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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

#881

Post by wyldfire »

paddy_m wrote: post #445
secstate wrote: post #442

Earlier quoted context omitted.

Does that mean this was effectively captain error? Like in response to a power outage the decision was made to try to reverse and rather than arrest forward momentum it just pushed their forward vector into the piling?

I would tend to think so. The pilot should have anticipated prop walk and known that the ship had no chance of stopping before the bridge. I’m trying to find a color coded current map. Wind too. I wouldn’t expect wind or current to cause the pronounced heading change that is visible. The drift seems possible. Note: I’m an experienced dinghy/keelboat sailor, but lack virtually any experience driving boats under power,…

For some reason, I thought that large vessels hired a local pilot to navigate their way through places like this.

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

#883

Post by jasonwatkinspdx »

nytesky wrote: post #416
ToucanLoucan wrote: post #347

Earlier quoted context omitted.

I've seen close-up video where you can see the ship losing electrical power twice for not-insubstantial times as it approaches the column. I suspect that was a much larger factor in the collision than anything the crew may or may not have done. Warning time doesn't mean shit if you can't steer.

https://twitter.com/ChaudharyParvez/status/17725385394958090... Posted video of power loss. Also black smoke coming out rear — is that normal? Any clue of what onboard crisis they were dealing with?

The black smoke is most likely them running the engine in full reverse in an attempt to avoid the collision.

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

#884

Post by robk »

keepamovin wrote: post #878

Francis Scott Key wrote the Star-Spangled Banner, which later became the US national anthem, while gazing across this same Patapsco river in the morning after a battle and saw that the flag was "still there". On the morning of March 26, 2024, the Bridge in his name was no longer there. Sad. The bridge stood for 47 years and 3 days (17170 days) before destroyed by a trade ship from Asia headed for Indian waters. The t…

LLM for Poetic writing?

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

#885

Post by jasonwatkinspdx »

Domenic_S wrote: post #451
nytesky wrote: post #416

Earlier quoted context omitted.

https://twitter.com/ChaudharyParvez/status/17725385394958090... Posted video of power loss. Also black smoke coming out rear — is that normal? Any clue of what onboard crisis they were dealing with?

seems like they should have turned left and tried to go under the middle section there instead of cranking all the way around right. I imagine they were under task saturation with the power outages though.

I think we should restrain ourselves from armchair judgements when basically no one here is a harbor pilot, let alone someone informed with what was happening in the moment in this event.

What happened will be meticulously reconstructed and everyone involved in this is going to have their lives put under a microscope for years worth of legal battles. I don't think we should rush to judgement or second guess from a position of ignorance.

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

#886

Post by fsckboy »

paddy_m wrote: post #568
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…

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…

on a large vessel, I thought that the captain does not steer the vessel, just gives commands to the helmsman, and same with the pilot. So, in a certain sense, they don't have the direct skills that the helmsman does. And speed/power/direction are indirect through the engine room; it's not a like a little motorboat, all controlled in one place by one guy.

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

#887

Post by ClassyJacket »

ericyd wrote: post #339
IG_Semmelweiss wrote: post #206

This port has a very large volume of car shipping. The ro-ro shipping costs are expected to go much higher as a result of this accident. If you were in the market for a car in the US east coast , act now before prices go up!

A bunch of people die and this is your response?

People die all the time dude.

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

#888

Post by btbuildem »

KoftaBob wrote: post #583
btbuildem wrote: post #338

Earlier quoted context omitted.

If you think about this for a minute, you'll realize that what you're asking for is pretty much impossible. What would these artificial islands be made of? Sand, gravel, concrete rubble? This is a river, the constant current of the water erodes anything that resists it by staying in place. Piling up enough material to resist erosion and create a meaningful obstacle to 70000 tonnes in motion, that would significantly…

There are real world examples of what it would look like, they're called "dolphins": https://en.wikipedia.org/wiki/Dolphin_(structure)#/media/Fil... "The new bridge is protected by 36 dolphins: four large dolphins protecting the two main pylons supporting the cable-stayed main span plus 32 smaller dolphins protecting bridge piers for 1⁄4 mi (1⁄2 km) to either side of the main span"

Dolphins seem to be just pilings tied together.. how could those withstand the impact of a loaded container ship?

For something a bit more sturdy, look at the main pylons of the Jacques Cartier bridge in Montreal [1] - these are meant to withstand annual ice rush, hundreds of tons of ice floe moving with the current of the river.

Interestingly, while the Saint Lawrence is a very active shipping channel, most shipping near the city moves through the seaway canal [2], which has solid earthen berms reinforced with concrete wherever it crosses a bridge span [3], [4] making it next to impossible for this type of accident to occur.

If memory serves right, the seaway was built to avoid the strong currents and wild rapids of the river; there are a set of locks [5] upriver, and the engineering around bridge crossings [6] seems consistent as you trace its path

1: https://www.google.com/maps/@45.5198582,-73.5385996,94a,35y,...

2: https://www.google.com/maps/@45.5237446,-73.5262812,90a,35y,...

3: https://www.google.com/maps/@45.4986758,-73.5188312,123a,35y...

4: https://www.google.com/maps/@45.4717554,-73.5051917,148a,35y...

5: https://www.google.com/maps/@45.4080264,-73.5557603,298a,35y...

6: https://www.google.com/maps/@45.4082771,-73.6528304,266a,35y...

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

#889

Post by AnarchismIsCool »

naasking wrote: post #839
anigbrowl wrote: post #527

Earlier quoted context omitted.

It's not the impact, it's the fact that it just keeps pushing. Movies commonly use slow motion and time extension via editing for destruction scenes because (as we've just seen) real time doesn't always look impressive to the untrained eye. Also, there's a lot of mass concentrated in that ship. It's the equivalent of hitting a window with a sledgehammer. Small recreational vessels could probably crash into those pylo…

Indeed, the whole bridge failed because the impact didn't exceed the impact strength of the bridge's material, which means the whole bridge bent until the deflection exceeded the tensile strength of the material. A missile impact with the same total energy would exceed impact strength and would probably have destroyed only part of the bridge.

Did the math, this seems surprisingly spot on, at least from the energy perspective. 100k tons going 7.5 kts is about 160kg tnt equivalent which is a little less than the explosive power of a Mk83/GBU-32, probably not enough to take down an entire bridge, just one span if you're lucky. That said, the issue is the bomb expends most of its energy moving air around, the freighter expended nearly 100% of its energy on the bridge.

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

#890

Post by soderfoo »

robotnikman wrote: post #486

>a Mass Casualty Incident has been Declared with over a Dozen Cars and many Individuals said to be in the Water. This is literally like out of a nightmare I sometimes have, falling off of a bridge in my car into the water...

Ughh. This triggered the anxiety I feel when stuck in traffic on a tall bridge, like the Verrazzano bridge in NYC.
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