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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

#801

Post by twic »

reactordev wrote: post #749
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…

At this point in the journey, they were cleared of the docks but not the channel. There wouldn't be a docking pilot on board nor would there be any tugs. It was cleared and under it's own propulsion until it wasn't. My sailors guess from the footage and the reports is diesel generator failure(s) resulting in loss of power, restoration of power, then loss of power again. Bypassing the diesel generator (which provides…

The ship's managers (which I believe means the company which chartered it from its owners, and were operating it) say there were two pilots on board:

https://www.synergymarinegroup.com/dali-imo-9697428/

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

#802

Post by zrm »

mlyle wrote: post #507
jordanb wrote: post #495

Earlier quoted context omitted.

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 lighte…

> 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.

Redundancy doesn't inherently have to cost a lot more. For example, if you have three engines driving three props, they can each be 1/3 as large, and not necessarily weigh much more if at all. But then if you lose one, you lose 1/3 power rather than experiencing total loss of control.

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

#803

Post by antisthenes »

jihadjihad wrote: post #384
dwightgunning wrote: post #28

I had a hunch this was the bridge featured in The Wire s2e1, "Ebb Tide". Classic McNulty; a great season opener. https://en.wikipedia.org/wiki/Ebb_Tide_(The_Wire)

Season 2 of The Wire is the single greatest work of television I've ever seen. It's as rich as a novel, as tragic as something out of Shakespeare. Seriously. If anyone hasn't seen The Wire, do yourself a favor and give it a watch.

The great thing about Season 2 of The Wire is that it works well both as a standalone mini-series and as a segue from Season 1 to Season 3.

Aside from great acting and direction, of course.

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

#804

Post by commentenjoyer »

Solvency wrote: post #797
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…

> I am also a bit surprised at how many people don't grasp this or grasp engineering, magnitude of forces and design principles. Who are you even referring to? Are you just inventing a population of people in your mind to flex against here? Trust me, people get it.

[flagged]

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

#805

Post by jasondigitized »

xp84 wrote: post #753
1letterunixname wrote: post #722

Earlier quoted context omitted.

I hope the next POTUS makes good on Biden's promises because Baltimore and Maryland will need federal assistance since they can't afford such a burden. And I assume there will lawsuits to recover costs as this caused economic damage and risk to life (8 people unaccounted for at current time).

I'm kind of confused how a President can promise something like that. He doesn't have any power to appropriate money, and given his party's lack of control of Congress, I'd argue he can't promise anything. Not to mention that one can scarcely find a "bluer" area than Baltimore -- I would assume that the most proudly right-wing politicians would be more than happy to let Baltimore suffer to score points with their pol…

Industry has the power here.

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

#806

Post by darkclouds »

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…

[dead]

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

#807

Post by pgwhalen »

Solvency wrote: post #797
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…

> I am also a bit surprised at how many people don't grasp this or grasp engineering, magnitude of forces and design principles. Who are you even referring to? Are you just inventing a population of people in your mind to flex against here? Trust me, people get it.

Seems a bit gauche to link to them, but there are comments all over this thread, including top level ones.

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

#808

Post by [deleted] »

mschuster91 wrote: post #764
epcoa wrote: post #617

Earlier quoted context omitted.

> event far better than the local news. That’s such a ludicrously low bar that I’m not even sure this would qualify as a compliment to these alternative producers.

One might expect that local news are well connected with those who actually did construction, planning and whatnot of such projects, or emergency responders, or disaster mitigation, or people specialized in local geology / hydrology to show up challenges... The sad truth is that "local" news more often than not barely has any local people any more, a lot of content is directly ripped off from others (especially fire…

[deleted]

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

#809

Post by Arrath »

efitz wrote: post #786
Arrath wrote: post #739

Earlier quoted context omitted.

It seems much more reasonable to only disengage the tugboats that were already helping the container ship get under way once it clears navigation hazards like the bridge, instead of keeping 24/7 quick-response tugboats at the bridge that try to intercept an out of control ship in a bare few minutes.

Moving large boats across water is slow. The Francis Scott Key bridge was 8600 feet long, or 1.4 nautical miles. AFAICT there were just over 4 minutes from the time that the first power outage started until the ship struck the piling. A modern harbor tugboat can go perhaps 15 knots. In 4 minutes this means it would travel 4 nautical miles, at the very best (running start in correct direction). So let's say that there…

Thank you for putting it into numbers!

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

#810

Post by colomon »

maxerickson wrote: post #253
b33j0r wrote: post #208

Earlier quoted context omitted.

Interested in this claim, because it sounds about right, except that I can’t name a bridge constructed in the past 50 years. The bridges we can all name are pushing 100+ right?

Mackinac Bridge is somewhat famous, built in the 1950s. They more or less do continuous maintenance during the warmer months of the year. (So older than 50, but younger than 100)

First span of the Blue Water Bridge (Port Huron to Sarnia) built 1938, doing just fine as far as I know. (Drove over it a couple of weekends ago.) Second span was 1997.
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