Author Topic: Baltimore Francis Scott Key Bridge collapse  (Read 48205 times)

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Online tom66Topic starter

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Baltimore Francis Scott Key Bridge collapse
« on: March 26, 2024, 08:28:30 am »
Looks like a major disaster, with many people in the water, after a ship collided with the bridge structure and the bridge collapsed.

https://bbc.co.uk/news/live/world-us-canada-68663071

Fortunately, fatalities are going to be lower just because of the time at night but multiple vehicles and at least a work crew have gone into the water, so almost certainly several will have died.  It's not clear if anyone on board the ship was injured.

Going to be an expensive day for the marine insurers.   I thought bridges like this were designed to resist the collision of a ship? Is this a design fail?  The bridge is, or was, roughly 50 years old, so it's within the range of time that you'd expect considerations like this to have been made.
 

Online SiliconWizard

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #1 on: March 26, 2024, 08:37:12 am »
 :o
 

Offline rsjsouza

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #2 on: March 26, 2024, 08:50:11 am »
What an unfortunate event... The video of the collapse is very impressive - the bridge crumbles as if it was made of paper.

Bridges that collapsed after collisions have happened before and I wouldn't be surprised if negligence or corruption related to its maintenance were critical factors in this case.
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Offline Whales

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #3 on: March 26, 2024, 09:07:33 am »
That brings up an interesting question: are those bridges designed to survive single-ship impacts like that?  We'd hope so, but I wonder if it's actually a requirement.

Offline guenthert

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #4 on: March 26, 2024, 09:12:04 am »
I'm pretty sure that with a massive enough ship sailing fast enough, one could take down any bridge.  I'd think for that reason, there will be limits to what ship and how fast may approach such a bridge.  Were those limits exceeded?
 
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Offline watchmaker

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #5 on: March 26, 2024, 09:48:03 am »
What a thing to wake to!  We lived just outside Baltimore for 40 years.  Sad for the victims, sad for the firemen (FIL led the response to a stadium escalator collapse).   Some USN preposition ships there, port does handle mainly cars (that now screws things up).  City/county/state cannot handle the loss of revenue and jobs.

The Mates and Pilots school is also in Balmer ((hon) and this will a classic case study.

Yeah enough mass at any speed will take down a structure with a direct hit.  Which this appears to have been.  Pilot lost his card unless he had a heart attack.

Holy shit!
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Online Ian.M

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #6 on: March 26, 2024, 10:22:16 am »
See NOAA chart 12281
The main span's piers were in 30' - 35' of water (+ tidal range), and the channel is dredged to 50'.    They were protected by dolphins either side.   To add enough extra dolphins to 'ship-proof' the bridge would be rather expensive, ballpark estimate on the high side of $100 000 000 USD, just for the dolphins and associated protection works, which is at least double the total annual revenue of the port authority, and a significant fraction of the city's budget which is already forecast to have a $180 000 000 annual deficit for the next decade.

The insurers will pay out (eventually) for the cleanup and a depreciated cost for the bridge, and the city and port authority will have to pick up the rest of the tab unless they can get a federal grant.   Ain't nobody going to be happy, as port fees and local taxes will have to go up.   

@Watchmaker,
 Even if the pilot had a medical issue, unless the ship was found to have suffered a critical systems failure, e.g. loss of both throttle and rudder control, Pilot lost his card FULL STOP, either due to responsibility for the incident or by being medically unfit.  At this point (absent such a failure) the pilot and ships' bridge officers on watch are essentially unemployable in any similar role, probably for the rest of their lives.  'Take an oar and walk inland ...'
« Last Edit: March 26, 2024, 10:42:38 am by Ian.M »
 

Offline WatchfulEye

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #7 on: March 26, 2024, 10:36:24 am »
Longer video here. Looks like it shows several episodes of complete electrical failure with the ship drifting.

https://twitter.com/truth68201238/status/1772534441593737582
 

Online tom66Topic starter

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #8 on: March 26, 2024, 10:49:25 am »
Yeah, that's terrible.  Looks like the ship pilots would have been able to do nothing about that, and would have been aware of it the whole time...  Makes you wonder if this is going to be down to whomever maintained that engine/power system last.
 

