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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

#701

Post by adrianmonk »

doer1984 wrote: post #688
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…

Ironically, simply bulking up the ground around the piers would have had the ship run aground; at 8 knots the ship would have slowed to a stop within several yards, and suffered minor damage, maybe would have required being tugged back into clear waters. Running aground puts the majority of impact into a downward force absorbed by the earth. It's hard to build a bridge pier that will withstand 200,000 tons of direct…

That's what makes sense to me. Ships are designed to minimize drag going through the water. But the friction of the entire hull scraping across the bottom should be MUCH larger and thus able to exert lots more stopping force.

Also, if the ground is sloped, it will act like a ramp, lifting the ship out of the water. The loss of buoyancy means its weight will push downward on the ground below it. An increased normal force means more friction, thus more stopping ability.

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

#702

Post by [deleted] »

archi42 wrote: post #305
Kye wrote: post #274

Earlier quoted context omitted.

Those are great for little boats like one of those superyachts. They become dominoes that hit before a boat like this: https://www.vesselfinder.com/?imo=9697428

Absolutely. 116851 long tons deadweight, which the Google info box says includes everything (busy now, so can't check in detail). That's 120,000,000 kg, so a little bit less than I guessed. Now looking at 10km/h or 6.2mi/h or 2.78m/s, that's enough to come up with a big E for E = 1/2 * m * v². The momentum p = m * v is also rather unpleasant. If the momentum was suddenly transferred into my 2,000 kg car (e.g. if the…

[deleted]

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

#703

Post by DiggyJohnson »

OJFord wrote: post #497
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…

Apparently (this is just via someone on Reddit who supposedly heard/read it somewhere) the ship mayday'd on losing power hoping the bridge could be cleared. But why not (or did it?) also just blast its horn repeatedly, drawing attention so people on or near the bridge would notice it and realise something was wrong and perhaps even where it was headed? I'm sure it's not allowed generally and not the protocol and what…

Because horn blasts are very specifically meant to communicate something to other ships. Once you're in "just blast it" mode you're seconds from disaster. I recognize the nobility of your suggestion, but I don't think it could have saved more than couple lives at most, probably none.

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

#704

Post by reliablereason »

hnburnsy wrote: post #487

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.

On the bridge of the ship one would imagine.

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

#705

Post by delichon »

CydeWeys wrote: post #598
thekid314 wrote: post #597

Earlier quoted context omitted.

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.

All pilots are "harbor pilots". Crew members who control the ship outside of port are just called crew members (captain, first mate, 2nd Officer, that kind of thing), never pilot.

There used to be! See William Adams, "the pilot of Miura" or "Miura Anjin", inspiration for John Blackthorne in James Clavell's Shogun.

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

#706

Post by jcranmer »

b33j0r wrote: post #208
Retric wrote: post #187

Earlier quoted context omitted.

Bridges only last for roughly 50 years. Considering such collisions are rare enough to make the news as a memorable event you can workout for yourself that the odds are quite low over a bridges lifespan. They are designed to withstand smaller boat impacts because they occur relatively frequently, but cost vs benefit on rare events that are difficult to mitigate is quite different.

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?

Depends on the "we" you're talking about, I guess.

In the DC/MD/VA area, almost all the bridges I can name are less than 100 years old. Woodrow Wilson, American Legion, Chesapeake Bay Bridge, Chesapeake Bay Bridge-Tunnel, Key Bridge, Key Bridge, Nice Bridge, Memorial Bridge, Chain Bridge, 14th street bridges... Some of those were even built after 2000! Also the New River Gorge Bridge in WV is pretty famous and not even 50.

Well, actually, the Key Bridge (in DC) apparently turned 100 years old last year. And I guess the Long Bridge (though not a road bridge) is also over 100...

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

#708

Post by londons_explore »

sierrah wrote: post #599
animex wrote: post #592

Earlier quoted context omitted.

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).

Lol you're right, controlling a ship with human inputs is so hard that is was the inspiration for a Russian shipmaster to create PID control

But I believe no big ships use any kind of autopilot while near shore. they only use it in the middle of the ocean.

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

#709

Post by hnburnsy »

hnburnsy wrote: post #487

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.

Looks like they were on the ship, should there also be a tug when piloting these ships?

https://www.dailymail.co.uk/news/article-13239953/Singaporea...

>The cargo ship that smashed into the Scott Key Bridge in Baltimore overnight was piloted by a specialized crew trained to avoid obstacles at ports, it has been revealed.

>The ship, a 948-foot-long DALI operated by Singaporean company Synergy Group, collided with the 1.2-mile bridge shortly after 1.26am as it left port.

>Maryland Transportation Secretary Paul Wiedefeld said on Tuesday morning it appears none of the 22 crewmembers were injured, as he revealed it was being steered by the specialist pilots.

>'Pilots move ships in and out of the Port of Baltimore,' he said at a press conference, noting that the specialist pilots depart the ships as soon as they are in open water.

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

#710

Post by EB-Barrington »

CIPHERSTONE wrote: post #658
paddy_m wrote: post #574

Earlier quoted context omitted.

To anyone reading this who isn't an experienced boater: If you are invited onto someone else's boat, sit down and shut up during docking, don't talk to friends, let the captain concentrate. Don't help, if the captain wants you to do something, they will let you know. If you think you know better than the captain, and this advice is unknown to you, you don't know better. Being a good guest during docking shows experie…

This is great advice. For myself, docking in windy situations can be nerve racking. The old adage is to only dock as fast as your willing to hit the pier, and for me this means slow as hell. I always let guests know exactly what I want them to do, and to your point, it's mainly to sit tight and let me focus.

Wind, current, tides, your own boat at risk as well as other people's boats alongside... docking can certainly get the heart pumping.

(Liveaboard cruiser here)

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