously doubt anchors would do much here unless they were deployed well in advance, also

2) I fully understand the "administration buying votes with a bridge bailout" sentiment, but the complete closure of the Port of Baltimore is, among other things, probably a national security risk at a minimum.

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com

RE: Baltimore Bridge collapse after ship collision

Prop walk is certainly a factor in ship handling. When backing down prop walk would push the stern of the ship to port. As the ship slows the effect will become more pronounced.

RE: Baltimore Bridge collapse after ship collision

@ human909 : its not my own theory of ship control this was from experts interviewing form UK across BBC and sky news ...
.
After all types of technological advances in ship controlling and shipbuilding industry, its not reasonable leaving it for single human being "the harbor captain" to make such a mistake in directing the ship, or at least change its course, when the engines stop.

As they always say, when there is no possibility of failure, there is always something stinky about the event.

Tracking leads start from the ship owner and operator, as well as the port administration
Instead of focusing on tedious engineering analyses, let the concerning parts do their work to find the faulty persons involved ..
Whoever did this act had the ability and full knowledge of the Impact force and the momentum available in this ship and made all these calculations to cause this damage. At least this is my personal opinion!

RE: Baltimore Bridge collapse after ship collision

11
Tedious engineering analyses? THIS IS AN ENGINEERING FORUM. IT'S WHAT WE DO.

No possibility of failure? Have you ever been on a ship? Everything fails. All the time. The marine environment is BRUTAL.

If you really think somebody could have monitored tides, currents, and winds along with aligning schedules just so and then be such an amazing ship handler as to line it up perfectly 5 minutes out and then cut power to the entire ship at just the right moment to make it turn and hit at the perfect angle...you're off your rocker.

Please, leave the conspiracy theories for whatever dark, dank hole in the internet they came from and let us discuss actual engineering principals and lessons to be learned.

RE: Baltimore Bridge collapse after ship collision

These ships have multiple nationality crews which I think would prevent the coordination required to intentionally pull off a collision like this. I believe the officers on the ship were Ukrainian and the crew was Indian.

RE: Baltimore Bridge collapse after ship collision



From the recent NYSB footage it appears the demolished pier's marine works, that is the pile caps and the vertical and raking piles underneath the water (or the cassion structure if used), remains intact. The fender system seems complete and there is no visible movement in the pile caps. Only the twin A-frame columns were removed on impact. All four reinforced concrete columns were broken off cleanly. Three of pile caps are now visible with separation face at about 45 degree. Only one column is visible now lodged with the bow of the cargo ship. It is trapped by the falling deck. It is also possible that the deck may be covering some of the remaining three columns which appear to be hollow in section [see post by ZR Shipwright (Marine/Ocean) at 26 Mar 24 15:12] or the photo re-posted below. The RC design code ACI-318 has in recent years has tightened the requirement of stirrups or lateral links, like every alternate vertical bar in compression bar has to be confined by a link, which are glaringly missing in the failed column.
.

The enhanced video provided by NTSB also shows two locations where materials and dust were blowing away like explosion during impact. This could occur if the RC columns were heavily loaded in compression and failed by buckling.

RE: Baltimore Bridge collapse after ship collision

Regarding fenders - I've never designed them for a bridge, but I've done several for mooring facilities.

Timber dolphins or timber fender systems use energy dissipation in the wood. You essentially derive a spring constant from the piles and then determine the amount of energy it can store. Haven't done one in a while and my marine facility design references are in a box at the moment.

On larger facilities for ships, we usually use rubber fenders. The manufacturers publish energy absorption graphs for various temperatures and impact velocities. I would include in my design documentation a maximum pressure on the fender plate along with a maximum considered velocity. The facility owner would then include that information in communication with the ship's master and they'd work out the details. One job had a permanent barge moored against the fenders to 'even out' a oddly shaped wharf (facility originally built in the late 1800s, updated in the 1940s, and then they found ships in the 80s didn't fit anymore). The barge was ancient so we had to consult with a naval architect to get allowable hull contact pressures to make sure its hull didn't become part of the energy absorption equation for normal mooring operations.

RE: Baltimore Bridge collapse after ship collision

StreamTime Live - Youtube Port of Baltimore

Web cam location appears to be at Riviera Beach.

RE: Baltimore Bridge collapse after ship collision

I suspect a ferry is just a fraction of the mass.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

John, you don't want to go there.

Skip,

glassesJust traded in my OLD subtlety...
for a NUance!tongue

RE: Baltimore Bridge collapse after ship collision

Quote (waross)

The dolphin then rebounded and the ferry hit the dolphin on the other side a glancing blow.

A big bounce suggests a lack of energy absorption.

As to anchors: I started a thread here on Tuesday about a cruise ship that suffered a TLF and came perilously close to catastrophe. In that case, they were doing 4 kt and had time to let a couple of anchors go. All that did was to rip the flukes off one (probably both actually, but they never got the other one back) of the anchors and complicate the task of extricating the ship from a nasty corner once propulsion was restored.

A.

RE: Baltimore Bridge collapse after ship collision

Quote (enginesrus)

For a large ship like this that doesn't have azipods and bow thrusters, to be allowed to traverse through inland channels with bridges etc. and not under control of tugboats. Someone some where is and was not using much logic.

She has a 4,000hp bow thruster.

https://en.wikipedia.org/wiki/MV_Dali

RE: Baltimore Bridge collapse after ship collision

There is a reason it is going around the internet. Someone is spreading it.

RE: Baltimore Bridge collapse after ship collision

First a very short comment regarding the cost. I saw the statement President Biden made that the federal government will pay. As I understood it, the reconstruction needs to start fast because Baltimore can't wait for the legal issues to finish. Therefore, the federal government will pay initially.

Regarding the crash, something that is probably more interesting in this forum. I was actually involved in designing a crash barrier for a ship a few years ago. The size of that ship was significantly smaller.

What we are dealing with here is kinetic energy, and lots of it, just to test some approximate numbers. Say 160 000 tons at 7 kts (3.6m/s). If that is the weight of the ship the moving mass will actually be larger because the water close to the hull will move with the hull. But I skip that for now.

Wk= 160 000 tonne * (3.6 m/s)^2 * 0.5 = 1.0 G Joule = 1.0 GN m

To stop this, we need something very strong and very ductile. Let's assume that we can go directly to plastic deformation. Something that can withstand 500 Mega Newtons for 2 meters would work. Part of the energy will of course be absorbed by the ship itself. Even if I assume that the ship and the barrier will "share" the energy 50/50 the numbers are bad.

Either a longer stopping distance is required or, probably better, don't stop the ship, "only" change its direction.

But I have a question regarding this. I am well aware of that this bridge is not new. But if it was new, would it be acceptable that the fairly limited damage we see leads to a total collapse?

RE: Baltimore Bridge collapse after ship collision

Quote (ThomasH)

But if it was new, would it be acceptable that the fairly limited damage we see leads to a total collapse?

To me, it appears the answer is no. With insurance claim estimates in the $2-4B range and the cost of a new bridge being around $600M, you have all the reason to build a protection system to stop or deflect a ship from demolishing the bridge.

RE: Baltimore Bridge collapse after ship collision

ThomasH - I'd expect any new structure would have better protection. A bigger island and/or more dolphins around the bridge piers for sure. But, yes if a bridge support managed to sustain that much damage then I'd fully expect the bridge to collapse.

RE: Baltimore Bridge collapse after ship collision

If you can't accommodate a direct impact with whatever is floating/steaming down the river, then you apply failsafes in whatever form necessary. Could be barriers, redundant structure, etc.

RE: Baltimore Bridge collapse after ship collision

Hats off to the bridge shutting down so fast.

RE: Baltimore Bridge collapse after ship collision

The cost of the bridge is one thing, the value is quite another, and exceeds the cost by a wide margin.

RE: Baltimore Bridge collapse after ship collision

had this discussion a month ago about diversion choices to a single runway hub.

Shut everything down for 12 hours or go and screw Ryan Air up for 12 hours...

RE: Baltimore Bridge collapse after ship collision

Quote (LionelHutz)

ThomasH - I'd expect any new structure would have better protection. A bigger island and/or more dolphins around the bridge piers for sure. But, yes if a bridge support managed to sustain that much damage then I'd fully expect the bridge to collapse.

I agree with you. I don't know in detail how US codes have evolved over time but I know that other codes have changed regarding things like redundancy.

On the other hand, to be able to withstand the impact from a ship of this size may not be reasonable. There is also the probability for an accident to actually happen. It may seem a bit cynical, but risk analysis has to weigh the cost vs the benefit.

The best thing now I think is to try to learn from this and try to prevent it from happening again. But anybody who thinks this ship would have been easy to stop, I don't share that idea.

Quote (Alistair_Heaton)

Hats off to the bridge shutting down so fast.

Couldn't agree more.

RE: Baltimore Bridge collapse after ship collision

2
The new bridge needs to be built with a longer main span, so that the supports are well clear of the channel. The span is/was 1200 feet. By comparison, the much older (1952) Chesapeake Bay Bridge downstream at Annapolis has a main span of 1600 feet.

RE: Baltimore Bridge collapse after ship collision

Yes, Hokie, that would seem to be a reasonable criteria for whatever type of replacement structure is finally approved to replace the Francis Scott Key bridge, which I assume will carry the same name (after all, he was associated with Baltimore, but then so was Edger Allan Poe).

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: Baltimore Bridge collapse after ship collision

The bridge and pier, as un-intended as it was for that purpose, stopped the ship. It follows that there is really no reason and no excuse for this tragedy considering our understanding of infrastructure protection. This is an event that simply cannot be allowed to happen.

A simple risk matrix would have put this bridge at the top of the list for additional protection against accident or sabotage.

RE: Baltimore Bridge collapse after ship collision

Wait until that risk matrix includes large commercial passenger jets.

RE: Baltimore Bridge collapse after ship collision

ALK2415 (Structural)28 Mar 24 14:47

Quote (ALK2415)

@ human909 : its not my own theory of ship control this was from experts interviewing form UK across BBC and sky news ...
.....
Whoever did this act had the ability and full knowledge of the Impact force and the momentum available in this ship and made all these calculations to cause this damage. At least this is my personal opinion!
I question the 'experts'. So should you. We also have experts on this forum.

Quote (charliealphabravo)

It follows that there is really no reason and no excuse for this tragedy considering our understanding of infrastructure protection. This is an event that simply cannot be allowed to happen.

A simple risk matrix would have put this bridge at the top of the list for additional protection against accident or sabotage.
If we are talking about sabotage 99.99% of our infrastructure is not protected against sabotage. And plenty is remote and has no protection, any motivated party can cause damage with explosives, oxy or even saws. Regarding accidents... Well pretty much every movement of vessels of this size can have serious consequences if things go awry.

Your black and white view on thing lack suitable nuance and understanding of the bigger picture.

