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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

#732

The Association of Maryland (boat) Pilots literally has a header image of a harbor pilot tug escorting a cargo ship to the Key Bridge... https://www.mdpilots.com/ Wonder where they were.

Here is real time playback of the incident, you can see both tugs leave the ship and do not accompany it past the bridge. You can see one of the tugs turn and head back to the ship before the collision...

https://twitter.com/MarineTraffic/status/1772545501612671284

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

#733
post #43

Earlier quoted context omitted.

I would want to first investigate how it happened and take care of the victims and their families. Then I would start planning the shiny new thing.

You're not qualified to run for president if you can't fart and chew gum at the same time. https://www.independent.co.uk/news/presidents/gerald-r-ford-... >Lyndon B Johnson is often reported to have said of Ford that “He can’t walk and chew gum at the same time.” What he did say was “He can’t fart and chew gum at the same time.” The US media deliberately misrepresented the remark in the interests of decency. https://…

I'm reminded of the press howling about how President Clinton needed to resign because his legal issues cough blow job cough prevented him devoting full attention to the presidency. Which was amusing since anyone paying attention could see it wasn't slowing him down at all.

He went on to clobber Dole in the 96 election.

Story about LBJ, one time a society matron buttonholed Lady Bird and told her that she needed to get LBJ to stop saying manure so much. Lady Bird said I will not because you have no idea how hard it was to get him to say manure.

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

#736
post #296

Earlier quoted context omitted.

At least in the links with the video now you can see that the container ship directly hits one of the two main (and in the central area only) pillars completely collapsing it. No matter(1) the engineering there is no pretty much way to not lose the whole large middle area and left area leading to the destroyed pillar in that situation. Such a collapse crates so much force (tension vibrations etc.) so that the collaps…

Just to put some numbers on this: The MV Dali (IMO#9697428) is a little over 95000 GT, or ballpark-ish probably around 114000 tons loaded (and it seems to have been loaded, which would make sense on departure). If it was going even 5kn (2.6 m/s) that'd be about 300 million newton-seconds, or about 3.3 times the momentum of a large jumbo jet like a 747 shortly at cruising speed (around 560 mph). It'd still have the sa…

Your math appears off by an order of magnitude. KE = ½mv^2. [J]

Ship KE = 0.5 * (114000 short tons) * (7.5 knots)^2 = ~7.7e8 J.

747 KE = 0.5 * (510,000 lbs) * (560 mph)^2 = ~7.25e9 J.

747 avg weight = (MTOW + OEW) / 2 = ~510,000 lbs

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

#737

Earlier quoted context omitted.

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 was…

Nice boat! Ye it does not look too nimble in harbours. Somewhere over 40ft with "light" boats is where I feel you get into the "you got one chance" harbour manouvers (unless there is some front sideways motor cheating). It happens something that I really can't explain, but I guess it is weight related. Or maybe area. Dunno.

Yeah it's right around 20000lb displacement, so momentum is a real thing ;). The fiberglass is over 2" thick at the keel tapering to a mere 1" at the hull to deck joint. Decks are solid glass as well. At the time it was a newfangled material and they were scared of it so they used a lot.

Also, the bow seems to catch the wind really hard so you can get spun around if it's blowing and you head off the wind too much without enough way on. Leave room, plan ahead, have a backup plan, etc.

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

#738

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…

I don’t drive boats or around water much but I’ve seen “bumpers” on bridge pylons before that make a collision more of a glancing blow and guide the boat to the side. I guess there wasn’t any installed on this bridge? Also, someone on Imgur pointed out that when this bridge was built boats that large weren’t a risk. That may or may not be true but sounds plausible.

Fenders and such. A major problem is this bridge was designed and built in an era where ships were substantially smaller (3000 TEU) than they are today (20000 TEU).

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

#739
post #620

Earlier quoted context omitted.

Can anyone say if there is the slightest possibility that this was caused by an Cyber attack?

As an inland armchair-captain, I want to admonish that tugboats should probably always be stationed around bridges to intercept such off-course mariners.

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.

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

#740
post #353

Earlier quoted context omitted.

I don’t drive boats or around water much but I’ve seen “bumpers” on bridge pylons before that make a collision more of a glancing blow and guide the boat to the side. I guess there wasn’t any installed on this bridge? Also, someone on Imgur pointed out that when this bridge was built boats that large weren’t a risk. That may or may not be true but sounds plausible.

> when this bridge was built boats that large weren’t a risk Doesn't sound plausible to me. Very large Panamax ships were used in the 1970's when the bridge was built.

Sorry, but you're very wrong. A civil engineer on Sky News even raised this issue.

https://www.container-transportation.com/worlds-largest-cont...

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