Online soldar

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #9 on: March 26, 2024, 10:50:49 am »
That brings up an interesting question: are those bridges designed to survive single-ship impacts like that?  We'd hope so, but I wonder if it's actually a requirement.

I think this comment shows a lack of understanding of the scale and proportions of the entire thing. It is pretty much impossible to build that bridge in a way that it could withstand being hit by a mass of, say, 100,000 tons, 150,000 tons etc, going at speed.  And it makes no sense, economic or otherwise.
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Offline vk6zgo

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #10 on: March 26, 2024, 10:54:14 am »
That brings up an interesting question: are those bridges designed to survive single-ship impacts like that?  We'd hope so, but I wonder if it's actually a requirement.

The Tasman bridge in Hobart was hit by a ship in 1975 & several spans collapsed, with the loss of 12 lives.
The pillars on each side of the navigation channel were designed to take a ship impact, but the others where the ship hit weren't.
The "Lake Illawarra" which brought it down was by today's standards, relatively modest in size.
« Last Edit: March 26, 2024, 10:57:55 am by vk6zgo »
 

Offline iMo

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #11 on: March 26, 2024, 11:18:01 am »
From the video above - interesting how fast the ship changed its direction after the first power outage. I would expect the rudders of such a ship will stay in the "last good" direction after the outage.
 

Offline jonpaul

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #12 on: March 26, 2024, 11:21:33 am »
Possible circidian effect on captian of ship at 01:30?

Impact on commerce at the Baliomore port?

Jon

PS: An old  is dierect desendent of Francis Scott Key, composer of our National Anthem.
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Offline Circlotron

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #13 on: March 26, 2024, 11:44:17 am »
That brings up an interesting question: are those bridges designed to survive single-ship impacts like that?  We'd hope so, but I wonder if it's actually a requirement.

The Tasman bridge in Hobart was hit by a ship in 1975 & several spans collapsed, with the loss of 12 lives.
The pillars on each side of the navigation channel were designed to take a ship impact, but the others where the ship hit weren't.
The "Lake Illawarra" which brought it down was by today's standards, relatively modest in size.
Remember it well.


 

Offline watchmaker

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #14 on: March 26, 2024, 11:54:46 am »
Mykid (Structural PE) just told me there was a repair crew on the spans.  Fuck.  Coulda been her.
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Offline NiHaoMike

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #15 on: March 26, 2024, 01:11:38 pm »
From the video above - interesting how fast the ship changed its direction after the first power outage. I would expect the rudders of such a ship will stay in the "last good" direction after the outage.
Is the ship steer by wire? I would expect that most ships are hydraulically steered and in any case, there would be redundant systems like on aircraft.
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Online tom66Topic starter

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #16 on: March 26, 2024, 01:18:58 pm »
From the video above - interesting how fast the ship changed its direction after the first power outage. I would expect the rudders of such a ship will stay in the "last good" direction after the outage.
Is the ship steer by wire? I would expect that most ships are hydraulically steered and in any case, there would be redundant systems like on aircraft.

I'm also wondering why they were so close to the bridge pier.  I'd have thought you'd aim for the middle of the bridge and in the event of a power failure you'd just drift through the middle of the bridge.  It looks like they were quite off course and then simultaneously lost power, a bit of a Swiss cheese event.  I know very little about maritime navigation, but it does seem a bit odd that they even ended up in this position in the first place.
 

Offline Andy Chee

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #17 on: March 26, 2024, 01:35:14 pm »
From the video above - interesting how fast the ship changed its direction after the first power outage. I would expect the rudders of such a ship will stay in the "last good" direction after the outage.
Is the ship steer by wire? I would expect that most ships are hydraulically steered and in any case, there would be redundant systems like on aircraft.
Remember that in order for the rudder to have any effect, the ship needs to be moving relative to the water, or in other words the ship’s propellers must be providing some thrust.

If the ship is moving at zero speed relative to the water i.e. drifting with the current, the rudder does nothing.

In aircraft terminology, if airspeed is zero the aircraft has stalled.
 