RE: Baltimore Bridge collapse after ship collision

Quote (Wait until that risk matrix includes large commercial passenger jets.)


...maybe a lot less likely than an errant cargo ship?

Maritime insurance has to change. The ship owner has to be liable, rather than the public. If no insurance, then no entrance to the inland waters. The insurance has to be one that the insurance company 'cannot wiggle out of'. It has to be total coverage of events, and for full value (no freak of nature, or 'Act of God' exclusions.

Any barriers have to be well placed to notify the cargo container ship well in advance of the bridge. Maybe specialised 'lanes' or the use of a pilot that knows the watercourse (didn't work so well in Suez, but I've never had any confidence in their skills). pipe

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

Ships are built to the rules of classification societies. Nothing more and nothing less. Regulatory bodies such as US Coast Guard lean heavily on class societies to make rules as they don't have sufficient knowledge. Class societies are hired and there are many so there is competition to make low cost ships. Ships have extremely limited redundancy.

RE: Baltimore Bridge collapse after ship collision

Quote (human909)

Your black and white view on thing lack suitable nuance and understanding of the bigger picture.

A risk matrix provides the opposite of a "black and white" assessment. Unfortunately, this structure was not protected against the most critical and obvious eventuality, one with the most devastating consequences, and the one with the simplest and cheapest protection method. A failure on all three axes.

RE: Baltimore Bridge collapse after ship collision

Concur... but there are some things and loadings that cannot be protected against and that other options must be considered. pipe

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

The FAA KNEW 100% that anyone except flight crew in the cockpit was a bad deal and waited for 4 aircraft to be hijacked before requiring locks on doors and keeping hijackers away from the pilots.

This tragic cost was a half dozen or so lives and a large amount of inconvenience and tax money to replace the bridge.

The 4 planes cost 3000 lives, more than 3000 service member lives, 100s of thousands of civilian lives, millions of people displaced and likely eight trillion US dollars.

The FAA simply chose to do nothing about it.

But for structures, it's the difficulty of preparing for those who plan to do damage that's a problem without good solution.

The tragedy here is this bridge has been in place since the Sunshine Skyway Bridge disaster 42 years ago, plenty of time to have put into place the same protections the Sunshine Skyway Bridge now has.

RE: Baltimore Bridge collapse after ship collision

Quote (dik)

Maritime insurance has to change. The ship owner has to be liable, rather than the public. If no insurance, then no entrance to the inland waters. The insurance has to be one that the insurance company 'cannot wiggle out of'. It has to be total coverage of events, and for full value (no freak of nature, or 'Act of God' exclusions.

Raising or removing the cap on marine liability will be paid for by the general public. Ship owners / operators will be hit by significant increases on insurance, and just pass that on to the shippers, who will ultimately pass that on to the public at the cash register. Insurers will make a bit more money out of it, as they will err on the side of profit, rather than just covering the expected liability.

RE: Baltimore Bridge collapse after ship collision

Quote (charliealphabravo)

The bridge and pier, as un-intended as it was for that purpose, stopped the ship.

I just want to add some nuance to this smile. The ship hit the pier and a relatively small part of the bridge. From what I have seen I would say that the bridge failed because it lost its support. It seems to have dropped mostly downwards.

Most of the impact energy was handled beneath the water surface. Perhaps the pier was part of a much larger structure. I am just speculating since I have no more information than the videos.

RE: Baltimore Bridge collapse after ship collision

dailymail.co.uk - Dali cargo ship suffered 'severe electrical problem' while docked ...

Quote (dailymail.co.uk)

... the ship was anchored at the port for at least 48 hours prior to the deadly crash.

'And those two days, they were having serious power outages… they had a severe electrical problem. It was total power failure, loss of engine power, everything.'

I don't know anything about how ship resources are distributed but this seems more like electrical issues impacting mechanical side rather than a drive train issue.

RE: Baltimore Bridge collapse after ship collision

Quote (Raising or removing the cap on marine liability will be paid for by the general public.)


Yup... but less directly than the current method and by those that are using whatever the cargo is. In addition, if some items become more expensive it cause others to reconsider if they really need that object.

It's not passed on to the public, in general, but mostly to those that would want the commodity. This is a little more fair. pipe

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

Quote (ALK2415)

@ phamENG this is the third time you had this big mouth!!!
THAT'S HILARIOUS!!!!

Brad Waybright

The more you know, the more you know you don't know.

RE: Baltimore Bridge collapse after ship collision

Quote (ALK2415)


@ phamENG this is the third time you had this big mouth!!!
just keep it to your-self. and yes there is something FISHY about this incident

Not sure what you're referring to here. Please explain.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: Baltimore Bridge collapse after ship collision

Anyone hear the joke about the 3 conspiracy theorists that walked into a bar?

RE: Baltimore Bridge collapse after ship collision

It could not have been a coincidence!

RE: Baltimore Bridge collapse after ship collision

As has been pointed out repeatedly in mass media, container ships have been getting larger and larger and HUGE-ER!

And that has been happening over the past 50 years, or so.

So, although it's a surprise to mass media, it wouldn't be a surprise to anyone dealing with ocean shipping. Like people who are in charge of a bridge, which such ships pass under. And people in charge of the safe operation of that bridge.

With 50 years of warning, nobody thought that this bridge needed a little attention?

More to the point, who would that "nobody" be? Or is it really nobody?

Since the Coast Guard should be guarding our coast, and these bridges ARE on our coast, and since there IS a matter of national security here, I think maybe the Coast Guard should be expanded just a little, to encompass inspection and modification of these bridges. Their military authority might come in handy. Oh, yes: The Corps of Engineers should be their technical advisors.

Or, of course, we could do nothing. Such a bad-luck circumstance is indeed extremely unlikely to repeat itself, so maybe doing anything is uncalled for.


Just a thought,


spsalso


RE: Baltimore Bridge collapse after ship collision

In reality, the Army Corp of Engineers is generally responsible for maintaining the nation's various navigable waterways, be it a river, channel or harbor (my Army Reserve time was in the Corps of Engineers).

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: Baltimore Bridge collapse after ship collision

Quote (@ phamENG this is the third time you had this big mouth!!!)


Gentlemen...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

RE: Baltimore Bridge collapse after ship collision

Spalso, the jumbo-ification of container ships is actually a very recent trend starting. There was a sudden jump in size between 2006 and 2011 with the Maersk Triple E setting the standard. There was a massive building campaign for ships this size and they started becoming common around 2015. There has not been 50 years for infrastructure to catch up.

At least the Triple E was a twin screw ship which would have prevented this incident altogether.

RE: Baltimore Bridge collapse after ship collision

If you care to look at the map of the lower Chesapeake bay, there are NO "Tall Bridges" crossing either the mouth of the Chesapeake Bay or Hampton Roads.

Quote (https://en.wikipedia.org/wiki/Chesapeake_Bay_Bridg...)

High-level bridges were initially considered for traversing these channels. The United States Navy objected to bridging the Thimble Shoals Channel because a bridge collapse (possibly by sabotage) could cut Naval Station Norfolk off from the Atlantic Ocean. Maryland officials expressed similar concerns about the Chesapeake Channel and the Port of Baltimore.
Bridge strikes happen, to some degree it is inevitable,
So the possibility needs to be part of the design constraints.
Options include designs that limit damage to something that can be repaired in a reasonable amount of time (the CCBT above water sections) or making the sections that could have much longer repair times (the tunnels) such that a failure can not cascade to closing a ship channel.

Quote (https://en.wikipedia.org/wiki/Chesapeake_Bay_Bridg...)

The CBBT has been closed three times for multiple days after being struck by watercraft:
  • In December 1967, coal barge Mohawk broke anchor and struck the bridge, closing it for two weeks for repairs.
  • On January 21, 1970, the USS Yancey (AKA-93), a United States Navy attack cargo ship carrying 250 people, was at anchor near the bridge–tunnel. During a gale with winds gusting in excess of 50 miles per hour (80 km/h), the Yancey dragged its anchors and hit the bridge stern first, knocking out a 375-foot (114 m) segment of trestle. There were no vehicles on the bridge at the time of the impact, and no one was injured. During the 42 days it took to replace the damaged span, the Navy offered a free shuttle service for commuters using helicopters and LCUs.
  • In 1972, the bridge was again impacted by a barge that had broken loose, closing it for two weeks while the span was repaired.
  • Other, less significant strikes have caused shorter closures while the affected structures are inspected—most recently, a four hour closure after a barge strike in June 2011.
And yes hazmat needs to go via surface bridges.

RE: Baltimore Bridge collapse after ship collision

Sure, no chance to do anything. Look at the protection around the electrical towers. It was the overhang from the ship that caught and pushed down the bridge support. Had the fenders been farther away that contact would not have happened.

RE: Baltimore Bridge collapse after ship collision

Quote (FacEngrPE)

the CCBT above water sections

I crossed the CBBT the morning of the incident, after watching the videos of the bridge fall over breakfast. When a container ship rolled into view through the fog...well let's just say I didn't have a warm and fuzzy feeling...

RE: Baltimore Bridge collapse after ship collision

FacEngrPE,

Maybe not the lower Chesapeake, but the Chesapeake Bay Bridge at Annapolis is a 'tall bridge' downstream from Baltimore. Built in 1952. Second span built in 1973.

https://en.wikipedia.org/wiki/Chesapeake_Bay_Bridg...

Those bridge strikes at the CBBT had little effect on shipping, as the main channels are over tunnels.

RE: Baltimore Bridge collapse after ship collision

2

Quote (3DDave)

The FAA KNEW 100% that anyone except flight crew in the cockpit was a bad deal and waited for 4 aircraft to be hijacked before requiring locks on doors and keeping hijackers away from the pilots.

Ah, but how many pilot suicides have we had since then? And the Greek hypoxia flight. Would those have happened if others had been able to access the cockpit?

Just saying, one has to be careful that in solving one problem, one does not create another.

And I'd say the biggest deterrent to a hijacking is a plane load of passengers who know that the rules have changed, and being hijacked may not mean a quick trip to some third world country.

RE: Baltimore Bridge collapse after ship collision

How many big container ports are inland of bridges in the US?

Was this just a very rare freak crash?

It will probably now be being looked at by every big bridge authority, but could just be the worst set of circumstances here - relatively narrow bridge gap, container depot other side of it, ship lost power just at the wrong time.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Baltimore Bridge collapse after ship collision

Quote (LittleInch)

How many big container ports are inland of bridges in the US?

