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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

#631

Post by kapilvt »

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.

a Baltimore local harbor pilot was onboard from what I've read.

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

#632

Post by smrq »

Baxxter wrote: post #472
mikeyouse wrote: post #386

Earlier quoted context omitted.

Older bridges no, but newer bridges should absolutely. The Bay Bridge was struck in 2007 and came away mostly unscathed due to earlier efforts to prevent catastrophic damage in that scenario; https://en.m.wikipedia.org/wiki/Cosco_Busan_oil_spill Though the Maryland accident looks like it struck it dead on - just a massive amount of energy to absorb.

'The Bay Bridge' refers to something else in this part of the country. https://en.wikipedia.org/wiki/Chesapeake_Bay_Bridge

Hacker News:California::Internet:USA

It's assumed that everyone comes from California unless proven otherwise.

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

#633

Post by krisoft »

tomatotomato37 wrote: post #393
WarOnPrivacy wrote: post #344

Earlier quoted context omitted.

> the replacement bridge was built with a series of "structural dolphins" and concrete barriers to protect against ship strikes. Given how the Skyway collapse is burned into the local consciousness, I suspect some of the benefit comes from their visibility. I truly don't know how the dolphins would fair against a massive ship strike but I can imagine them doing their job. (ship passing): https://pbs.twimg.com/media/F…

I would also add those barriers seem to depend on the ship staying intact during collision. Given the immense inertia involved on the bigger ships I could just as easily see a scenario where the barrier ends up ripping through the lower hull while the rest of the ship continues forward.

> easily see a scenario where the barrier ends up ripping through the lower hull while the rest of the ship continues forward

I don’t think that is likely? My intuition is that in order to stay seaworthy ships are constructed with more integrity than that.

I don’t have any hard evidence though, just that I have looked at many ship collision/allision aftermath photos and what you describe is not a failure mode I have seen so far.

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

#634

Post by marpstar »

sickofparadox wrote: post #429
boringg wrote: post #397

This is a tragedy for those involved. My rough calculus points that the amount of force of this collision is on par with a large scale natural disaster. Everyone being surprised at the bridge collapsing needs to reconcile with the amount of force that struck the bridge - it is a truly significant amount of Newtons that hit the bridge. More than a train going from full speed to a full stop. Unbelievable amount of forc…

It's likely that a lot of people don't understand just how huge these ships are. I'd imagine that much of HN doesn't have a ton of firsthand experience with shipping yards or even close friends/relatives that work on these things. In my experience, almost nothing hides just how large it is than a giant ship.

My family and I drove through the Ports of LA/Long Beach on vacation last summer. A port is basically an entire city dedicated to getting things in/out of the water. Takes 15-20 minutes to drive through. You can't imagine the number of cranes/lifts. It's worth the drive through.

This ship was carrying ~5,000 TEU (Trailer Equivalent Units). Imagine 5,000 fully packed semi trucks crashing into the single upright of that bridge.

Even at 7.5 knots (~10mph) the bridge stood no chance.

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

#635

Post by OtherShrezzing »

hammock wrote: post #624
araes wrote: post #541

Earlier quoted context omitted.

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…

>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 hope, given the economic and humanitarian consequences of a crash, that we have simulators for this

We have miniature physical simulators for it with reduced scale ships & environments.

https://www.youtube.com/watch?v=jplrbxI5GN8

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

#636

Post by jcgrillo »

mcv wrote: post #622
jcgrillo wrote: post #594

Earlier quoted context omitted.

Blasting the horn repeatedly is not a standard signal, but there are standard signals which might apply to a situation like this, for example "vessel not under command", "collision imminent", "vessel reversing", etc.

Don't expect car drivers on the bridge to understand ship signals, though. Also, how does the driver know what to do? Stopping on the bridge, even well before the point where the ship hit, was clearly the wrong choice. Authorities need to stop new cars from entering the bridge while those on it leave, but that takes more than a handful of seconds to arrange. Unless there are traffic lights, perhaps.

Yes, there's no reason for a ship to attempt to signal drivers on a bridge, nor is there any way for them to do so. Signals are for communicating to other ships.

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

#637

Post by bsimpson »

dgfitz wrote: post #357

I heard on the local radio here, with one of the DJs being an ex-cop, his contact with EMS said the driver of the boat called a mayday and said to clear the bridge. Nope, can't prove it, but I imagine it'll come out in the news soon. So, not intentional.

Sounds like they were able to stop traffic in time, which is why they know the precise number of missing people.

They were construction workers fixing potholes.

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

#638

Post by Tokkemon »

koliber wrote: post #602

There was a video the other week on Reddit where a cargo ship devastated a few loading cranes in a port in Turkey. Now this. How often do cargo ships run into infrastructure? Is this just a coincidence that it happened twice in a few weeks?

Yes it's a coincidence.

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

#639

Post by Tokkemon »

0cf8612b2e1e wrote: post #618

Let’s say you had infinite money and no paperwork filings required. What is the fastest possible timeline in which a replacement bridge could be designed and completed? Just removing the detritus of the current bridge sounds like a multi month affair.

It probably won't take long to cut a hole in the wreckage to at least get one sea lane open so the port can still operate. A bunch of folks with metal cutting torches on a few dozen boats and a floating crane?

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

#640

Post by forgetfreeman »

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…

Catastrophic engine failure doesn't sound like a problem that's resolvable in 60 seconds.
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