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Online Ian.M

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #18 on: March 26, 2024, 01:36:05 pm »
The main span of the bridge was 1100 feet.   MV Dali is approx 160 feet wide, and IRCPS ('COLREGs') Rule 9 states a vessel proceeding along the course of a narrow channel or fairway is obliged to keep "as near to the outer limit of the channel or fairway which lies on her starboard side as is safe and practicable.", so it would be normal practice under a bridge span wide enough for two vessels to pass, to aim for a point that's considerably off-center. 

The vessel would have been carrying considerable way, and in water much shallower than the beam, would require at least six ships lengths to stop from typical manoeuvring speeds, assuming full astern was available, and there was enough lateral searoom to accommodate the severe slew to one side that is typical of a single screw vessel going hard astern.  If the engine failed, low speed steering would be compromised by the lack of forced water flow over the rudder.

Re: WatchfulEye's video link: The observed thick smoke from the funnel implies the engines were rapidly commanded to full speed, and no pilot or watch officer in their right mind would go full ahead towards a near hazard in restricted waters.   Its likely that the slew into the bridge pier was mostly due to going full astern with  insufficient distance to stop.  Dammed if you do, dammed if you don't.
« Last Edit: March 26, 2024, 03:12:19 pm by Ian.M »
 
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Offline NiHaoMike

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #19 on: March 26, 2024, 01:59:26 pm »
The main span of the bridge was 1100 feet.   MV Dali is approx 160 feet wide, and IRCPS ('COLREGs') Rule 9 states a vessel proceeding along the course of a narrow channel or fairway is obliged to keep "as near to the outer limit of the channel or fairway which lies on her starboard side as is safe and practicable.", so it would be normal practice under a bridge span wide enough for two vessels to pass, to aim for a point that's considerably off-center. 
I wonder if that would get revised to aiming for the center as long as there's no traffic in the other direction, to give more room for error.
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Online Ian.M

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #20 on: March 26, 2024, 02:07:05 pm »
No, but its common practice to put markers on a bridge span and have a harbour regulation that vessels shall pass between the markers, which effectively has the same result of excluding non-emergency navigation near the piers.
« Last Edit: March 26, 2024, 02:20:35 pm by Ian.M »
 

Offline TimFox

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #21 on: March 26, 2024, 03:11:22 pm »
The last news report I heard on the radio (9:30 CDT on March 26) said that the container ship had suffered a total loss of propulsion.
The ship notified authorities about the possibility of impact, who were able to reduce the number of people at risk on the bridge before the ship hit it.
 

Offline guenthert

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #22 on: March 26, 2024, 03:34:17 pm »
The main span of the bridge was 1100 feet.   MV Dali is approx 160 feet wide, and IRCPS ('COLREGs') Rule 9 states a vessel proceeding along the course of a narrow channel or fairway is obliged to keep "as near to the outer limit of the channel or fairway which lies on her starboard side as is safe and practicable.", so it would be normal practice under a bridge span wide enough for two vessels to pass, to aim for a point that's considerably off-center. 
I wonder if that would get revised to aiming for the center as long as there's no traffic in the other direction, to give more room for error.

For the landlubbers: starboard is right side, the ship hit the left pylon.

As far as change of rules is concerned, I could see a demand for ships exceeding a 'safe' size be required to be towed into port by tugs, rather than sailing under own power.
« Last Edit: March 26, 2024, 03:40:28 pm by guenthert »
 

Online soldar

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #23 on: March 26, 2024, 04:28:34 pm »
I have sailed my own sailboat on the Chesapeake for quite a few years and know the area well although my main sailing was in the southern part of the Bay.  Lots of stories and memories. I used to love sailing at night.

There can be some strong tidal currents, more so on the southern part, much less so in Baltimore Harbor. I used to know the tides and currents pretty well and use them to my advantage.

As a curiosity, those channels leading up to Baltimore Harbor are marked by "ranges"

Quote
https://en.wikipedia.org/wiki/Leading_lights

Leading lights, also known as range lights in the United States, are a pair of light beacons used in navigation to indicate a safe passage for vessels entering a shallow or dangerous channel; they may also be used for position fixing. At night, the lights are a form of leading line that can be used for safe navigation. The beacons consist of two lights that are separated in distance and elevation, so that when they are aligned, with one above the other, they provide a bearing. Range lights are often illuminated day and night.
Two lights are positioned near one another. One, called the front light, is lower than the one behind, which is called the rear light. At night when viewed from a ship, the two lights only become aligned vertically when a vessel is positioned on the correct bearing. 