Not sure about containers specifically, but New Orleans (and essentially every port up river on the Mississippi) has terminals inland of bridges, part of the port of Jacksonville is up the St. Johns from a bridge, Charleston has oil and gas terminals and container terminals up the Cooper past a couple of large bridges, no containers but there is some decent shipping up the James River toward Richmond, VA that has to pass under the James River Bridge (not sure where or what, but I've had to wait on bulk carriers traversing the channel or work around them at anchor waiting for the bridge to lift), the Navy has a weapons station past a bridge up the York River, but that's mainly destroyers and cutters heading up there (everything else is small commercial watermen or pleasure boats), shipping on the Delaware River to Philly has to pass under a couple large bridges.

The list keeps going. But I'll stop. There are lots. And it's not just the big container ports that need to worry. Every facility needs to consider the vessels moving in and out of the harbor and determine what risk mitigation measures are appropriate.

I'd say yes, this was a freak accident...not because it's a bridge strike, but because of the scale. Bridge strikes are fairly common, but they're usually pleasure boaters. Professional mariners are pretty good at not hitting fixed objects. But when power goes out at the absolute worst moment...doesn't matter how good you are.

RE: Baltimore Bridge collapse after ship collision

Do you suppose they'll scrap the Dali after this mishap? There's a chunk of the bow missing above the waterline, likely damage below the waterline, exposure to the horrendous stress of the collision, and a huge black cloud of bad luck hanging over the ship.

RE: Baltimore Bridge collapse after ship collision

Not likely. Even if the damage to the bow is extensive a new bow can be fabricated and welded on.

RE: Baltimore Bridge collapse after ship collision

I'm not saying the damage will be directly comparable, but it was a similar-ish size of ship that grounded hard on a reef at 12 knots and did significant hull damage. The Exxon Valdez was repaired, renamed the Exxon Mediterranean, and had a fairly long life until she was written off in a collision with another ship many years later.

As a fairly young Neopanamax ship, I'm reasonably certain they will repair Dali.

RE: Baltimore Bridge collapse after ship collision

USS Wisconsin had a big chunk taken out of her bow when she collided with another ship in the fog just off the Virginia coast. There happened to be another ship of the same class under construction at the time, so she was ready for sea again and steamed for Spain 16 days after the incident.

RE: Baltimore Bridge collapse after ship collision

It'll depend on the economics. The amount of new container ship capacity in build at the moment seems to be outstripping the combined effects of older ships being scrapped and the growth in cargo volume - though not the (hopefully) short term increase in requirement to accommodate all the trade that's being routed round the Cape of Good Hope.

RE: Baltimore Bridge collapse after ship collision

"And I'd say the biggest deterrent to a hijacking is a plane load of passengers who know that the rules have changed, and being hijacked may not mean a quick trip to some third world country."

OK - Thanks! That makes total sense as a response. To an unasked question. The original question was, what should the FAA have done to stop a 9/11 style event, not, what is the best response AFTER the 9/11 event.

So the FAA should not require locked the doors now because, while it would have worked to stop 9/11 then, the passengers are considered the only line of defense now. Got it. Great answer. Demand the cockpit door remain open the next flight you are on because you think the pilots may commit suicide or pressurization will be lost and the crew won't respond correctly.

RE: Baltimore Bridge collapse after ship collision

I feel bad saying this, but the bridge failed perfectly.

RE: Baltimore Bridge collapse after ship collision

Quote (LittleInch)

How many big container ports are inland of bridges in the US?

It only took me about 20 minutes to scan the US coast on Google Maps looking at shipping yards and bridges. Neglecting channel depth I didn't see more than maybe one other bridge that would rank higher than the Baltimore bridge as a priority for protection. When you consider the width of the shipping lane, the number of lanes if one were to be obstructed, the type of the bridge and susceptibility of the piers to damage, the size/types/importance of upstream facilities.

RE: Baltimore Bridge collapse after ship collision

Quote:

How many big container ports are inland of bridges in the US?

The parts of San Francisco Bay require getting past at least Golden Gate Bridge, and the Bay Bridge

A part of LA Harbor requires passing a bridge

The naval base at San Diego requires passing bridge, but USN ships would never hit stuff, right?

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Baltimore Bridge collapse after ship collision

Quote (3DDave)

The FAA KNEW 100%...

No, the trillions of dollars and countless lives lost was not due to the FAA. It was due to a cultivated, cultural insecurity and who knows what kind of foreign policy rationales behind closed doors. September 11th could not have happened on September 12th, because the ruse was known. Thus, but for complacency, September 11th would never have happened.

Ultimate Safety is a never-winnable ideal. It only creates bubble boys incapable of living a relatively stress-free life.

RE: Baltimore Bridge collapse after ship collision

I don't really see most bridges being able to survive such collisions undamaged; the Bay Bridge doesn't have much protection against a ship that masses 10x+ the mass of the supports. The only protection is really how much redundancy is built into the bridge itself.


TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Baltimore Bridge collapse after ship collision



They need to add an island of rocks around these pylons like we did here in FL in Tampa Bay on the Sunshine Skyline Bridge, that is wide enough and large enough to allow a cargo ship to beach, with enough distance so the overhang of the ship sides or bow cannot reach it.

RE: Baltimore Bridge collapse after ship collision

The reasons for the attack don't matter when the way to avoid what was known to be a problem from previous hijackings and non-flight crew in the cockpit was clear.

Nice bit of strawmanning, but utterly irrelevant to doing a risk analysis.

RE: Baltimore Bridge collapse after ship collision

Quote (IRstuff)

I don't really see most bridges being able to survive such collisions undamaged; the Bay Bridge doesn't have much protection against a ship that masses 10x+ the mass of the supports. The only protection is really how much redundancy is built into the bridge itself.

Curiously, the extremely similar Forth Road Bridge was upgraded in 1999 with a series of linked cofferdam cells filled with rock and capped with concrete. There's considerably less ship traffic on the Forth than in the SF Bay. Most of the traffic is much smaller, with the exception of the occasional aircraft carrier. The steelwork of the towers was considered non-redundant and vulnerable to impact from a ship in a 1995 report; I don't see any additional redundancy in the main towers of the Bay Bridge.

RE: Baltimore Bridge collapse after ship collision

How will they cut the bridge elements? Given the loads on the structural elements this would appear to be very hazardous particularly near the bow of the boat. It's hard to imagine this would be done using torches due to the possible reactions of the structural elements on being cut. Would this be done using using a thermal material like a linear thermite charge to do the cutting?

RE: Baltimore Bridge collapse after ship collision

Quote (The only protection is really how much redundancy is built into the bridge itself.)


or, how much care is taken to prevent the accident in the first place. pipe

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

I love the Firth of Forth bridge in the background. I believe its predecessor was the subject of "Engineers of Dreams".

The caps on the Forth Road suspension bridge do not appear to provide enough distance for the overhang of a ship.

The engineering question is what is the expected cost vs the expected benefit.

RE: Baltimore Bridge collapse after ship collision

phamENG: Can I quote you in an article?

Quote (phameng)

If you really think somebody could have monitored tides, currents, and winds along with aligning schedules just so and then be such an amazing ship handler as to line it up perfectly 5 minutes out and then cut power to the entire ship at just the right moment to make it turn and hit at the perfect angle...you're off your rocker.

Roopinder Tara
Director of Content
ENGINEERING.com

RE: Baltimore Bridge collapse after ship collision

They can saw it with a chain. See *Golden Ray" for an example.



Explosives is option 2.

RE: Baltimore Bridge collapse after ship collision

They have construction vehicles that have giant metal snips on the end, they can very easily check through that, and they will cut off sections of the truss with this, and lower them with a crane down to a barge for easy floating away.

RE: Baltimore Bridge collapse after ship collision

The next step in clearing the channel is clearing the bridge structure from the bow of the ship. The plan is to cut the structure into sections, reducing weight to allow the floating cranes to begin. Too dangerous for workers to do the cutting, as the structure is likely stressed as it straddles the bow and would move when cut. Proper path is to set ignition charges (C4?) at strategic parts of the frame, with remote detontion.

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

Jeff Ostroff (Electrical): Before giant snips could be used, a stable floating platform would be needed. Like the crane barges, the platform would need to be stabilized using at least six, tensioned anchors to the waterway bottom. But the structural clutter prevents that from happening now, delaying use of the cranes.

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

We are not yet at a point where we are just chopping up scrap for the recyclers. Cutting steel trusses with any method must be done very carefully and with consideration for where those pieces that are under tremendous tension may land. The survey crews were already there on the first day to map out the exact location of the 24" gas main that parallels the bridge. They will not be using explosives or giant metal snips without doing a bit of homework on the potential for making the situation worse or endangering the people that are doing the work.

https://gcaptain.com/dali-salvage-baltimore-gas-pi...


RE: Baltimore Bridge collapse after ship collision

Quote (3DDave)

The caps on the Forth Road suspension bridge do not appear to provide enough distance for the overhang of a ship.

They are adequate for the typical ships which go upstream of the bridges, designed in the late 1990s and the shipping traffic hasn't significantly changed since then. The original bridge piers were considered strong enough for ship impact, with the upgraded defences being specifically for the expected overhang of ships using the river. The ports upstream are quite small, compared to the massive container ports elsewhere, and the river channel is relatively narrow and shallow. The exception is the Queen Elizabeth class carriers, but they are maneuvering slowly at that point and have tugs to assist them.

RE: Baltimore Bridge collapse after ship collision

The benefit of an explosive approach is workers can detonate it from a safe distance, vs trying to support workers while they manually cut the steel components. I assume there is a lot of experience regarding charge sizeing and safe distances, based on taking down buildings, tall antennas, etc. Lesser of a couple evils.

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

A few minutes ago I saw a live shot on CNN where someone was using a cutting torch on part of the bridge truss that's away from the ship.

RE: Baltimore Bridge collapse after ship collision

CDI have plenty of experience using shaped charges to chop up steel truss bridges into little pieces.

RE: Baltimore Bridge collapse after ship collision

The cutting torches could simply be where they're selectively weakening the structure so as to facilitate the eventual demolition using shaped charges. There are salvage/demolition companies with that expertise, to say nothing of the Corp of Engineers.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: Baltimore Bridge collapse after ship collision

I'm not caught up, but I did find what I was looking for, it wasn't a tug captain, it was a harbour captain, I didn't quite remember it. But they did blame him for quite a while.

https://www.latimes.com/archives/la-xpm-2002-sep-0...

RE: Baltimore Bridge collapse after ship collision

I used to drink coffee every afternoon with a retired demolition contractor.
He described removing a collapsed bridge that was blocking a major waterway.
Divers placed shaped charges on the structure..
After the first set of charges were detonated they got a frantic visit from the operators of a nearby underground mine.
Subsequent charges and detonations were coordinated with the mine operators.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Baltimore Bridge collapse after ship collision

Seems the crazy Dane that I know, and was doing the Suez grounding is on the job with SMIT.

Seems there is a HP gas line under it all.

