Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Baltimore's Key Bridge struck by cargo ship, collapses

wbaltv.com

Post reply on HN
Print view View original

601–610 of 1001 posts

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

#601

Post by CydeWeys »

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

LOL, that figure is clearly off. That's double the population of the entire state!

Per another comment it's much closer to correct for the annual number of vehicle crossings.

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

#603

Post by pixl97 »

thekid314 wrote: post #597
paddy_m wrote: post #568

Earlier quoted context omitted.

On ships like this the propulsion is separate from the steering. There is a separate rudder that is close to, but not attached to the prop and propshaft. The propshaft is fixed. The rudder doesn't just "restart in a random position" it would remain in the previous position unless there was a physical piece that broke in the rudder gear. The fact that ship was able to reverse hard ( as evidenced by the slowdown), indi…

Was there a harbor pilot on board, or the normal ship pilot? Were there tug boats helping with the exit? I have often felt that the harbor protocols were overkill, but this is one of the times they could have helped.

Once the ship is under way I don't think the tugs hang around. They are just for the push away from the dock and initial turns.

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

#604

Post by kazinator »

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.

I think the only reasonable goal would be to design the bridge to minimize damage to it, so that one damaged section doesn't bring down others.

Building a bridge to actually stop the ship is not only infeasible, but it would likely kill (more) people onboard.

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

#605

Post by hrunt »

randerson wrote: post #595
jcranmer wrote: post #535

Earlier quoted context omitted.

The last car crossing that I can see clears the span about 1:28:06; the bridge collapses about 1:28:48. That's about 40 seconds of gap between the traffic and the collapse. I haven't timed how frequently cars are coming, but it seems to be about every 30 seconds or so, which--combined with the time it takes to cross the bridge--is evidence that a bridge closure was effected just before the bridge collapse.

Whoever was driving that last car had better go buy a lottery ticket right away.

Why? They already used up all their luck escaping the accident.

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

#606

Post by CydeWeys »

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…

One factor that a lot of people in this discussion are missing is that buildings are primarily built to resist vertical forces, because gravity is by far the largest force any building (or bridge) ever experiences.

Having a large force strike perpendicular to gravity is just not something it's designed for at all. All it ever has to handle in the form of force from that direction is wind, and that's absolutely nothing compared to a fully laden container ship hitting it.

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

#607

Post by dubcanada »

boringg wrote: post #588
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 much of this is falls on the protocols of the shipping company? I.e. the same shipping companies that gouged the planet during covid - did they strip away safety protocols in order for profits/expediency? Is this similar to Boeing for the shipping world? I realize it is early to come to any conclusions. The question of this being a rare one off vs container companies deprioritizing safety protocols is what I am i…

Boeing makes and sells planes, they don't fly people.

Maersk/ZIM rent container ships from another company who makes them and drive them around.

These are completely different companies. A more correct comparison would be something like Jetblue or American Airlines.

But I seriously doubt there is the result of some kind of profit hungry CEO. However I cannot with 100% say it's not until we find more details. But I feel confident enough to avoid the tin foil hat.

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

#608

Post by jcgrillo »

rightbyte wrote: post #575
jcgrillo wrote: post #555

Earlier quoted context omitted.

I'm not sure what configuration of props a ship like this has, but in my experience with a 40ft sailboat with a single propeller you have absolutely no rudder authority while reversing. I've read that some large ships also are direct drive--there's no transmission between the engine and the propeller, so "reversing" (if it's even possible) entails shutting down the engine and restarting it in reverse. This can be don…

> my experience with a 40ft sailboat with a single propeller you have absolutely no rudder authority while reversing. I have to protest here. Reversing and using the rudder on a 40ft boat works perfectly fine. I've done it on multiple sailing boats. You need to hold tight so that the rudder wont slap you if using a stick.

If you have enough way on to combat the prop walk, yes. But in a situation like backing down trying to come to a stop (at least in my boat, a 1962 Block Island 40) there's a very long "dead time" while transitioning from slowly moving forward to slowly moving in reverse where the rudder just doesn't do anything. The way I maneuver in these situations is to do all my heading corrections in forward gear, where prop wash over the rudder gives it authority. So it's a game of shots of reverse, corrections, rinse, repeat.

EDIT: also planning ahead is important, because if I do it right the prop walk in reverse can be used advantageously.

Also, with the BI-40's barn door rudder it'll slap you through the wheel if you're not careful. Almost broke my leg that way, not a lesson to forget.

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

#609

Post by verandaguy »

animex wrote: post #592
lotu wrote: post #587

Earlier quoted context omitted.

> 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? I would expect anyone piloting such a ship in a harbor/under bridges. We requite airline pilots to train for many unlikely plane failures because the alternative is letting planes crash that we could have saved with better training.

You can train for it, then how many years into your career you actually experience such a scenario are you likely to act instinctually and recover. The best solution would be to improve autopilot assist as it will never forget how to correct (if possible).

If it’s anything like airline pilot training, there’s periodic retraining and evaluation to make sure pilots have the right reactions in case of an emergency.
Post reply on HN