The span of the bridge is wider but the width of the dredged channel is about 220m (700') so when the ship hit the bridge it was already outside the channel and had hit the bottom which probably slowed it down considerably.

Remember the ship that got stuck in the Suez canal?  Those large container ships are huge!

If the dredged channel is 220 m wide you have 110 m in each direction and if the ship is about 50 m in beam then it only has 30 m clearance on each side. That is about 1/10th of the length of the ship.

In the attached photo I have marked the edges and center of the channel and what width the ship would be taking.

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Offline TimFox

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #24 on: March 26, 2024, 04:53:19 pm »
Edited from an AP news item (11:24 AM CDT) with further details.

BALTIMORE (AP) — A container ship lost power and rammed into a major bridge in Baltimore early Tuesday, causing the span to buckle into the river below and plunging a construction crew and several vehicles into the dangerously cold waters. Rescuers pulled out two people, but six others were missing.

The ship’s crew issued a mayday call moments before the crash took down the Francis Scott Key Bridge, enabling authorities to limit vehicle traffic on the span, Maryland’s governor said.

The ship struck one of the bridge’s supports, causing the structure to collapse like a toy. It tumbled into the water in a matter of seconds — a shocking spectacle that was captured on video and posted on social media. The vessel caught fire, and thick, black smoke billowed out of it.

With the ship barreling toward the bridge at “a very, very rapid speed,” authorities had just enough time to stop cars from coming over the bridge, Maryland Gov. Wes Moore said.
 

Offline David Hess

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #25 on: March 26, 2024, 05:10:09 pm »
Even if the pilot had a medical issue, unless the ship was found to have suffered a critical systems failure, e.g. loss of both throttle and rudder control, Pilot lost his card FULL STOP, either due to responsibility for the incident or by being medically unfit.  At this point (absent such a failure) the pilot and ships' bridge officers on watch are essentially unemployable in any similar role, probably for the rest of their lives.

It looked like the ship had power failure, and then power failure of the backup system if all of that smoke was from a backup diesel generator.

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Online Ian.M

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #26 on: March 26, 2024, 05:28:24 pm »
I doubt that much smoke would come from a backup generator start.  Usually you get a puff of white smoke from totally unburnt fuel till it fires, then the governor kicks in and throttles back to match the load so not much black smoke.   OTOH if you suddenly throttle up a big diesel running at low speed under load to emergency full throttle, you will get *LOTS* of black smoke, especially if the engine isn't fully warmed up yet.    Whether that was with the engine initially making RPM for 8.5 knots, or was immediately after an engine restart; and whether it was a desperate attempt to get flow over the rudder, or going full astern to take way off, will no doubt come out in the NTSB report.

Meanwhile here's some preliminary analysis from a shipping industry expert:


For the landlubbers: starboard is right side, the ship hit the left pylon.
Not from the ship's point of view.  The ship was proceeding to seaward,  but the video is looking landward, so left side pylon in the video is right (starboard) side as seen from of the ship.  They'd only match if the video was from astern of the ship.

Note that COLREGs rule 9 (part) "as near to the outer limit of the channel or fairway which lies on her starboard side as is safe and practicable."  may not actually be to starboard of the channel centerline if no other vessel is approaching in the opposite direction.  Depending on tidal/current and wind conditions, and the ship's manoeuvring characteristics, keeping port of the centerline to allow additional room to starboard may be prudent.
« Last Edit: March 26, 2024, 06:01:29 pm by Ian.M »
 

Offline cosmicray

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #27 on: March 26, 2024, 05:57:48 pm »
The MV Dali was departing Baltimore, under it's own power, with two harbor pilots on board. Something happened to the power plant (still unclear) and the ship veered off course. Might have been the rudder, or might have been it got caught by the tide without any way to oppose it. There were 7 or 8 people on the bridge repairing potholes, and an unknown number of vehicles.

This reminds me a little of the ship collision in 1980, with the (old) Sunshine Skyway Bridge (across the entrance to Tampa Bay). That accident occurred during a strong rain squall, and the ship had one harbor pilot on board. One (of two spans) collapsed during that accident.