RE: Baltimore Bridge collapse after ship collision

OFFICIAL SITE FOR INFORMATION REGARDING THE FRANCIS SCOTT KEY BRIDGE RESPONSE LINK

Demolition started Saturday
A large diameter high pressure gas transmission line (BG&E) was found to be very close to or underneath of the grounded ship, this has delayed attempts to Salvage the MV Dali



Baltimore Bridge Collapse 2024 Live | Baltimore Bridge Operations | Baltimore Bridge News LIVE |N18L CNN-News18 LINK to live video

Crews work to lift Baltimore bridge debris; officials eye temporary channel around collapse site WTVR CBS 6 LINK to video

Salvage at the Baltimore collapse site of the Francis Scott Key Bridge is well underway.
Minorcan Mullet LINK to video

Demolition Work Begins On The Francis Scott Key Bridge
John Konrad (gCaptain)
March 30, 2024
https://gcaptain.com/demolition-work-begins-franci...

RE: Baltimore Bridge collapse after ship collision




Australia's icebreaker Nuyina
'hit' Tasman Bridge multiple times during computer simulations
(abc.net.au/news/icebreaker-nuyina-hit-hobart-tasman-bridge-in-modelling/103158228)

RE: Baltimore Bridge collapse after ship collision

Quote (Richard Baum)

Australia's icebreaker Nuyina
'hit' Tasman Bridge multiple times during computer simulations
(abc.net.au/news/icebreaker-nuyina-hit-hobart-tasman-bridge-in-modelling/103158228)

And to finish that brief tangent topic, that bridge has very pertinent history on why they don't want big ships near it! (A smaller bridge, city and port so the economic effects weren't nearly as widespread, but still a big deal for the locals at the time.)


RE: Baltimore Bridge collapse after ship collision

MJCronin
Sr. Process Engineer

RE: Baltimore Bridge collapse after ship collision

MJCronin (Mechanical) How can I turn on ability to do a reply here in eng-tips ?
Looks like the priorities/objectives have been altered. They are currently using a cutting torch to clear the bridge away from the cargo ship, so smaller ships that can still use the shallower part of the channel, can resume operations.

https://www.voanews.com/a/baltimore-bridge-being-c...




Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

This website is something like 30 years old and probably hasn't been updated. This is not Reddit. There is no reply feature.

RE: Baltimore Bridge collapse after ship collision

Quote (KevinK2)

How can I turn on ability to do a reply here in eng-tips ?
Use the 'Quotes' tool in the toolbar that looks like a person with a cartoon quote bubble above the head.

Brad Waybright

The more you know, the more you know you don't know.

RE: Baltimore Bridge collapse after ship collision

Thanks for your input. I guess it's the ability to Quote another's post that I can't find. I've been off this site for over a year, and that quote option disappeared.


Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: Baltimore Bridge collapse after ship collision

2

Quote (RoopinderTara)

Can I quote you in an article?

In the interest of journalistic integrity of your organization, no you may not. I'm a no name on the internet. Why would you quote me? If you want to use that idea, go for it.

As for replying...the quotes call attention to what was said for the sake of context, but it's not a reply in the modern sense of internet discourse. A 'reply' uses an @ tag or sub-thread to tie the reply directly to the original statement and/or call attention to the person who made the comment by an email or a notification on the page (so they don't have to scroll through the entire thread). This forum has nothing like that to my knowledge.

RE: Baltimore Bridge collapse after ship collision

thanks again John R. Baker,

Torch cutting the beams continues, north of the ship location. In the past I noticed they have used robotic cutting torches, with their base resting on a barge, and operated by remote workers in a lift bucket. This could be useful when the cutting is at the ship location.

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

Quote (phamENG)

In the interest of journalistic integrity of your organization, no you may not.

It seems like a reasonable request, and if it is non-sensical given the anonymity, it still reflects well on the requestor for being courteous where none is required.

Going to take action if the quote is published anyway?

RE: Baltimore Bridge collapse after ship collision

I do appreciate that they asked. But the fact that they would want to quote a random person whose credentials cannot be verified does not reflect that well.

Would I take action? Really? Why would anyone waste the time or resources to do that? I told them to use the idea - that's all it is.

RE: Baltimore Bridge collapse after ship collision

Quote (MJCronin)

A reminder that Elmo is not an engineer, has never designed or built a bridge, hasn’t invented anything and uses his apartheid wealth to buy up other peoples work and pass it off as his own.

I just want to push back on this a bit. Elon Musk has been at the helm of - and in the weeds making design decisions at - premiere engineering organizations that are moving the state of the art forward across several industries.

How is he not an engineer?

RE: Baltimore Bridge collapse after ship collision

He is a monied entrepreneur. Engineers perform calculations to make predictions of future performance. Entrepreneurs pay engineers and make demands for future performance. Rare is the combination of an individual successful at both. Making demands is a separate decision process from engineering.

I doubt that Musk can install a battery into a TV remote the right way around, much less contribute to designing a phased array antenna to interoperate with a satellite constellation.

RE: Baltimore Bridge collapse after ship collision

Quote (3DDave)

He is a monied entrepreneur. Engineers perform calculations to make predictions of future performance. Entrepreneurs pay engineers and make demands for future performance. Rare is the combination of an individual successful at both. Making demands is a separate decision process from engineering.

I doubt that Musk can install a battery into a TV remote the right way around, much less contribute to designing a phased array antenna to interoperate with a satellite constellation.

I will push back a bit as well. It is one thing to point out EM's uninformed takes (this bridge for example or his cave submarine or even the highly improbable view that we will ever live on Mars). But he has a degree in physics and is also a programmer and a gamer so being all those things myself I can say that your ad hominen is just wrong and says more about your own bias. I mean I really wonder about your motivations and associations given that you are obviously experienced.

EM will be awarded an honorary degree in engineering if he hasn't already been for his direction of SpaceX, Tesla, and Starlink which not only persist today but dominate because of his personal involvement in day to day operations, vision, and probably design direction as well.



RE: Baltimore Bridge collapse after ship collision

Musk has a bachelor's degree in physics and economics, not engineering.

He does attract an interesting crowd, but the management of SpaceX is famous for taking measures to keep him away from the engineers.

RE: Baltimore Bridge collapse after ship collision

[quote 3DDave but the management of SpaceX is famous for taking measures to keep him away from the engineers.
/quote]

How about your source?

A friend's cousin is an engineer working at SpaceX for Musk, and he has nothing but praise for his visionary boss whom he is frequently conversing with. To assume he knows nothing technical is just assumption.

Having been a board certified professional mechanical enginnering consultant for 35 year, this video clearly shows that no engineeering degree is necessary for this man. The hows & whys of the improvements of the Raptor thrust engines, stages 1-3, per his vision for improvement:
https://www.youtube.com/watch?v=E7MQb9Y4FAE

But his populating Mars vision/effort is a bust, imho.

Off Topic Apology



Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

My grandpa was a college dropout that worked as a QA engineer at Aerojet on the Minuteman 3 project. It's not so common today but in the past one could become an engineer without an engineering degree.

RE: Baltimore Bridge collapse after ship collision

Quote (TugboatEng)

My grandpa was a college dropout that worked as a QA engineer at Aerojet on the Minuteman 3 project. It's not so common today but in the past one could become an engineer without an engineering degree.

You still can and many do. Plenty of states would issue him (*Elon) a PE license if he bothered to apply.

RE: Baltimore Bridge collapse after ship collision

He did apply... He was a QA engineer for Aerojet's solid fuel rocket program. He got recruited out of college by Bechtel before he graduated.

RE: Baltimore Bridge collapse after ship collision

2

Quote (3DDave)

He is a monied entrepreneur.

He is that, no doubt.

Preface: I'm no fan. I think his rash public takes on all manner of things demonstrate a remarkable level of arrogance and simultaneously a remarkable lack of self awareness..

With that said, I have been in very detailed technical meetings with Musk- in my past life in the robotics and process automation industries, I worked at a company that sold a great deal of equipment to Tesla. We developed several custom machines for them, and Musk frequently sat in on technical meetings as we were developing processes and debugging prototype builds.

It was very clear from the first meeting that Musk had come prepared, and was well versed enough in the technical issues we were resolving to not only understand clearly what we were talking about, but also to ask intelligent questions, make very detailed technical suggestions, and provide clear direction on the path he envisioned from prototype to deployment. He also listened well, and deferred to our engineers when they were able to back up their opinions with data. Precisely what I would expect from a highly effective engineering manager. In my personal experience he demonstrated a very strong understanding of engineering process statistics, material science, process automation programming, machine design for cost effectiveness, the list goes on. He was an expert at nothing, but was at least fluent in just about everything.

You can say all you want about his persona and I won't disagree, but it's a fact that he has an engineering mind.

RE: Baltimore Bridge collapse after ship collision

2
To the outside public he has done an exceptional job of hiding his engineering prowess. I'm a bit influenced that his PayPal windfall was the result of being dragged into a deal and not his business acumen.

https://en.wikipedia.org/wiki/PayPal#Early_history

I had some respect early on for his apparent willingness to camp out in the Tesla factory so that decisions, good or bad, could be made and judged for effectiveness in short order, a big advantage in cutting the management jungle.

I liked that he defended the SpaceX engineers after their Thai cave rescue contribution was questioned, though he turned that into a PR debacle.

He seemed more an Edison type - able to create an inventive organization by finding disaffected brilliant engineers who needed the funding to get enough traction, but damn if something seems to have happened to drain all that enthusiasm straight to the toilet for me.

From the outside it seems like his progress isn't the result of a great understanding and is, instead, more the result of just banging against a problem with a lot of money and other smart people until it is solved.

The launch platform, a well understood tech for example, that was literally blown to pieces by the rocket exhaust, damaging the rocket, seems like a great example of that. Is there going to be a breakthrough in flame trench technology? Or that tunnel under Las Vegas? Or the evacuated tube-train? Or brain research?

It's tough to reconcile these with engineering brilliance and it fits better that he has a really good memory (and has investors with a shared interest) that covers his moderate common sense. In his explanation of cavitation in that video it came across to me as a ChatGPT output rather than an expression of fundamental understanding.

I don't include his Twitter to X conversion - he has enough FU money and he wanted to screw a large number of people and did so; no engineering was part of that decision so it's not something I consider. It would have been nice to pay his bills, but the damage to Twitter isn't a great loss.

Lucky guy, has done some very interesting things; has made a huge fortune and made others wealthy as well without going out of his way to do so using some vast deceit (looking at Theranos and Wall Street manipulations) but I don't feel like he'd be able to run the numbers on a design or do more than a rough outline of a systems specification.

"a highly effective engineering manager" is exactly where I would peg him; just not a highly effective engineer.

RE: Baltimore Bridge collapse after ship collision

Quote (3D Dave)

"a highly effective engineering manager"
are rare. I have worked with a few. It is not a skill set that occurs with a non engineer MBA (opinion). Engineers that take the MBA class after being an effective engineer with responsible charge are more likely to be effective engineering managers.

