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Baltimore's Key Bridge struck by cargo ship, collapses

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Re: Baltimore's Key Bridge struck by cargo ship, collapses

#541

Post by araes »

paddy_m wrote: post #438

Youtube tracking analysis from a knowledgeable mariner. He says that at about 1:24 AM the ship loses power (from video feed) while traveling 8.5 knots. at 1:25.30 power is restored. at 12:25.59 the ship shows smoke. The ship has already drifted in the channel. It is believed that at this time the ship applied full reverse power as evidenced by the black smoke. (My analysis: the ship drifted but hasn't turned in the c…

Current personal suspicion after watching your linked video (excellent discussion by the wgowshipping author) is:

Catastrophic engine failure (1:24) causing wide scale power loss.

No rudder control, rudder drift, and ship alignment drift (1:24-1:25:30)

Power restored and ship reengages prop with bad ship/ruddder alignment (1:25). However, ship is now pushing itself into a further bad turn. Pilot likely stomps the brakes realizing misalignment. Obviously 2-3 minutes is not enough to stop 100,000 tons at 8.5 kts, since it only got to 7.5 kts before crashing. Power loss may have caused total rudder loss.

Similar to a car that hits ice, wheels have arbitrary alignment when they reengage road, when power starts being delivered again, car swerves towards concrete barrier even with brakes. Driver with limited crash experience is mostly just panicking and stomping.

How many pilots, trained or not, really have any experience with a 100,000 ton ship in a crash situation with responses where seconds matter?

Edit: Also, economic disaster for Baltimore.

> (Wiki) The Port of Baltimore generates $3 billion in annual wages and salary, as well as supporting 14,630 direct jobs and 108,000 jobs connected to port work. In 2014, the port generated more than $300 million in taxes. 1st in automobiles, light trucks, farm and construction machinery, imported forest products, aluminum, and sugar. 2nd in coal exports.

Edit2: Bloomberg has an economic look including info on autos. ~$500 million in March 2024 so far. Honda, Mercedes, Subaru likely worst hit. https://pbs.twimg.com/media/GJmvXiCWkAAgDcE?format=png&name=...

3,600 commercial trucks / day. Hazardous material transport has a 30 mile detour. Baltimore had $350 million of insurance. However, Brent Spence Bridge is noted for cost comparison at $3.6 billion and 1/5 the length.

Baltimore StreamTime also has live view with ongoing discussion. https://www.youtube.com/watch?v=83a7h3kkgPg

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#542

Post by samstave »

hgfghj wrote: post #521
bastardoperator wrote: post #494

Earlier quoted context omitted.

The video is surreal, it looks like it barely bumps the bridge and 2 seconds later the entire thing is gone. I don't know what I was expecting, the bridge just looked extremely fragile, makes me wonder what other bridges are at risk of an event like this.

That ship had a 10,000 TEU capacity and was actually hauling a little under 5,000 TEUs. An empty container weighs a little over 5,000lbs, and a full one can be up to 67,000lbs. If you do the math, you find that it’s just an astronomical amount of momentum, and there’s no effective defense for a bridge that needs support in more than 30 or so feet of water.

Thank FN gosh that those TEUs were likely ~mostly empty returns.

If thems be full, that guy would be illegally parked for far longer.

--

What is the traffick-routing-around plan look like? (both sea and land, helicopters cry in lack of TEU)

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#543

Post by 16bytes »

G0dchi1d wrote: post #388

Every bridge with large cargo ship traffic beneath them should have channels designed to guide the commercial traffic, installed beneath them. Every city with bridges like these should, with state AND federal funding, should begin the process of constructing such "guidance channels" beneath these bridges IMMEDIATELY!!! It should be IMPOSSIBLE for Ships large enough to damage bridges to even be able to come into conta…

What you are proposing isn't feasible from an engineering perspective. This isn't like putting a guard rail up.

To make damage from collisions "impossible" you'd have to build embankments up so high that the bridge would effectively be sitting on solid ground the entire way across and no ships could pass anywhere.

Sure, there are ways to mitigate collisions and the new bridge they build will no doubt be more resilient, but it's not realistic to completely eliminate such risk.

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#544

Post by mannykannot »

Retric wrote: post #187
HlessClaudesman wrote: post #170

Earlier quoted context omitted.

On a long enough timeline we all get rammed by a container ship. I would be interested to know some calculations with factors like: expected bridge lifetime, chance of being rammed per year, cost of making supports strong enough plus an extra safety margin to survive maximum ramming force, cost of having major commercial shipping route unusable for an extended period.

Bridges only last for roughly 50 years. Considering such collisions are rare enough to make the news as a memorable event you can workout for yourself that the odds are quite low over a bridges lifespan. They are designed to withstand smaller boat impacts because they occur relatively frequently, but cost vs benefit on rare events that are difficult to mitigate is quite different.

An obsolete or worn-out bridge is likely to be replaced by another, and in such cases, a risk analysis which potentially comes to different conclusions depending on how often such a replacement occurs is missing the point.