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Offline BrokenYugo

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #28 on: March 26, 2024, 06:30:55 pm »
My only question is how many months/years did this ship have this problem, or some actionable sign of an issue that should have been corrected but instead was allowed to snowball. Every disaster is a long chain or large pile of bad decisions, I'd be shocked if this was the first time it acted up.

I'm sure it will come out in the report, it always does, too bad the people who need to read the reports apparently don't.
 

Offline BILLPOD

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #29 on: March 26, 2024, 07:02:55 pm »
Does Boeing have a a ship building subsidiary :scared:
 
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Online tom66Topic starter

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #30 on: March 26, 2024, 07:10:15 pm »
Apparently the ship radioed a MAYDAY into the port authority and the bridge was closed to traffic before the collision.  This can be seen in the footage, before the ship strikes there is a pronounced gap in traffic.

That is fantastic on the part of the bridge operators, either quick thinking or a well rehearsed safety drill.  Either way, they likely saved countless lives with this action.  Sadly the construction crew stationed on the bridge didn't seem to be aware of the danger, or if they were, they didn't get out in time.  You can see the trucks go down into the river when the collapse happens.
 
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Offline mariush

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #31 on: March 26, 2024, 07:38:10 pm »
Yeah... they tried but couldn't get the ship to stop or turn fast enough

The guy in the video below says they black smoke is the engines running in emergency full reverse and he says the ship also dropped one anchor trying to stop the ship but the anchor was dragging along, and possibly that anchor contributed a bit to ship changing direction a bit but it was in theory a correct move in such scenarios

 

Offline floobydust

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #32 on: March 26, 2024, 07:42:41 pm »
They'd stopped traffic on the bridge but the road crew was still there I guess.
My heart goes out to the dead, crew fixing potholes at 1:30AM on the bridge. What a job to have.

The MV Dali had prior problems and crashed once at an Antwerp dock, it's 9 years old. Who knows how well maintained these container ships are.
The excessive stack smoke might be from the engine not fully supported (air pumps) when the backup generator is running?
The Bow motor really needed to work but sure didn't.
 
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Offline tooki

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #33 on: March 26, 2024, 09:08:05 pm »
A friend of mine in Maryland texted me about this about an hour after it happened. Crazy.

I used to commute across that bridge daily.
 

Offline Bud

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #34 on: March 26, 2024, 09:29:09 pm »
The first thing that came to my mind watching the moment of collapse is the rightmost section of the bridge that also collapsed. Perhaps was not the best bridge design if the entire bridge collapsed because of one section was damaged.
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Offline guenthert

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #35 on: March 26, 2024, 09:35:16 pm »
[..]
For the landlubbers: starboard is right side, the ship hit the left pylon.
Not from the ship's point of view.  The ship was proceeding to seaward,  but the video is looking landward, so left side pylon in the video is right (starboard) side as seen from of the ship.  They'd only match if the video was from astern of the ship.

And I was sure it was.  I saw only the webcam video on youtube ("lifestream") and mistook the lights in background for the port.  An aerial view clears things up: https://www.fox5dc.com/news/aerial-videos-photos-baltimore-francis-scott-key-bridge-collapse

My bad.
 

Online nctnico

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #36 on: March 26, 2024, 09:51:51 pm »
That brings up an interesting question: are those bridges designed to survive single-ship impacts like that?  We'd hope so, but I wonder if it's actually a requirement.

I think this comment shows a lack of understanding of the scale and proportions of the entire thing. It is pretty much impossible to build that bridge in a way that it could withstand being hit by a mass of, say, 100,000 tons, 150,000 tons etc, going at speed.  And it makes no sense, economic or otherwise.
Still, the bridge could have been constructed/designed in a way that only 1 or 2 sections collapse in case of a pylon getting damaged. Now all 4 sections of the bridge collapsed.
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Offline bdunham7

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #37 on: March 26, 2024, 10:09:24 pm »
OTOH if you suddenly throttle up a big diesel running at low speed under load to emergency full throttle, you will get *LOTS* of black smoke, especially if the engine isn't fully warmed up yet.   