I have never met Mr Musk, and given geography am unlikely to do so. From afar I see both successes and failures both fueled with lots of money. I also see a personality that is either admired or hated.

I think colonizing Mars is possible eventually, not likely in my or his lifetime, but the path will include many interesting and useful discoveries.

Now lets get back to unstopping the Port of Baltimore.

Port of Baltimore, Baltimore, Maryland USA | StreamTime LIVE

RE: Baltimore Bridge collapse after ship collision

https://www.facebook.com/USACEBaltimore


Oh yeah, just lift that twisted mess up, brush off the mud, send it to Bubba's alignment shop, and set it back in place so the real inspectors and engineers can certify its safety in 6 months time. Should be just as easy as colonizing Mars.


RE: Baltimore Bridge collapse after ship collision

Quote (It's not so common today but in the past one could become an engineer without an engineering degree.)


Gord Gilbert, one of the finest Architects I knew, who was project architect on the airport at Kathmandu, the Cornwall Centre, and the Toronto Skydome had a basic technical degree from Ryerson, in Toronto. He was world class.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

That image appears to be a composite of an above water lidar scan and a below water sonar scan. The depth in the channel is 50 feet deep, giving a sense of scale as to the size of the parts that are still in the air.

The detail in the sonar portion is impressive.

RE: Baltimore Bridge collapse after ship collision

Genuinely impressive - although the difference in resolution (<2 ft in the sonar portion) coupled with the yellowish colouration makes it look as if the structure has been underwater for twenty years.

That's a mess.

RE: Baltimore Bridge collapse after ship collision

[quote 3DDave "The depth in the channel is 50 feet deep"/quote]

The recently opened channel has a usable depth of 11 ft, and a second one will be 15 ft deep. For comparison, the wrecked Dali container ship has a maximum draft of 49 ft. https://en.wikipedia.org/wiki/MV_Dali

Is there a potentially deep part of the channel, ~closer to the ship, that could allow much more depth than 11 or 15 ft? I could not find an image showing variations in the channel depth at the bridge locations, like a contour map.

PS: still need help on quoting posts

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

copy / paste / select pasted material / click quote button (little person with balloon over their head) and fill in name.

Also - the "[" and "]" need to be on both ends of each "quote" and "/quote" to work.

RE: Baltimore Bridge collapse after ship collision

Did the ship rise up as it hit the shallow water lifting the bridge off its support and is now stuck fast?

I think in that original video you can actually see the ship lift a bit before it collides with the concrete bridge support.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Baltimore Bridge collapse after ship collision

I doubt that they will want to allow any large ships through the deep channel while Dali is still there, even if they manage to clear most of the bridge. Although she's well to the side of the channel, she is still restricting the available width of deep channel, it's increased risk. Additionally, they probably don't want the wash from large ships acting on the various work barges and support vessels or Dali when she's sitting on the gas pipeline.

They need to clear both the wreckage and the ship before it's safe to resume normal navigation in the main channel, in my opinion. The deep channel is only approximately 1-2 cables wide (0.1-0.2nm), which is not a lot for big ships. It's roughly 2 cables wide between the dolphins, but they sit outside the channel.

Here are the NOAA charts covering the area (12281 gives you the detail, the others are for anyone who wants to look beyond the harbor):

12273 - CHESAPEAKE BAY, SANDY POINT TO SUSQUEHANNA RIVER
12278 - CHESAPEAKE BAY, APPROACHES TO BALTIMORE HARBOR
12281 - BALTIMORE HARBOR

Soundings (depths) are in feet above MLLW (the mean lowest tide over time), but there's not much tidal range. The largest tidal range at Fort McHenry is only around 1.7 feet.

RE: Baltimore Bridge collapse after ship collision

Murph 9000 "I doubt that they will want to allow any large ships through the deep channel while Dali is still there ... "

Excellent depth map of this channel. It shows just 33 ft depth just outside of the supports for the channel. The maximum draft for the Dali is 49 ft, and it's possible it's bottomed to some degree.

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

I brought in the available lidar data into CAD last week. Here is a screenshot of the contours referenced to NAVD88 (US FEET). There's a deep depression just northwest of the bridge pier that I'm assuming is part of that utility channel cutting SW to NE.

RE: Baltimore Bridge collapse after ship collision

Looks like the NOAA charts don't show the exact location of the gas pipeline. Just a generic "pipeline and cable area":

RE: Baltimore Bridge collapse after ship collision

Quote (dold (Structural)
Looks like the NOAA charts don't show the exact location of the gas pipeline. Just a generic "pipeline and cable area":)


It is my understanding that the little boat near the bow of the Dali is the survey crew that was sent there on Tuesday afternoon to plot the exact location of the pipeline in relation to the ship. It makes sense that the gas line would be on the opposite side of the "cable and pipeline area" as the power lines. Image taken from the New York Times.


RE: Baltimore Bridge collapse after ship collision

Is the cylindrical item to the left side of Nukeman's photo one of the protection dolphins? If so, in comparison to the Dali, it looks like it had little chance to have been effective for any true protection for the bridge against a ship this size.

RE: Baltimore Bridge collapse after ship collision

Proceedure to transit under the Tasman Bridge was or still is for years after it was repaired!
1/: block both sides and all lanes with police cars for the transit duration as one car went past the cars stopped on bridge using the wrong side of road and was unable to stop.
2/: All ships need to maintain enough speed to enable steerage during transit.
The big question always will be? If the Dali had maintained ahead power with the ability to maintain steerage would it have missed the bridge.

RE: Baltimore Bridge collapse after ship collision

Yes, unless you believe the conspiracy theories.

RE: Baltimore Bridge collapse after ship collision

Quote (Richard Baum)

If the Dali had maintained ahead power with the ability to maintain steerage would it have missed the bridge.

This isn't a question at all, let alone 'the big question'. All indications are that prior to loss of power, the ship was operating and navigating in a completely normal way. The harbor pilots aboard would not have piloted the boat into the bridge pier, period.

This was not an intentional act. Anyone who thinks it was, is wrong.

RE: Baltimore Bridge collapse after ship collision

The Dali was most likely operating full astern with the anchor dropped.
this means that it would yaw to starboard with a loss of steerage.
If the engine had been slow ahead and anchor up the ship would have maintained stearage and missed the bridge.

RE: Baltimore Bridge collapse after ship collision

Anybody else seen the suggestion that tidal flow ebbing out of the Curtis Bay Channel acting on the stern of Dali with steering and propulsion both inactive throughout would be sufficient to explain the change of heading?

RE: Baltimore Bridge collapse after ship collision

zeusfaber (Military) ... tidal flow ebbing out of the Curtis Bay Channel acting on the stern ...

More likely wind, per gcaptain.com :

"The emergency generator does not connect to propulsion but should support steering and navigation systems but the ships heading appears to have been pushed off course by the wind directly into the support column."

https://gcaptain.com/ship-lost-control-before-hitt...

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

Today's paper stated the ship was firmly grounded on the bottom. This is consistant with an estimate made of the force needed to slow the ship to a stop of 12 million newtons, or 2.7 million lbf. Tug boats are keeping the ship's tail from wagging.
https://www.nytimes.com/interactive/2024/03/28/ups...

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

Quote (SwinnyGG)

This was not an intentional act. Anyone who thinks it was, is wrong.

You are guessing. Saying, rather, that we don't know does not compromise an investigation of cause.

RE: Baltimore Bridge collapse after ship collision

charliealphabravo: "You are guessing. Saying, rather, that we don't know does not compromise an investigation of cause."

It's not guessing if you have paid specialists to investiage for any act of sabotage, tax payer funded FBI:
https://www.youtube.com/watch?v=Ws7pOHGV3dQ


Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

2

Quote (charliealphabravo)

You are guessing. Saying, rather, that we don't know does not compromise an investigation of cause.

It's not a guess. Believe what you want, but a belief that this was some complicated conspiratorial plot is pure fantasy.

RE: Baltimore Bridge collapse after ship collision

Suspect they will decide that the boat should never have left port with the technical issues it had. But the big bosses didn't want to pay port charges.

Then Dane has been saying they have no chance of shifting it until they get the bulk of the cargo off. It well and truly rammed into the bottom up and over geological features and hooked.

RE: Baltimore Bridge collapse after ship collision

Quote (KevinK2)

It's not guessing if you have paid specialists to investiage for any act of sabotage, tax payer funded FBI:
https://www.youtube.com/watch?v=Ws7pOHGV3dQ

I listened to the video. According to the FBI there is no indication of terrorism linked to this incident.
I suspect that this is just standard operating procedure. When something like this happens, it is thoroughly investigated. But I would not see FBI's involvement as an indication of anything intentional in this case.

RE: Baltimore Bridge collapse after ship collision

4
This report describes what happened 50 years ago.
I am 79 and was the 4th engineering officer on that ship.(I had gone on leave 12days before) my replacement was killed.
The bridge was the about the same size. 4 lanes
The ship was carried 10,000 tons of ore

The Dali is about 10 times larger

When the Dali hit the bridge the anchor had been down and it was going full speed astern (lots of black smoke) completely out of control.

If the Master and pilots had not dropped the anchor and instead proceeded slow ahead to maintain stearage the Dali would have passed under the bridge

From Wikipedia, the free encyclopedia
Tasman Bridge disaster

Tasman Bridge from east following collision, 1975
Date 5 January 1975
Time 9:27 p.m. (AEDT)
Location Hobart, Tasmania, Australia
Coordinates 42°51′53″S 147°20′48″E
Type Accident
Cause Bulk carrier Lake Illawarra collision with a bridge pier
Deaths 12

The Tasman Bridge disaster occurred on the evening of 5 January 1975, in Hobart, the capital city of Australia's island state of Tasmania, when the bulk carrier Lake Illawarra, travelling up the Derwent River, collided with several pylons of the Tasman Bridge and caused a large section of the bridge deck to collapse onto the ship and into the river below. Twelve people were killed, including seven crew on board Lake Illawarra, and the five occupants of four cars which fell 45 metres (150 ft) after driving off the bridge. Hobart was cut off from its eastern suburbs, and the loss of the road connection had a major social impact. The ship's master was officially penalised for inattention and failure to handle his vessel in a seamanlike manner.

The collision occurred at 9:27 p.m. Australian Eastern Daylight Time (UTC+11:00) on Sunday 5 January 1975. The bulk carrier Lake Illawarra, carrying 10,000 tonnes (11,000 short tons; 22,000,000 lb) of zinc ore concentrate, was heading up the Derwent River to offload its cargo to EZ Industries' Risdon Zinc Works, upstream from Hobart and about 3 km (1.9 mi) from the bridge. The 1,025 m (3,363 ft) long main viaduct of the bridge was composed of a central main navigation span, two flanking secondary navigation spans, and nineteen approach spans. The ship was off course as it neared the bridge, partly due to the strong tidal current but also because of inattention by the ship's master, Captain Boleslaw Pelc.[1] Initially approaching the bridge at eight knots (15 km/h; 9.2 mph), Pelc slowed the ship to a 'safe' speed. Although Lake Illawarra was capable of passing through the bridge's central navigation span, Pelc attempted to pass through one of the eastern spans.