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#545

Post by toss1 »

Diederich wrote: post #452
toss1 wrote: post #398

Earlier quoted context omitted.

>>Because the Port of Baltimore is a very major port, and not allowing ships under it really isn't an option. It is now a very large port that is completely closed off from the sea. And two sides of the city no longer linked The damage from this accident is only beginning. Even if loss of control of a large container ship was considered in the design of the city, port, and that particular bridge, ships were not even…

> And, it lost power at almost exactly the worst moment. What are the odds? I don't know, but I suspect we don't hear much about all the times power is lost at moments that are less than the worst.

EXACTLY!! If it happens often, and they just restart because it's no big deal in the ocean, we wouldn't hear about it.

Of course, it seems that a high(er) frequency of failures should be taken into account for zones where it is critical, such as in port. I just saw a few days ago that a ship docking took out a couple of cargo cranes (sadly, badly injuring a crane operator); didn't seem like a power outage, more of a misjudged steering.

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#546

Post by CalChris »

TylerE wrote: post #478
Joker_vD wrote: post #473

Earlier quoted context omitted.

Where do you get those salary numbers from? The info about this "Dali" ship is not private: [0], and it lists the master's salary as $10,200 per month. [0] https://www.balticshipping.com/vessel/imo/9697428/seafarers

The pilot is employed by the port/government, not the ship. They drive to just outside the entrance, then they get off onto a tugboat or some other small utility vessel.

Harbor pilots are licensed by the state (Maryland) require a degree from one of the maritime colleges, deck license, …, are represented by a pilots union (Association of Maryland Pilots) but are employed independently.

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#547

Post by pseingatl »

araes wrote: post #541
paddy_m wrote: post #438

Youtube tracking analysis from a knowledgeable mariner. He says that at about 1:24 AM the ship loses power (from video feed) while traveling 8.5 knots. at 1:25.30 power is restored. at 12:25.59 the ship shows smoke. The ship has already drifted in the channel. It is believed that at this time the ship applied full reverse power as evidenced by the black smoke. (My analysis: the ship drifted but hasn't turned in the c…

Current personal suspicion after watching your linked video (excellent discussion by the wgowshipping author) is: Catastrophic engine failure (1:24) causing wide scale power loss. No rudder control, rudder drift, and ship alignment drift (1:24-1:25:30) Power restored and ship reengages prop with bad ship/ruddder alignment (1:25). However, ship is now pushing itself into a further bad turn. Pilot likely stomps the bra…

Panama Canal pilots.

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#549

Post by HarryHirsch »

hgfghj wrote: post #521
bastardoperator wrote: post #494

Earlier quoted context omitted.

The video is surreal, it looks like it barely bumps the bridge and 2 seconds later the entire thing is gone. I don't know what I was expecting, the bridge just looked extremely fragile, makes me wonder what other bridges are at risk of an event like this.

That ship had a 10,000 TEU capacity and was actually hauling a little under 5,000 TEUs. An empty container weighs a little over 5,000lbs, and a full one can be up to 67,000lbs. If you do the math, you find that it’s just an astronomical amount of momentum, and there’s no effective defense for a bridge that needs support in more than 30 or so feet of water.

there’s no effective defense for a bridge that needs support in more than 30 or so feet of water

You put in sheet piling 50 meters upstream, and you fill the box with rocks. That's state of the art practice, nowadays, but that bridge was 50 years old.

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#550

Post by throw0101b »

bastardoperator wrote: post #494
paddy_m wrote: post #438

Youtube tracking analysis from a knowledgeable mariner. He says that at about 1:24 AM the ship loses power (from video feed) while traveling 8.5 knots. at 1:25.30 power is restored. at 12:25.59 the ship shows smoke. The ship has already drifted in the channel. It is believed that at this time the ship applied full reverse power as evidenced by the black smoke. (My analysis: the ship drifted but hasn't turned in the c…

The video is surreal, it looks like it barely bumps the bridge and 2 seconds later the entire thing is gone. I don't know what I was expecting, the bridge just looked extremely fragile, makes me wonder what other bridges are at risk of an event like this.

> I don't know what I was expecting, the bridge just looked extremely fragile, makes me wonder what other bridges are at risk of an event like this.

The bridge style in question

> Conversely, continuous truss bridges rely on rigid truss connections throughout the structure for stability. Severing a continuous truss mid-span endangers the structure. However, continuous truss bridges do not experience the tipping forces that a cantilever bridge must resist because the main span of a continuous truss bridge is supported at both ends.

* https://en.wikipedia.org/wiki/Continuous_truss_bridge

* https://en.wikipedia.org/wiki/Francis_Scott_Key_Bridge_(Balt...

So taking out one end basically takes out the whole thing.

I would not be surprised that when they build the replacement, it will be a design where the individual components are more self-resilient, like:

* https://en.wikipedia.org/wiki/Cable-stayed_bridge

The engineering best practices, budgets, and needs may have been different fifty years ago. Cargo ships were also a lot smaller fifty years ago.

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