This ship has a low-speed direct-drive two-stroke engine that would have required a complete stoppage and reversal of the engine itself.  AFAIK they typically will always be fully preheated with a boiler so it wouldn't be cold, but a full-power reversal/startup would certainly generate some pretty copious smoke.  The heavy fuel they use doesn't help.  Looking at that video I think you may be right in that reversing their single screw violently changed their direction, although I certainly wonder what the rudder issue was.  I guess we'll wait for the reports to come out.
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #38 on: March 26, 2024, 10:32:08 pm »
The first thing that came to my mind watching the moment of collapse is the rightmost section of the bridge that also collapsed. Perhaps was not the best bridge design if the entire bridge collapsed because of one section was damaged.

Still, the bridge could have been constructed/designed in a way that only 1 or 2 sections collapse in case of a pylon getting damaged. Now all 4 sections of the bridge collapsed.

This type of bridge is not redundant.  A single lost section is catastrophic.  This is common to most suspension and truss bridges of this scale.  It is quite hard to imagine how you could build such redundancy into a bridge like this without fundamentally changing its design into something like a cantilever bridge which would require substantially more material.
 
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Offline bdunham7

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #39 on: March 26, 2024, 10:41:35 pm »
I think this comment shows a lack of understanding of the scale and proportions of the entire thing. It is pretty much impossible to build that bridge in a way that it could withstand being hit by a mass of, say, 100,000 tons, 150,000 tons etc, going at speed.  And it makes no sense, economic or otherwise.

It's pretty common to have islands of large fill around the piers.  The island can be mostly underwater as it is sufficient to have the ship run aground before it gets to the bridge itself. 
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #40 on: March 26, 2024, 10:45:14 pm »
Thread from bridge designer Matt Dursh

https://twitter.com/MattDursh/status/1772605870599238112

Quote
Bridge design for vessel collision.  A🧵
The main span of the Francois Scott Key Bridge is 1300 ft. It also has 185 ft of clearance, making this a massive bridge.
This type of bridge is considered complex.
Baltimore is in for a long haul before replacement. Here is why.
We design modern bridges for ship impact, but this was not always the case.
In 1980 the Sunshine Skyway Bridge also collapsed from vessel strike.
The photo below is the original Skyway.  Similar bridges and identical failure.
The Skyway collapse changed bridge design.
The Baltimore bridge collapsed because it got hit by container ship. What failed first?
It appears the bow of the ship made contact with the vertical columns that supported the truss superstructure, causing it to have a cascade failure.
This bridge was going to fail from this event. It simply was not designed for an equivalent static force that is well over 3 million pounds.
The container ship, assuming the navigation channel is centered, veered over 500 feet off course.
Why did the whole thing fall?
The whole truss fell because this is a continuous bridge.
This means that the 3 span unit behaves as as one. If one span fails, the maximum dead loads redistributes.
This provides benefits to load resistance and is how we design modern bridges for this.
How?
Modern bridges deal with vessel collision two ways.
The first is to use a dolphin.
This is a mass of rock, sand, and steel that serves to stop the vessel before it makes contact with the bridge.
Likely the new bridge replacement will use a dolphin as one method.
The second is to design the bridge to take the vessel strike and resist the event.
This is a massive undertaking with a central focus: don't collapse.
We will see localized failures, but maintain global stability.
This load could be well over 3 million pounds.
To resist that much load to stop a vessel, we need a flexible bridge and a lot of foundations, such as piling or drilled shafts.
Typically this is more foundation needed than to simply resist earthquakes, hurricanes, and every day loads.
So where do we go from here?
Baltimore is going to be without a critical bridge for a long time.
Tampa's Skyway bridge took 7 years, but this will be done sooner, hopefully much sooner.
What needs to be done?  Well, a lot.
Can the approach spans be salvaged? 
The approach spans are likely fine.
But are they tall enough to support the new main span? Does the bridge need more vertical clearance?
Officials will nees to ask... do they fully replace the bridge in full, or attempt to reopen sooner with only the main span?
The main span is not easy to design or build, unless they make a decision to go to a smaller span bridge (less than 375ft).
But that comes with new challenges particularly with how close the piers will be to the navigation channel.
There are many things left to talk about here, but on a plane now.
I specialize in bridge design of long bridges over navigable waters.
Thanks for reading and happy to answer all questions.
 