Despite several changes of course, Lake Illawarra proved unmanageable due to having insufficient steerage way. In desperation Pelc ordered 'full speed astern',(which was about 10% of forward speed) at which point all control was lost. The vessel drifted towards the bridge midway between the central navigation span and the eastern shore, colliding with the pile capping of piers 18 and 19, bringing three unsupported spans and a 127-metre (417 ft) section of roadway crashing into the river and onto the ship's deck. Lake Illawarra listed to starboard and sank within minutes a short distance to the south, in 35 metres (115 ft) of water. Seven crew members were trapped and drowned. The subsequent Court of Marine Inquiry found that Pelc had not handled the ship in a proper and seamanlike manner, and his certificate was suspended for six months.[2]

As the collision occurred on a Sunday evening, there was relatively little traffic on the bridge. While no cars were travelling between the 18th and 19th pylons when that section collapsed, four cars drove over the gap, killing five occupants. Two drivers managed to stop their vehicles at the edge, but not before their front wheels had dropped over the lip of the bridge deck. One of these cars contained Frank and Sylvia Manley in their Holden HQ Monaro.

Sylvia Manley: "As we approached, it was a foggy night ... there was no lights on the bridge at the time. We just thought there was an accident. We slowed down to about 40 km/h (25 mph) and I'm peering out the window, desperately looking to see the car ... what was happening on the bridge. We couldn't see anything but we kept on travelling. The next thing, I said to Frank, "The bridge is gone!" And he just applied the brakes and we just sat there swinging.[3] As we sat there, we couldn't see anything in the water. All we could see was a big whirlpool of water and apparently the boat was sinking. So with that, we undid the car door and I hopped out."[4]

Frank Manley: "[Sylvia] said "The white line, the white line's gone. Stop!" I just hit the brakes and I said "I can't, I can't, I can't stop." And next thing we just hung off the gap...when I swung the door open, I could see, more or less, see the water...and I just swung meself towards the back of the car and grabbed the headrest like that to pull myself around.[4] There's a big automatic transmission pan underneath [the car] – that's what it balanced on."[3]

The other car contained Murray Ling, his wife Helen and two of their children. They were driving over the bridge in the east-bound lanes when the span lights went out: 'I knew something bad must have happened so I slowed down'. Ling then noticed several cars ahead of him seemingly disappear as they drove straight over the edge, so he slammed his foot on the brakes. He stopped the car inches from the drop. A following car, caught unaware by the unexpected stop, drove into the rear of Ling's car, pushing its front wheels over the breach. He, too, eased himself and his young family out of the car, then stood horrified as two other cars ignored his attempts to wave them down, raced past (one of which actually swerved around to avoid him), and hurtled over the edge into the river. A loaded bus full of people swerved and skidded, slamming into the side railings after being waved down by Ling.[5]

Emergency response
Private citizens living nearby were on the scene early, even before Lake Illawarra had sunk. Three of these were Jack Read in his H28 yacht Mermerus; David Read in a small launch; and Jerry Chamberlain, who had their boats moored in Montagu Bay close by. These and others, and many shore-based residents, were responsible for saving many of the crew from Lake Illawarra. Those in small craft acted alone in very difficult circumstances with falling concrete, live wires, and water from a broken pipe above, until the water police arrived on the scene. A large number of other organisations were involved in the emergency response, including police, ambulance service, fire brigade, emergency management agency, marine board, Royal Hobart Hospital, the Hobart Tug Company, the Public Works Department, the Transport Commission, the HydroElectric Commission, the Hobart Regional Water Board, the Australian Army and the Royal Australian Navy. At 2:30 am, a fourteen-man Navy Clearance Diving Team flew to Hobart to assist water police in the recovery of the vehicles which had driven off the bridge. Two vehicles were identified on 7 January; one was salvaged that day and the second three days later. Another vehicle was found buried under rubble on 8 January.[citation needed]

A comprehensive survey of the wreck of Lake Illawarra was completed by 13 January. The divers operated in hazardous conditions, with little visibility and strong river currents, contending with bridge debris such as shattered concrete, reinforced steel rods, railings, pipes, lights, wire and power cables. Strong winds on the third day brought down debris from the bridge above, including power cables, endangering the divers working below.

RE: Baltimore Bridge collapse after ship collision

Quote (Richard Baum)

If the Master and pilots had not dropped the anchor and instead proceeded slow ahead to maintain stearage the Dali would have passed under the bridge
Maybe

Brad Waybright

The more you know, the more you know you don't know.

RE: Baltimore Bridge collapse after ship collision

2

Quote:

To the outside public he has done an exceptional job of hiding his engineering prowess. I'm a bit influenced that his PayPal windfall was the result of being dragged into a deal and not his business acumen.

EM is a huckster and egotist; he's promised full FSD "next year" for almost a decade now and still hasn't delivered. He knows more about manufacturing than anyone in the world.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Baltimore Bridge collapse after ship collision

Quote (Suspect they will decide that the boat should never have left port with the technical issues it had. But the big bosses didn't want to pay port charges.)


That was my first thought, when the boat was 'hung up' for electrical reasons.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

We don't really have any detail on the electrical problems reported at the dock. There's a world of difference between just tripping a couple of breakers supplying reefer units in the stacks, and something critical going on with the service generators or main switchboard.

RE: Baltimore Bridge collapse after ship collision

It was gen and shore hook up issues apparently.

Black ship for minutes

RE: Baltimore Bridge collapse after ship collision

2
Maybe

Brad Waybright

The more you know, the more you know you don't know.

correct.

the time has come to wait for the results of the inquiry

RE: Baltimore Bridge collapse after ship collision

Quote:

It was gen and shore hook up issues apparently.

Given that the ship lost power multiple times while under way, it would seem to be an incredible coincidence that shore power was also problematic. Occam's Razor would say that the ship had problems with power, both docked and under way.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Baltimore Bridge collapse after ship collision

Let's wait for the report and then play bingo. Here are ten things I predict the report will tell us. Let's see how many actually appear.

The ship went black because multiple things were broken.

Some of them them had been broken for a long time

On ships, something is always broken

Sometimes the stuff you know is broken stops you finding out that other stuff is broken too

In some ships, individual DGs fall off the board quite often

Because you don't as a rule mess around with equipment line-up while you're in confined waters, DG trips usually wait until a time when it doesn't really matter. You can come to depend on this.

The problems in port also happened because multiple things were broken

They fixed some stuff in port

What they fixed in port wasn't the stuff they didn't know was broken

If problems only manifest at a time of their own choosing, you can never be certain the stuff you fixed has cured them completely

All wild speculation. What else should be on the card?

RE: Baltimore Bridge collapse after ship collision

Quote:

If the engine had been slow ahead and anchor up the ship would have maintained stearage and missed the bridge.


The bow dragging bottom could have been why it turned into the bridge.

RE: Baltimore Bridge collapse after ship collision

Do remember, the ship browned out, it didn't just black out. This excludes a generator "trip". It seems more likely that a mechanical fault caused the DG(s) to lose speed and get into the under frequency roll-off curve of the voltage regulator. This also explains the black smoke.

RE: Baltimore Bridge collapse after ship collision

how is the electrics set up on these boats tug?

RE: Baltimore Bridge collapse after ship collision

DG = diesel generator/genset?

RE: Baltimore Bridge collapse after ship collision

i thought he was referring to a gear box type setup to the generator. But that's why I asked I don't know.

RE: Baltimore Bridge collapse after ship collision

2
Usually there are 3 switchboards. Two mains and an emergency. These power will loads on the ships.

All switchboards are inter-connected by bus tie breakers.

Critical loads are distributed amongst the switchboards. For example, each main switchboard supplies power to an engine cooling pump. The steering gear will have one power unit on a main SWB and the other on the emergency switchboard.

The bus tie breaker to the emergency switchboard has an under voltage trip. This breaker requires a key to reset that is carried only by the chief engineer.

There are 3+ generator sets which can be paralleled.

Each generator circuit breaker has a reverse power relay to prevent motorizing.

The switchboards have automatic load shedding for non-essential loads so the ship should be able to run on a single generator set.

The main engine cannot run continuously on the emergency generator. I was mistaken earlier when I said that. The generator set is too small to power the necessary pumps.

The large amount of black smoke could have indicated the engine was still running but the power failure caused the auxiliary blowers to stop operating which may have starved the engine for air
.I have never operated a slow speed diesel, I don't know how much load is required before the turbochargers can supply sufficient charge air. I did all of my training on steam.

RE: Baltimore Bridge collapse after ship collision

Quote (TugboatEng)

Usually there are 3 switchboards. Two mains and an emergency ...

Great input. alleged MV Dali drives/generators:

Dali is propelled by a single low-speed two-stroke crosshead diesel engine coupled to a fixed-pitch propeller. Her main engine, a 9-cylinder MAN-B&W 9S90ME-C9.2[9] unit manufactured by Hyundai Heavy Industries under license, is rated 41,480 kW (55,630 hp) at 82.5 rpm.[2] Her service speed is 22 knots (41 km/h; 25 mph).[5]

For maneuvering in ports, Dali has a single 3,000 kW (4,000 hp) bow thruster. Electricity is generated onboard by two 3,840 kW (5,150 hp) and two 4,400 kW (5,900 hp) auxiliary diesel generators.[4]

https://en.wikipedia.org/wiki/MV_Dali

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

Alistair, I hope my comment on DG did not appear as a dig to you. I was asking for confirmation on the DG acronym since jargon is often used but no definition provided for those, like me who are not familiar.

RE: Baltimore Bridge collapse after ship collision

That looks like a fairly standard big plant switchboard system.

The devil is in the detail of what is on which board and which systems are protected with UPS and which generators are linked to which board.

The fact all the lights went out looks pretty bad because it strongly implies the emergency board went down as well. One or more of those generators is usually then designated as the emergency board feed, but it takes 10 to 15 seconds to get up to speed and stabilised before the breakers drop in and the lights come back on.

However a lot of systems won't like suddenly being deprived of power and can trip as well on restart. Also depends on how well they've maintained the UPS on the control system. Not unknown for the batteries to be dead after 10 to 15 years of doing nothing.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Baltimore Bridge collapse after ship collision

Far from it Brian.

I know the aviation acronyms which there are thousands of. Sometimes they use the same letters and you have to work out the subject ie aircraft system, NAV, ground handling etc

Marine we are in the same league of knowledge of them ie pretty much zero in my case.

