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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

#501

Post by danpalmer »

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.

It's somewhat counterintuitive how much energy can be in something moving so slowly. I say somewhat, because when you're up close it's much more obvious, but you're right that on a video it doesn't look like much.

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

#502

Post by dghlsakjg »

boringg wrote: post #367
irjustin wrote: post #96

Earlier quoted context omitted.

This situation is terrible, but to your specific question: Anyone can build a bridge, but it takes an engineer to barely make it stand.

Why are you throwing shade at civil structural engineering? Do all bridges we build need to be able to withstand the force of an entire shipping container bridge hitting it at high speed? What planet should an engineer think that a shipping container has managed to veer off course so badly that they hit a bridge at full speed, fully loaded? That is a sad and significant outlier event.

This is a common joke in engineering.

It’s not meant to be an insult, but a compliment noting that engineers know what the essential parts of the bridge are

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

#503

Post by [deleted] »

OJFord wrote: post #497
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…

Apparently (this is just via someone on Reddit who supposedly heard/read it somewhere) the ship mayday'd on losing power hoping the bridge could be cleared. But why not (or did it?) also just blast its horn repeatedly, drawing attention so people on or near the bridge would notice it and realise something was wrong and perhaps even where it was headed? I'm sure it's not allowed generally and not the protocol and what…

[deleted]

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

#504

Post by throwup238 »

bmitc wrote: post #500
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…

That timeline implies that there was only four minutes to respond. Is that correct? Where was the ship going? Does it travel under this bridge on its own power rather than a tug boat? What I am wondering is: why couldn't the bridge have been blocked off preventing casualties? It seems like more than just the boat and operators' failing if there's no time or secondary precautions if such failures occur. I wonder if it…

It was blocked off the shortly after the ship pilots sent their mayday signal and declared an emergency, giving the traffic that was on the bridge time to make it through.

Most (all?) of the people on the bridge were contractors repairing potholes.

> I wonder if it makes sense to protect bridges with pylons like they have in front of buildings to stop cars and trucks.

They're called "dolphins" and some bridges do have them.

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

#505

Post by ViewTrick1002 »

jordanb wrote: post #495
ianburrell wrote: post #482

Earlier quoted context omitted.

It wouldn't help with this accident, but you would think that the electronics would be on batteries. It wouldn't be too hard to have rack of batteries that would power the lights, instruments, radios, and sensors. Doesn't help if the propulsion or steering go out, but does make easier to know whats going on.

The problem is with steering. The rudder on a ship this big is going to be wall of steel several stories tall with gears as big as car. Warships have several independent backup steering options reducing finally to a worm gear at the top of the shaft with a winch handle big enough to put a gang of men on it. But ships like this will have none of that. They will have a small wheel or joystick on the bridge and if power…

Emergency steering gear is required on every commercial vessel and is regularly tested. We will have to wait for the investigation to see what actually happened.

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

#506

Post by themerone »

OJFord wrote: post #497
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…

Apparently (this is just via someone on Reddit who supposedly heard/read it somewhere) the ship mayday'd on losing power hoping the bridge could be cleared. But why not (or did it?) also just blast its horn repeatedly, drawing attention so people on or near the bridge would notice it and realise something was wrong and perhaps even where it was headed? I'm sure it's not allowed generally and not the protocol and what…

Why would a driver think a ship's horn was signaling them?

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

#507

Post by mlyle »

jordanb wrote: post #495
ianburrell wrote: post #482

Earlier quoted context omitted.

It wouldn't help with this accident, but you would think that the electronics would be on batteries. It wouldn't be too hard to have rack of batteries that would power the lights, instruments, radios, and sensors. Doesn't help if the propulsion or steering go out, but does make easier to know whats going on.

The problem is with steering. The rudder on a ship this big is going to be wall of steel several stories tall with gears as big as car. Warships have several independent backup steering options reducing finally to a worm gear at the top of the shaft with a winch handle big enough to put a gang of men on it. But ships like this will have none of that. They will have a small wheel or joystick on the bridge and if power…

> But really if we don't want accidents like this to happen the ship should have redundancy. A 10,000 TEU container ship is one of the largest and heaviest moving structures ever created by man. Why is it acceptable that it is driven by exactly one engine powering one screw in front of one rudder?

Perhaps because we have a whole lot of them going and a very low frequency of events like this.

Maybe there's some lighter weight interventions we could do that would further halve the risk of something like this happening that are less costly than fully redundant engine and drive.

They're supposed to have emergency steering gear. Why didn't it work? Maybe ships should have an auxiliary genset running while near land.

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

#508

Post by hangonhn »

danpalmer wrote: post #501
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.

It's somewhat counterintuitive how much energy can be in something moving so slowly. I say somewhat, because when you're up close it's much more obvious, but you're right that on a video it doesn't look like much.

The same go for cars. I was hit by a car which was already slowing down but over ran the line and hit me. The car couldn't have been going more than 10 mph but it was enough force to fracture my knee (the fracture type is also colloquially known as a bumper fracture).

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

#509

Post by divbzero »

ajdude wrote: post #481
jxdxbx wrote: post #136

Not that it matters to anyone else, but having driven across that bridge dozens of times with my kids, this is just shocking. It’s one of the main corridors in the area. Thank god it happened in the middle of the night, though that’ll be no consolation to the families of those who may have died.

I was incredibly worried about my dad, he's a truck driver and drove that bridge just an hour prior to this happening. I'm hearing there were at least 20 cars and a truck on the bridge, plus construction workers, at the time; my heart goes out to those families

Glad to hear your dad made it across safely.

According to current reports, the Maryland Transportation Authority Police responded to the ship’s “mayday” and stopped traffic in the minutes before the catastrophe, but 6 construction workers are still unaccounted for.

https://www.baltimoresun.com/2024/03/26/key-bridge-collapses...

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

#510

Post by jallen_dot_dev »

lenerdenator wrote: post #453
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…

How common are power outages on ships? I get that the captain might not have responded to it correctly but that seems like a thing that shouldn't happen, at least in my completely uneducated opinion.

Yeah that's not very typical, I'd like to make that point. These ships are built to very rigorous maritime engineering standards.
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