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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

#641

Post by major505 »

bastardoperator wrote: post #494
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…

The video is surreal, it looks like it barely bumps the bridge and 2 seconds later the entire thing is gone. I don't know what I was expecting, the bridge just looked extremely fragile, makes me wonder what other bridges are at risk of an event like this.

Bridges are design to withstand a very predictable type and direction of force. It can withstand the lateral wind, but imagine how much force a fully loaded cargo ship can put into it. Once one segment gone the rest is history, because makes the who construction imbalanced.

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

#642

Post by myself248 »

paddy_m wrote: post #554
myself248 wrote: post #488

Earlier quoted context omitted.

At least in small craft, bow thrusters are usually electric, with local batteries charged from the main engine room. I don't know what large craft are like, but it doesn't seem unreasonable that a bow thruster may remain operable even if the main engine fails. Clearly that's not required or they would've had it and used it, but it could be required if the regulations didn't suck. Furthermore, steering could absolutel…

The difference for a car and drive by wire system is that the failure mode of control systems on cars is normally catastrophic and dangerous. If a car loses steering or brakes, it will hit something within seconds 95% of the time. That ship spent 1 (4:30 to 5:30) hour of a presumably 10-20 day voyage in a critical control section. The tugs left the ship right around 5:08 (43 seconds into the video). A much better pol…

All valid points. Tugs are quite a reasonable option.

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

#643

Post by HaZeust »

boringg wrote: post #422
low_common wrote: post #402

Earlier quoted context omitted.

Your last sentence is pretentious and condescending.

To be fair I am truly surprised at the comment thread here and people being surprised that it collapsed and the lack of understanding of magnitude of forces. I always think of HN as a fairly educated group with a large portion of engineers (skewed heavily towards software which doesn't always have a background in the physical environment). I don't intend to sound pretentious or condescending. Maybe its more that I ne…

The absolute mass of container ships are inconceivable by default - it's really worth repeating how much weight and force they bear.

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

#644

Post by forgetfreeman »

animex wrote: post #592
lotu wrote: post #587

Earlier quoted context omitted.

> 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 expect anyone piloting such a ship in a harbor/under bridges. We requite airline pilots to train for many unlikely plane failures because the alternative is letting planes crash that we could have saved with better training.

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).

Nope. The military, aerospace, and medical industries have all refused full automation in life-or-death situations with cause.

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

#645

Post by aidos »

animex wrote: post #592
lotu wrote: post #587

Earlier quoted context omitted.

> 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 expect anyone piloting such a ship in a harbor/under bridges. We requite airline pilots to train for many unlikely plane failures because the alternative is letting planes crash that we could have saved with better training.

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).

I’ve done some sailing but have no real authority when it comes to vessels like these.

Friends of mine are pilots on the Thames (London) and I seem to recall one of them telling me it was over 10 years training before you could bring a big boat in. Pretty fascinating really - they figure out all the tides and weather and plan the route. On the day they board along with a sensor system that sits in the bridge and gives the position to a high level of accuracy.

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

#646

Post by bobthepanda »

kazinator wrote: post #604
hgfghj wrote: post #521

Earlier quoted context omitted.

That ship had a 10,000 TEU capacity and was actually hauling a little under 5,000 TEUs. An empty container weighs a little over 5,000lbs, and a full one can be up to 67,000lbs. If you do the math, you find that it’s just an astronomical amount of momentum, and there’s no effective defense for a bridge that needs support in more than 30 or so feet of water.

I think the only reasonable goal would be to design the bridge to minimize damage to it, so that one damaged section doesn't bring down others. Building a bridge to actually stop the ship is not only infeasible, but it would likely kill (more) people onboard.

the modern practice is layers of defense; in addition to building a bridge that doesn't fail at a single point of failure, you also generally design what's around a bridge pier to stop or at least slow down the ship (by, say, running aground onto a bed of rocks around a pier)

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

#647

Post by brewdad »

shagie wrote: post #516
Joker_vD wrote: post #473

Earlier quoted context omitted.

Where do you get those salary numbers from? The info about this "Dali" ship is not private: [0], and it lists the master's salary as $10,200 per month. [0] https://www.balticshipping.com/vessel/imo/9697428/seafarers

https://en.wikipedia.org/wiki/Maritime_pilot#Compensation > The Florida Alliance of Maritime Organizations reported that Florida pilots' annual salaries range from US$100,000 to US$400,000, on par with other US states that have large ports. Columbia Bar pilots earn approximately US$180,000 per year. A 2008 review of pilot salaries in the United States showed that pay ranged from about US$250,000 to over US$500,000 pe…

Columbia Bar pilots are grossly underpaid.

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

#648

Post by ProllyInfamous »

baxtr wrote: post #620
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…

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.

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

#649

Post by traceroute66 »

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…

> 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 think you are missing the point.

Clearly I am speculating, but I don't think any more experience would have helped in this event.

Why ? I think what happened today was almost entirely down to not being able to fight the basic Laws of Physics.

Its a well known fact that enormous ships take an equally enormous amount of time and distance to reflect the actions of the captain. You make an input and you see the result a bunch of time and distance later.

Time and distance were, sadly, not on the captain's side today. Physics took care of the rest.

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

#650

Post by squigz »

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?

What else do you think it might be?
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