RE: Baltimore Bridge collapse after ship collision

FYI, for those who are interested, there is a Chinese (I know, might not be the best source, obviously download at your own risk) ship simulator/trainer that one can install and experiment with, located here: http://www.ers3d.com/home/index.do

It is free for some of the ship models, but requires registration (I used one of my throwaway email addresses).

It seems fairly comprehensive, although some of the ships simulated seem to be broken/incomplete (I've been trying for days to get the entire AC electrical system up on their "Steam Turbine Powered LNG Ship ERS," for instance. I'm at the point of suspecting that there is a bug in this one, but I could be wrong).

Anyways, they have a simulator for "ULCS (10020 TEU) ERS" that I'm assuming is SOMEWHAT (basically same size class) similar to the ship in question, although I'd expect that the exact wiring details/installed equipment would vary per individual ship.

In this simulation, the only lighting circuits on the emergency bus are some engine room emergency lights. The main lighting panel (seems to be LVMSB220V) derives it's power from a 440v normal power bus, through a 220v transformer (actually a pair for redundancy).


You can drill down to each panel/etc to see and control/simulate the actual breakers, so the above diagram is only a top-level view.

Detail from the 440v emergency switchboard:


Detail from the 220v emergency switchboard:


Detail of half of the Normal 440v switchboard:


Of course, the question is, how close is this to the layout of the MV Dali?

RE: Baltimore Bridge collapse after ship collision

Quote:

I don't know how much load is required before the turbochargers can supply sufficient charge air. I did all of my training on steam.
Small diesel engines,ie:trucks, diesel generators, pumps and compressors:
Don't confuse the action of a turbo charger with the action of a two stroke scavenging blower.
The engines act as NA, Naturally Aspirated at idle. As load is applied, the turbo spins up.
Modern diesel engines limit the fuel charge when accelerating so as to avoid overfueling and black smoke until the turbo spins up. Early engines used a mechanical aneroid valve which could easily be defeated.
The result was a cloud of black smoke until the turbo had spooled up and was supplying enough air for the fueling rate.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Baltimore Bridge collapse after ship collision

Modern slow speed diesel have electric blowers for scavenging during starting and light load operation.

Remember, these are 2-stroke engines. They don't have intake or exhaust strokes so they require an air pump. That might be the underside of the piston and reed valves (Sulzer RND) or electric blowers.

RE: Baltimore Bridge collapse after ship collision

Re: Musk Engineer Discussion.

To me, the ultimate mark of someone who is deploying engineering expertise is the ability to generate a successful outcome.

While generating a successful outcome in the technical realm depends on being able to deploy useful technical hard skills (engineering), it also requires the synthesis of many others soft ones (project execution, finance, leadership, decision making, etc.). I award almost no points to those who beat their chest trumpeting their hard skills yet are unable to harness the all forces needed generate a successful outcome. Why build a ship if it cannot harness the wind?

Take the Roeblings. Engineers, right? Do you think the Brooklyn Bridge would have gotten built if they couldn't have also manufactured the cables themselves? What came first, the ability to create a company that manufactured wire or the ability to engineer designs that utilized it?

On Plant Earth, there is no one else that I'm aware of that has been able to generate as many successful engineering-related outcomes as Musk. Yes, there are legions of engineers, managers, financiers, and the like in the trenches at the organizations he is a part of that carry 99% of the load toward those successes. But I'd say that there is a 99% chance that Earth wouldn't have independently generated those companies and outcomes without him.

He's aware, curious, intelligent, ethical, filled with useful hard and soft skills, and is best in class in generating successful outcomes. If that's not the formula for engineering expertise, then what is?



RE: Baltimore Bridge collapse after ship collision

Re: 2020s Baltimore Cleanup vs. Potential 1940s NYC Cleanup.

How does our ability to cleanup a bridge collapse in a harbor compare now to the 1930s/1940s?

I recall one of the reasons why Robert Moses' Brooklyn Battery Bridge was shot down in favor of a tunnel was the risk of a collapse blocking the Brooklyn Naval Yard. (And of course his feud with Roosevelt and the destruction of Battery Park for a bridge, etc.)

As I'm watching Baltimore work to clear a channel in a matter of weeks, I'm just curious how long it would have taken for NYC to clear a potential WWII-era collapse of a Brooklyn-Battery Bridge (if it was built and then attacked).

Does anyone in the Marine Engineering space have a feel for that?

https://www.nypap.org/preservation-history/brookly...

RE: Baltimore Bridge collapse after ship collision

Re: Musk Engineer Discussion.

You can criticize Musk all you want for lack of engineering knowledge, but I believe Boeing would be in a much better place with him at the helm.

Brad Waybright

The more you know, the more you know you don't know.

RE: Baltimore Bridge collapse after ship collision

Quote (Wiki)

For maneuvering in ports, Dali has a single 3,000 kW (4,000 hp) bow thruster. Electricity is generated onboard by two 3,840 kW (5,150 hp) and two 4,400 kW (5,900 hp) auxiliary diesel generators.
I haven't seen any speculation concerning the bow thruster.
A motor failing by turn to turn shorts may still pass a megger test.
It will, however, quickly progress to total failure.
There is speculation concerning the relative ineffectiveness of the rudder without propulsion.
A progressively failing phase in the thruster motor could easily make one or possibly two of those auxiliaries "Roll Coal".

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Baltimore Bridge collapse after ship collision

Interesting youtube...

https://www.youtube.com/watch?v=2Wim-_Q_59o

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

Can't imagine the bow thrusters were still running by the time the ship was established in the channel and making 8 kt - or that they'd have that much effect even if they were.

RE: Baltimore Bridge collapse after ship collision

Just as important as the discussion about ensure ships operate safely in the confined space of a port, is the important issue of protecting bridges.

The requirements for the design of bridge pier protection exist - AASHTO Guide Specification and Commentary for Vessel Collision Design of Highway Bridges.

Sorry I do not have access to a free copy. This next document is an explanation of a program FDOT created to implement the calculations in the preceding document.

Basics of Vessel Collision; Stephen Fowler, PE and Matthew Kosar, PE

What does not seem to exist is a mandate to retrofit critical bridges.
Why the Chesapeake Bay Bridge is just as Vulnerable to Collapse from Ship Impacts as the Key Bridge; Casey Jones -

RE: Baltimore Bridge collapse after ship collision

Quote:

Can't imagine the bow thrusters were still running by the time the ship was established in the channel and making 8 kt - or that they'd have that much effect even if they were.
Admitted the efficiency will be much less when underway, but when the rudder is ineffective, ant help from the bow thruster may help turn the ship.
And a failing thruster could explain both the lack of turning effort and the black smoke. (rolling coal in red-neck speak)

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Baltimore Bridge collapse after ship collision

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Baltimore Bridge collapse after ship collision

The rudder was ineffective due to loss of electrical power...

RE: Baltimore Bridge collapse after ship collision

Quote (waross (Electrical))


If you are going to post a picture, it would be nice if you could include a bit of commentary so that we might have some idea of the point you are trying to make, especially when the picture is of an entirely different ship. (hint: the Dali only has one bow thruster)
Also, speculating about a faulty bow thruster when there is no evidence or even reporting that there was any attempt to use the bow thruster during this mishap seems like a pointless exercise to me. There was certainly no reason to be using the bow thruster between the time it left the dock and got turned around, and when it began showing signs of an electrical problem.


RE: Baltimore Bridge collapse after ship collision

Picture from Wiki.
General idea of the arrangement of bow thruster(s).
I think it is strange that there has been no mention of the bow thruster, used, unused or failing.
A failing bow thruster could explain the so far unexplained electrical problems and the brown out and the black smoke.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Baltimore Bridge collapse after ship collision

This link has some useful information on bow thrusters.
The Essential Guide to Bow Thruster Construction and Functionality - ByMohit January 30, 2024

Some specifics

Quote (https://en.wikipedia.org/wiki/MV_Dali)

For maneuvering in ports, Dali has a single 3,000 kW (4,000 hp) bow thruster. Electricity is generated onboard by two 3,840 kW (5,150 hp) and two 4,400 kW (5,900 hp) auxiliary diesel generator
This thruster most likely needs two of the service generators on line to reliably start. It could not be operated from the emergency bus or from one generator due to not enough generating capacity. The bow thruster is interesting, but not in play for this event (my opinion). I was not able to find anything referencing the Dali's emergency generator size.

RE: Baltimore Bridge collapse after ship collision

At 8 knots the ship would not have been using its now thruster.

For those that are unaware of what an auxiliary blower is, this video has a short description at the beginning.

https://youtu.be/9uajoqlvIx0?si=bGEEQ5iaVFEA6ra7

RE: Baltimore Bridge collapse after ship collision

Quote (waross)


-> I haven't seen any speculation concerning the bow thruster.

Based on my limited research, a thruster is sized to maneuver the ship at low-idle speeds, as during docking proceedures, not to change the direction of the ship underway. When the drive was lost, limited linearized tracking data showed a 2 step direction change, with the ship increasingly veering off course. Still not clear as to why.

-> There is speculation concerning the relative ineffectiveness of the rudder without propulsion.

In an illusrated presentation, they showed the rudder operated directly behind the propeller and redirected the thrust it created off center to make a turn. Without the prop shaft working, the rudder would have little effect on the ship's path.

-> A progressively failing phase in the thruster motor could easily make one or possibly two of those auxiliaries "Roll Coal". Just an FYI, "Rolling coal (also spelled rollin' coal) is the practice of modifying a diesel engine to emit large amounts of black or grey sooty exhaust fumes—diesel fuel ..."

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

This ship is 2016 vintage. It has electronically controlled engines and should not roll coal under any load conditions except in the event of a mechanical fault such as a turbocharger failure.

RE: Baltimore Bridge collapse after ship collision

I suspect the thrusters propellers will stall trying to suck water in from a flow going at 8 knts going horizontal across a hole face.

RE: Baltimore Bridge collapse after ship collision

The hydrodynamics of the bow thrusters are probably a factor, but I think it's also a v-squared thing. You've got considerably more momentum at 8 knots compared to dead slow maneuvering in and out of a dock. The thruster is sized to provide enough energy for slow speed use. I'm not an expert on it, just thinking from first principles, and I think it's a bit like the steering tyres on a car, where the ability to redirect the momentum greatly diminishes with speed.

RE: Baltimore Bridge collapse after ship collision

Its fluids there must a cubed in there somewhere as well :D

But yes there will be that as well.

There is a theory that they teach in Europe apparently which is to turn the tug sideways so the broad side of the boat and kegg acts as a colossal brake but you need vectored thrust on the tug plus its structurally unsound afterwards.

RE: Baltimore Bridge collapse after ship collision

The focus here seems to be about the bow thrusters' ability to re-direct momentum. What if the thruster could simply push the bow out without affecting overall momentum? The ship might have struck more sideways with a deeper part and possibly a better outcome.

