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Baltimore's Key Bridge struck by cargo ship, collapses

wbaltv.com

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

#431

Post by giantg2 »

QuarterReptile wrote: post #385
giantg2 wrote: post #359

A lot of these ships are controlled via GPS to keep them in the channels. I wonder if this crash will entail a software bug or system failure.

This ship was under pilotage at the time. In the same way that airline captains don't sleep during takeoff or landing, the captain is in the bridge (and with the assistance of a harbor-specific pilot) for the entirety of maneuvering in and out of a harbor.

Yeah, but they're usually relying on GPS, especially at night, even if they are at the controls. The controls are drive by wire anyways, even if they aren't using GPS plots.

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

#432

Post by Symmetry »

appplication wrote: post #420
gonzo41 wrote: post #120

Earlier quoted context omitted.

It appears to have lost power twice before veering into the foundation of the bridge..

How often would a large ship like the is lose power? Seems like terribly poor timing.

Problems are disproportionately likely to show up right as you start out on a journey.

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

#433

Post by SiempreViernes »

bmelton wrote: post #396
mannykannot wrote: post #283

Earlier quoted context omitted.

> But any preventive measure will have limits as what and how serious an impact it can deal with. The recent grounding of a large container ship in Baltimore's harbor channel demonstrates that a sufficiently massive berm will stop any ship. What's needed is the will to do something about low-probability but catastrophic events (though large-ship collisions, groundings and fortuitously harmless steering failures are f…

Starting from xoa's calculations above, assuming you can pack a berm with well-compacted soil enough that it can absorb 1,000 joules per cubic meter, you'd need a buffer of something like 10 meters surrounding each piling with 3 meters of depth to keep it safe from this kind of impact. That's 10 meters in every direction from the center of the support -- let's assume the support has a thickness of 0 meters for the sa…

You needn't stop the ship completely with the berm: just taking up enough energy that the bridge lives for 20 minutes after the impact would be useful.

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

#434

Post by appplication »

Symmetry wrote: post #432
appplication wrote: post #420

Earlier quoted context omitted.

How often would a large ship like the is lose power? Seems like terribly poor timing.

Problems are disproportionately likely to show up right as you start out on a journey.

I had assumed this was coming in, but starting out would make more sense.

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

#435

Post by foxhop »

TaylorAlexander wrote: post #66

Somehow I find it surprising how completely the bridge collapsed after the damage. I understand that a container ship collision is serious, but you could imagine a scenarios where the bridge slumps or buckles but doesn’t just disintegrate like that. It’s surprising that ships capable of doing this damage were probably regularly driving past it, and its safety as a thoroughfare depended entirely on those collisions no…

these ships have to be boarded by special port captians to make this maneuver.

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

#436

Post by throwanem »

mikeyouse wrote: post #414
throwanem wrote: post #363

Earlier quoted context omitted.

> Unlike the Philadelphia bridge span collapse recently, I don’t foresee this bridge being rebuilt anytime soon. How come?

In Philly, they sacrificed some of the road underneath it and narrowed the traffic lanes over the bridge to enable a very quick, albeit temporary repair. There’s no such option for a span of this length over a river — this is a decade long project that could potentially be sped up to be a years long one.

Sure, 5-10 years makes sense especially considering it took 5 years to build last time. But GP's formulation seemed to suggest a considerably longer expectation, and that's more what I was wondering about.

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

#437

Post by dgfitz »

desro wrote: post #421
dgfitz wrote: post #267

Earlier quoted context omitted.

I think 30-35k cars a day cross that bridge. Being local to the area, is is going to make traffic in the entire metro area much worse, and it is already awful.

Report from CBS News mentions the bridge handled "11.5 million" vehicles a day. EDIT: That number seemed fishy; I think the reporter is referring to the traffic along the entire I-95 corridor. https://x.com/CBSNews/status/1772556368106450953?s=20

It is between 30-35k/day, about 12.5 million/yr.

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

#438

Post by paddy_m »

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 channel, more of a translation)

By 1:26.45 the ship has obviously turned in the channel pointing at the pier. Full reverse would cause prop walk to change heading angle;

1:28.52 impact at 7.6 Knots. Camera says 1:28.52, AIS reports the ship still moving at 1:29:35

https://www.youtube.com/watch?v=N39w6aQFKSQ

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

#439

Post by dhc02 »

hgomersall wrote: post #260

I was wondering after watching the video whether there could be an emergency bridge closure protocol if a ship veers off its intended course. It naively looks to me like there would be sufficient time to log the course deviation and stop vehicles from entering the bridge with lights and sirens and stuff.

It seems pretty clear from the video that something like this actually happened. The only vehicles left on the bridge at the time of impact were stationary emergency services vehicles with flashing lights. So it would appear they knew it was imminent and cleared the bridge (although they underestimated the extent of the damage the impact would cause).

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

#440

Post by yifanl »

hgomersall wrote: post #260

I was wondering after watching the video whether there could be an emergency bridge closure protocol if a ship veers off its intended course. It naively looks to me like there would be sufficient time to log the course deviation and stop vehicles from entering the bridge with lights and sirens and stuff.

According to AP, the ship was able to issue a mayday and passengers of the bridge were warned: https://apnews.com/article/baltimore-bridge-collapse-53169b3...

> The operators of the ship issued a mayday call moments before the crash that took down the Francis Scott Key Bridge, enabling authorities to limit vehicle traffic on the span, Maryland’s governor said.

I don't know how long "moments" was, but presumably about as much warning as any automated system could provide.

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