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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

#891

Post by pastureofplenty »

inferiorhuman wrote: post #830
CydeWeys wrote: post #598

Earlier quoted context omitted.

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.

All pilots are "harbor pilots". In California, at least, that's not strictly true. They get paid quite handsomely ($400–500k as of a decade ago) to avoid hitting stuff in specific waterways around the Bay Area. https://sfbarpilots.com One had a nasty pill habit and crashed an oil tanker under his purview into the Bay Bridge. https://www.justice.gov/opa/pr/guilty-plea-case-cosco-busan-...

There used to be two really tall redwoods in the beast bay that were used as Navigation Trees to avoid a submerged rock in SF bay, that later had to be blown up after the trees were felled.

https://en.wikipedia.org/wiki/Blossom_Rock_(San_Francisco_Ba...

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

#892

Post by AnarchismIsCool »

boringg wrote: post #864
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…

For an assumption to get a gauge of forces involved: Large cargo ship mass is 190,000 tons @ 8 knots (14.8 kph) - I end up with a Force of about 1.609 * 10^9 or 1.6 GN of force of impact assuming it stopped over a very short distance (1 M). Force comparables (thanks GPT) for scale: Saturn V rocket thrust is about 34 GN on take off. Earthquakes: early stage of the earthquake might have about 1 GN of force in build up.…

I've seen a bunch of weight numbers but it's around a billion joules, the equivalent energy to a Mk83/GBU-32 1000lb bomb (200kg explosive fill).

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

#893

Post by beanjuiceII »

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 ship dropped anchor btw when power Temp came back on as part of its procedure which is why you see the quicker directional change at end

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

#894

Post by keepamovin »

robk wrote: post #884
keepamovin wrote: post #878

Francis Scott Key wrote the Star-Spangled Banner, which later became the US national anthem, while gazing across this same Patapsco river in the morning after a battle and saw that the flag was "still there". On the morning of March 26, 2024, the Bridge in his name was no longer there. Sad. The bridge stood for 47 years and 3 days (17170 days) before destroyed by a trade ship from Asia headed for Indian waters. The t…

LLM for Poetic writing?

Hahm. No, I did it myself. Your LLM detection circuitry needs to be upgraded, sir.

It's sad that people think anything a little 'different' is LLM. Almost exactly as if those takes like "this is LLM" is an LLM-brained take itself haha! :)

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

#895

Post by alsobrsp »

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…

> There wouldn't be a docking pilot on board nor would there be any tugs.

There is likely a pilot onboard until it leaves the Chesapeake, well past the CB Bridge-Tunnel.

When I worked on cruise ships, a pilot boarded a few miles out from the Sunshine Skyway going into Tampa.

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

#896

Post by mannykannot »

lmm wrote: post #844
CydeWeys wrote: post #598

Earlier quoted context omitted.

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.

> All pilots are "harbor pilots". I don't think that's true. The Suez Canal famously requires pilots, but isn't a harbour (I guess you could argue it functions as one). I've heard of pilots for the Great Barrier Reef which is even more not a harbour.

Also the Columbia River Bar Pilots (neither a band nor a drinking club.)

https://www.crmm.org/current-exhibits.html

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

#898

Post by MBCook »

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…

Admittedly very naive question: would they have an anchor? Would it be long enough to hit the channel bed? Could dropping it have helped prevent, or at least slow down, the ship?

Or even if so was it just too late when it all went down and it wouldn’t have made a meaningful difference?

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

#899

Post by somenameforme »

killjoywashere wrote: post #879
araes wrote: post #541

Earlier quoted context omitted.

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…

I've driven a number of vessels, ranging from a 17' dinghy to a nuclear aircraft carrier and have a number of friends who have been involved in accidents one way or another. I have personally not had the conn during disaster, but have been an engineering officer and a legal officer responding to them, on my ship. To be honest, steering a ship under most conditions is not hard. The anxiety-provoking issues are 1) poor…

Quite amazing videos. I've no experience in this domain and so it makes me immediately wonder - is there no risk of substantial damage from those ships colliding due to a wave hitting e.g. the smaller ship just right and pushing it hard against the larger one?

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

#900

Post by gonzo »

jethro_tell wrote: post #825
esaym wrote: post #673

Earlier quoted context omitted.

>entails shutting down the engine and restarting it in reverse. This can be done with a two stroke engine. Funny, I was starting a 2 stroke chainsaw a couple of years ago. I yanked the cord, it kicked back, pulling my arm back down but the saw started up and ran anyway. But it would not cut at all. I killed it and restarted it and noticed the chain going the other (right) way and it was now cutting fine. It has start…

This is actually common for a 2 stroke type engine and used in things like gas golf carts and snow machines. The direction the engine is started is the direction it runs. So to accomplish this for propulsion, you'd add a reverse polarity switch for your starter and you're good to go.

You can even get a (2-stroke) Detroit Diesel to run in reverse.

You don’t want to do it very long, because they don’t make oil pressure in reverse.

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