RE: Baltimore Bridge collapse after ship collision

Quote (stevenal)

.. thrusters' ability to re-direct momentum ..
Momentum is a vector quantity M = m * V , caps imply vector, and m = huge

So the bow thruster would work against a resistive, momentum based torque. That's why their use is only effective when V is near zero, as in docking.

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

Here's a call for action on bridge protection, mainly bigger dolphins and more of them, an article by our author and resident civil engineer/bridge inspector, Joshua Sadlock. I helped with some of the writing. Let me know what you all think.




Roopinder Tara
Director of Content
ENGINEERING.com

RE: Baltimore Bridge collapse after ship collision

Quote (RoopinderTara)

Here's a call for action on bridge protection, mainly bigger dolphins ...

By coincidence new 80ft dolphins are currently being installed nearby for Delaware Memorial Bridge over the Delaware River. The bridge is massive, and MV Ships travel under it to major ports in Philadelphia. Dolphin design details:

https://delawarelive.com/memorial-bridge-dolphins-...

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

I'm concerned that the dolphins can stop the ship but then tear into the hull in a way the overhanging portion still reaches the bridge pillars.

RE: Baltimore Bridge collapse after ship collision

That's ok. These ships are operating with very little under keel clearance. If you tear a hole into the hull and sink the ship it will likely end up only a few feet lower than it was when it was floating.

RE: Baltimore Bridge collapse after ship collision

Quote:

I'm concerned that the dolphins can stop the ship but then tear into the hull in a way the overhanging portion still reaches the bridge pillars.

I think that the article touches on that; the dolphins have to have some give, like crumple zones; ripping the the bottom out of a ship and sinking it isn't exactly a win-win.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: Baltimore Bridge collapse after ship collision

MV Dali had the hull torn open and did not sink because of it; sinking is not a problem that needs addressing. Refloating a ship that is a few feet lower in the water than normal isn't a huge problem and, as in this case, if it sinks because the ship was not seaworthy? Shug.

RE: Baltimore Bridge collapse after ship collision

Quote (3DDave)

MV Dali had the hull torn open and did not sink because of it; sinking is not a problem that needs addressing. Refloating a ship that is a few feet lower in the water than normal isn't a huge problem ...

This video opens with a view of the reinforced concrete support that the Dali hit. Soon the focus is on the part of the upper hull that was removed by the collision with the support. This shark-bite from the hull went below the deck, but not below the waterline. Don't know if the hull was opened below it, via other contact..

https://www.youtube.com/watch?v=sB1UwdFART8&t=...

Based on this image, the ship seems to be listing away from the impacted support. Most likely due to the massive part of the bridge hanging off that side, but less likely due to that side resting on the severed upper parts of the bridge support, now below the hull.

Link

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

It likely doesn't contribute much to the conversation but the bow of ship is likely hard on the bottom due to the weight of the bridge components laying across it, flooding not required.

This does put it in a severe hogging condition and, depending on tides, could fatigue and break the hull over time.

RE: Baltimore Bridge collapse after ship collision

Not a marine eng so dunno.

I noticed them/they moving cans off the front but that is likely on an as necessary basis. I've just come to believe that it will be refloated intact with most of the load in place. Does anyone have any insight regarding the cargo and Tug's comment?

RE: Baltimore Bridge collapse after ship collision

Crash energy management requires conjuring many fantasies making many assumptions about the collision. Real collisions rarely obey the fantasy assumptions.

In broad terms, the goal of CEM is to share the energy dissipation between the objects involved in the collision - in this case a ship and a "dolphin".

But a dolphin that would deform to absorb its share of a collision from a ginormous ship like the Dali would be effectively an immovable object for a smaller ship, which would cause the smaller ship to take the full force of the impact.

Conceptually, you could get around this challenge with many small dolphins. A small ship would engage with only a few, while larger ships engage with many. Then is becomes a problem of space.

CEM works reasonably well when everyone is working to the same fantasy standard. For example automobiles, where (in the US at least) there are defined sets of collision cases to design for.

RE: Baltimore Bridge collapse after ship collision

Quote:

where (in the US at least) there are defined sets of collision cases to design for.

That's mostly true, IIHS testing resulted in adding design cases to auto design; the offset collision case comes to mind. The makers complained that it wasn't part of the federal test suite, but eventually added it and tooted their horns about having it.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Baltimore Bridge collapse after ship collision

I snagged this picture off a news broadcast last week. It's an incredible mess they're dealing with, and it looks like the bow was just abraded away in the collision. That big block of concrete must be part of the bridge support. I'm surprised to see such a clean break on something so massive.

RE: Baltimore Bridge collapse after ship collision

This photo from earlier makes it pretty clear those towers were hollow section reinforced concrete. So OK in compression but not really very strong when hit by a ship.


Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Baltimore Bridge collapse after ship collision

Quote (MintJulep)

Conceptually, you could get around this challenge with many small dolphins. A small ship would engage with only a few, while larger ships engage with many. Then is becomes a problem of space.

As the ship channel is linear for about 12 miles (maybe 8 miles upstream in the harbor and 4 miles downstream on the ocean side), it seems that a line of many smaller dolphins could have been placed on the approach to the bridge supports. I know this means that ships have to go upstream and make a U-turn to enter the ship channel, but in this case, the dolphins seem to have been necessary.

RE: Baltimore Bridge collapse after ship collision

Baltimore Harbor and Channels 50-Foot Project, Maryland and Virginia
Fact Sheet
1 Feb 2015

Link

They're all about deepening the harbor for bigger and bigger ships, but not about protecting the bridge...

RE: Baltimore Bridge collapse after ship collision

Perhaps a Daytona style SAFER barrier would be more valuable than a few dolphins. Of course it would have to be on steroids as it's just a modern day bumper. [/jargon]

RE: Baltimore Bridge collapse after ship collision

I wonder if the engineers will consider the effects of climate change when designing the replacement bridge. The latest sea level rise map shows the harbor having serious water issues by 2050. And NOAA says their map may be a little low. Rebuilding the bridge will take a few years (the original took about 5 years). And most of the roadway to and from the bridge will have water issues before 2050. It doesn't make much sense to design a bridge to last a hundred years when you'll start having trouble getting to it only twenty years after it opens. The same thing applies to bridge protection structures which will become less effective as the water level rises.

RE: Baltimore Bridge collapse after ship collision

This is a joke, right?

RE: Baltimore Bridge collapse after ship collision

2
I don't think it is, they have already changed the codes this side of the pond to future proof against various predicted environment changes.

RE: Baltimore Bridge collapse after ship collision

I believe NOAA's latest assessment shows significant sea level change on the US's east coast by 2050. I doubt codes/regulations/standards will move fast enough to incorporate those changes, but it is coming.

RE: Baltimore Bridge collapse after ship collision

Get used to it Tug... it might be happening.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Baltimore Bridge collapse after ship collision

2


The FBI boarded MV Dali this morning, opening an investigation and preempting the NTSB and Coast Guard investigations, according the the Washington Post. The FBI is being tightlipped about what they are looking for but the Post imagines it to be about the crew setting sail knowing there were system problem aboard.
https://www.washingtonpost.com/dc-md-va/2024/04/15...

Roopinder Tara
Director of Content
ENGINEERING.com

RE: Baltimore Bridge collapse after ship collision

I bet that ladder seems 10X longer than it actually is when stepping off the little boat.

Why the FBI and not USCG?

RE: Baltimore Bridge collapse after ship collision

I'm trying to plot the precise path on CAD of the MV Dali in her last mile of so to show it be consistent with the path of a ship with a rudder locked in position, possibly a hard left. I can get approximates location from videos online but does anybody have the AIS data the videos were based on? Or know where I can get the data? AIS data has precise location and heading information that would be helpful in proving or disproving the rudder-locked-position theory.



Roopinder Tara
Director of Content
ENGINEERING.com

RE: Baltimore Bridge collapse after ship collision

I'd be careful about how you interpret the AIS data. It's good for giving other vessels a general overview of the traffic around them, which is its primary purpose; but is not designed or intended to be a high resolution and rapidly updating trace of a vessel's movements.

There are many factors which would have influenced the ship's heading after power loss. If the main engine was not powering ahead, the rudder would have quite limited influence on the ship's heading; and if it was powering astern while the ship was moving ahead, possibly no influence on the heading. The rudder is only properly effective when the ship is moving and powering ahead; it effectively redirects the ahead thrust of the propeller. The combination of current in the main channel, current from the side channel, and wind could explain the change in heading. The final stages of the turn could also, possibly, be the starboard bow grounding on the shallower water between the main channel and the bridge pier.

If they did go hard astern when the lights first came back on, that could account for the turn after that moment. This was my initial thought from the large cloud of dense black smoke and heading change, but I'm now more 50:50 on it.

Trying to resolve all of the above into a reliable analysis of the rudder position seems like a very tall order to me.

RE: Baltimore Bridge collapse after ship collision

My go to for ships is GCaptain and they haven't agreed on an answer.

RE: Baltimore Bridge collapse after ship collision

bridgebuster, thank you for saying that so I don't have to :)

The problem with sloppy work is that the supply FAR EXCEEDS the demand

RE: Baltimore Bridge collapse after ship collision

3
Gents,

Please reflect on your posts just above and consider deleting them as being off topic and turning a serious engineering thread into a political one.

Thank you.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Baltimore Bridge collapse after ship collision

Perfect time to make the Bmore Bridge Thread Part II.

RE: Baltimore Bridge collapse after ship collision

Quote (RoopinderTara)

I can get approximates location from videos online but does anybody have the AIS data the videos were based on?

I have looked for that data for a while now, with no success. But based on the various data plots, it looks like 3 points define the departure from a strait path and final contact with the bridge. Graphically, the first angle is about 5-6 degrees, and the final pair ~12 degrees, as if the ship had a constant force causing it's lateral displacement. I doubt the rudder was in play, as it needs the rush of water caused by the prop to be effective.

One source stated the ship's power was lost .6 naudical miles (.7 miles) from the bridge.

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

Recent Video Update, taken from the water: https://www.youtube.com/watch?v=Pt9lvf4FnZE

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

RE: Baltimore Bridge collapse after ship collision

Quote (RVAmeche (Mechanical))

I doubt codes/regulations/standards will move fast enough to incorporate those changes, but it is coming.

Only "code thing" that needs to change to address rising water levels is the FEMA Flood Map Program. Which is implemented by local ordinances. Most of what needs to change is the way flood occurrence elevations are calculated in areas subject to sea level rise.

A frequent requirement is that by ordnance the minimum build elevation is defined as the 100 year occurrence elevation + 1 foot. Amy thing below that elevation must be flood tolerant. This makes trouble for designing waterfront facilities (piers, etc).

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