871–880 of 1001 posts
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> It's somewhat counterintuitive how much energy can be in something moving so slowly. Reminder: Kinetic Energy = ½mv^2 Squaring numbers can make them big in a hurry.
But in this case with slow speed, it's the massive (literally) amount of mass of the cargo ship that gives it an un-intuitively large amount of energy.
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> 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…
> One might expect that local news
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It was a massive boat. They don't change direction very easily.
Well engineered small things can redirect a moving thing several orders of magnitude more massive. Consider guardrails on the side of a road; those guard rails might be less than 100 Kg but together they're rated to redirect the force of a car weighing thousands of Kg traveling at tens of K/h. That's a lot of force to redirect for such a small and cheap barrier; imaging what a more expensive and larger barrier can do…
I also don't think the weight of the guardrail is what matters. Its strength is derived from the strength of the materials and being anchored in the earth.
In any case, any vehicle driving directly into a guardrail is going to plow right through.
I just don't think this guardrail thing is a great analogy.
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The last car crossing that I can see clears the span about 1:28:06; the bridge collapses about 1:28:48. That's about 40 seconds of gap between the traffic and the collapse. I haven't timed how frequently cars are coming, but it seems to be about every 30 seconds or so, which--combined with the time it takes to cross the bridge--is evidence that a bridge closure was effected just before the bridge collapse.
Whoever was driving that last car had better go buy a lottery ticket right away.
https://youtube.com/watch?v=jplrbxI5GN8&pp=ygUYc2hpcCB0cmFpb...
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How about instead of adding "bumpers," it becomes required for a tug boat to help guide past infrastructure spans like bridges, rail, gas.
There is already something like this in use: harbor pilots, who have specialized knowledge of specific ports and board vessels to navigate them through critical transit zones. It is reported that there were pilots on board navigating at the time of the collision. Tugs are used in tight locations, but they can only change a ship's speed at a very slow rate compared to that ship's engines. By analogy, you can pull a tr…
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Local to the area. This was devastating news to wake up to. I don't know what's wrong with me but seeing this and knowing there were casualties made me cry. Edit: Maybe I'm just tired and need more sleep.
Do you happen to know how they stopped traffic? Are there warning lights at the ends of the bridge? I have seen bridges of this sort but they are fairly rare. I'm wondering if that's how they stopped almost all of the traffic. Flip a switch, most people stop, a couple of assholes blow through the caution and FAFO.
The bridge stood for 47 years and 3 days (17170 days) before destroyed by a trade ship from Asia headed for Indian waters. The tragedy occured when the engine of the tradeship failed resulting in it being adrift until colliding with the bridge.
The Key bridge collapsed 209 years after its namesake wrote the Star-Spangled Banner. The embarrassed tradeship had been christened Dali: a name famous from the Spanish surrealist painter known for depicting melting clocks, not bridges.
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…
This
> Similar to a car that hits ice, wheels have arbitrary alignment when they reengage road, when power starts being delivered again, car swerves towards concrete barrier even with brakes. Driver with limited crash experience is mostly just panicking and stomping.
is almost certainly not the case on a large ship. The rudder is rotated hydraulically. Loss of power simply causes the rudder to stop moving, it's effectively "stuck". Some ships have manual override using a massive wrench, but it takes hours to move the rudder meaningfully in that situation.
As for this:
> 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?
Probably way more than you think. This is a significant reason why they seem so calm when they show up on the bridge. They just hopped from a relatively tiny pilot boat or tug onto a massive ship, possibly with significant sea state. This can be some Indiana Jones level crazy.
https://www.youtube.com/watch?v=18VF8WXWfZw
https://youtu.be/C8ER9Ladqg4?si=Ijwhu90iJi8WPAas&t=226
Pilots are very seasoned mariners who have seen multiple losses of power, and pretty much everything.
Now, back to point 1: bridge team. I have seen a captain the crew trusts execute flawless maneuvers even in exigent circumstances. I have seen a captain the same crew doesn't trust fail repeatedly at everyday things.
We don't have the whole story yet. What happened on the bridge? What happened in the plant? Why did power drop? Did they flood an online generator with diesel oil? I ask because I've seen that happen. Did they blow an exhaust manifold? Seen that. Did they trip the plant by getting preparatory checklist work backward? Seen that. Did they go all back full immediately? Possible that they couldn't ring the order if they dropped power. Was there panic on the bridge (bad sign) or was there grim fortitude to process checklists that would never help (better sign). In any case, no doubt the captain is done. Probably happy to never drive a ship again after that, tbh.
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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…
I had a summer job once, filling trains with sugar. They weighed about 15kkg per wagon (usually 5-10 wagons per train IIRC). One time the pulling cart broke down and we had to switch it for another, but when we took it off the rails we forgot about the "shoe" that is supposed to go between the rail and one of the wheels so it can't move downhill (it was like 1degree of slope so barely recognizable as a slope). It sta…
Trains are very scary stuff even when moving at a crawl.
A 110,000 ton ship collision is something the human brain is just not going to understand intuitively.