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Offline bdunham7

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #41 on: March 26, 2024, 10:45:59 pm »
Here's a photo of the bridge with the intended path in green and the actual path in red.  Not particularly accurate, just a rough hand drawing.  Quite the sharp turn and very unlucky.
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #42 on: March 26, 2024, 10:51:42 pm »
Indeed, very unlucky.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #43 on: March 26, 2024, 10:52:16 pm »
It's pretty common to have islands of large fill around the piers.  The island can be mostly underwater as it is sufficient to have the ship run aground before it gets to the bridge itself.
All the modern big bridges have those islands around the piers. They will certainly lead to a modest sized ship running aground in a fairly harmless way. Whether they are effective against a really big container ship is another matter.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #44 on: March 26, 2024, 10:54:07 pm »
Apparently the ship radioed a MAYDAY into the port authority and the bridge was closed to traffic before the collision.  This can be seen in the footage, before the ship strikes there is a pronounced gap in traffic.
That is fantastic on the part of the bridge operators, either quick thinking or a well rehearsed safety drill.  Either way, they likely saved countless lives with this action.  Sadly the construction crew stationed on the bridge didn't seem to be aware of the danger, or if they were, they didn't get out in time.  You can see the trucks go down into the river when the collapse happens.

Yes, really fantastic effort here if that's the case.
There wouldn't be any local "bridge operator" who could run out with witches hats and signs though right? Are there electronic signs they can just switch on warning people instantly? I pressume so.
Very sad about the construction crew and anyone else caught up in this.

EDIT: Yes, they have electonic signs.
« Last Edit: March 26, 2024, 10:56:32 pm by EEVblog »
 
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Offline Sal Ammoniac

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #45 on: March 26, 2024, 11:07:47 pm »
That brings up an interesting question: are those bridges designed to survive single-ship impacts like that?  We'd hope so, but I wonder if it's actually a requirement.

I think this comment shows a lack of understanding of the scale and proportions of the entire thing. It is pretty much impossible to build that bridge in a way that it could withstand being hit by a mass of, say, 100,000 tons, 150,000 tons etc, going at speed.  And it makes no sense, economic or otherwise.


The San Francisco Bay Bridge was hit by a ship similar in size to the ship that hit the Key Bridge and the damage to the bridge was minimal. This was an ecological disaster due to the collision spilling 50,000 gallons of bunker oil into the bay, but no injuries on the bridge or on the ship.
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #46 on: March 26, 2024, 11:11:13 pm »
Still, the bridge could have been constructed/designed in a way that only 1 or 2 sections collapse in case of a pylon getting damaged. Now all 4 sections of the bridge collapsed.
That makes no sense. It is a single bridge, designed and built as a whole. It is not three bridges.

In any case. If the channel span falls it makes no difference: the channel is blocked and the vehicular deck above is blocked. The result is the same: both the maritime channel and the road above are unusable.

This is a one in a billion occurrence. If the ship had lost power a minute earlier it would not have reached the bridge and if it had lost it a minute later it would have been past the bridge.

In my estimation removing the wreck of the bridge is the most urgent task so that maritime traffic can be restored. We shall see how long that takes but I am generally quite impressed by how quick the feds deal with this kind of thing.

Vehicular traffic still has a tunnel under the Bay a bit farther north and another bridge a bit to the south so, while inconvenient, it is not terribly bad.

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #47 on: March 26, 2024, 11:12:08 pm »
Apparently the ship radioed a MAYDAY into the port authority and the bridge was closed to traffic before the collision.  This can be seen in the footage, before the ship strikes there is a pronounced gap in traffic.
That is fantastic on the part of the bridge operators, either quick thinking or a well rehearsed safety drill.  Either way, they likely saved countless lives with this action.  Sadly the construction crew stationed on the bridge didn't seem to be aware of the danger, or if they were, they didn't get out in time.  You can see the trucks go down into the river when the collapse happens.

Yes, really fantastic effort here if that's the case.
There wouldn't be any local "bridge operator" who could run out with witches hats and signs though right? Are there electronic signs they can just switch on warning people instantly? I pressume so.
Very sad about the construction crew and anyone else caught up in this.

EDIT: Yes, they have electonic signs.

Imagine being that one guy who blew past the 'STOP DO NOT ENTER' sign because "ehhh I can make it"... 

A system like this is installed in a tunnel in Sydney, not sure if anywhere else uses it for a bridge. Tunnels justify its use more often due to their greater risks (I imagine daylight vs dark tunnel makes it more difficult too).
 
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #48 on: March 26, 2024, 11:16:00 pm »
They had two minutes warning:
https://www.bbc.com/news/live/world-us-canada-68663071

Quote
Ship hit bridge two minutes after mayday call
The pilot steering the Dali made a mayday call to authorities roughly two minutes before the ship collided with the bridge, Baltimore County Executive John Olszewski has said.
We also have some new details about what happened onboard, with BBC's US partner CBS News saying multiple officials confirmed the Dali crew had tried to drop an anchor to stop the ship.
It's not clear if they were able to successfully deploy the anchor.
For those wondering why tug boats were not guiding the Dali, it's because tugs are not required to escort ships under the bridge.
They are used mainly to get ships in and out of the docking station in the Port of Baltimore.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #49 on: March 26, 2024, 11:19:54 pm »
Imagine being that one guy who blew past the 'STOP DO NOT ENTER' sign because "ehhh I can make it"... 
A system like this is installed in a tunnel in Sydney, not sure if anywhere else uses it for a bridge. Tunnels justify its use more often due to their greater risks (I imagine daylight vs dark tunnel makes it more difficult too).


That has been activiated quite a few times in Sydney. Tall trucks getting stuck are not that uncommon, and you don't want cars piling up in the tunnel due to exhaust. IIRC they have a height detection system now and that water barrier activiates automatically if a tall truck tries to enter.
Of course, worst case activiation would be a harbour tunnel leak.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #50 on: March 26, 2024, 11:32:30 pm »
The San Francisco Bay Bridge was hit by a ship similar in size to the ship that hit the Key Bridge and the damage to the bridge was minimal. This was an ecological disaster due to the collision spilling 50,000 gallons of bunker oil into the bay, but no injuries on the bridge or on the ship.
Well, yes, but... In this case they built the bridge the way they did and I assume they had their reasons. Probably cost was a major consideration. Probably today it might be done quite differently. To make a large enough island to protect the supports you might have had to widen the span of the bridge more than was considered economical or practical at the time of it's design.

I mean, I tend to trust the people who designed it because they had the knowledge and information. I try not to second guess unless the flaws or faults are blatantly clear and obvious.

At the time the engineers thought it was a reasonable compromise and the fact that it has gone for so many decades without this accident kind of supports their choice. It is a one in a million chance and if it did not happen this time the bridge would most likely have served its life without a similar thing happening.

Engineers have to make choices with how to best use the budget they are given and after any accident there will be those who will say it could have been prevented if only they had spent more on this or that. It is just not economical to try to prevent everything that could possibly happen. Note also that the ship was already outside of the dredged channel and running aground (and slowing down).

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #51 on: March 26, 2024, 11:40:37 pm »
Any info on how the steering system of the ship works? I'm surprised it doesn't have enough redundancy to prevent this, in particular a backup turbine (analogous to the RAT on an aircraft) powered by the momentum of the ship itself.
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #52 on: March 26, 2024, 11:48:36 pm »
Any info on how the steering system of the ship works? I'm surprised it doesn't have enough redundancy to prevent this, in particular a backup turbine (analogous to the RAT on an aircraft) powered by the momentum of the ship itself.

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #53 on: March 27, 2024, 12:17:10 am »
Any info on how the steering system of the ship works? I'm surprised it doesn't have enough redundancy to prevent this, in particular a backup turbine (analogous to the RAT on an aircraft) powered by the momentum of the ship itself.
I guess it is most probably hydraulic and I think an emergency engine and pump would make more sense. I live next to a hospital and as soon as the electric power fails an emergency generator starts automatically. On a ship that size I would expect a standby system that guarantees the proper working of all essential functions. It may be that the ship did have them but they were not adequately maintained.

I am always surprised by how emergency systems are not functional when needed. Like when there is a fire in a crowded place and the emergency exits are locked and people die.
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #54 on: March 27, 2024, 12:33:51 am »
The Skyway collapse changed bridge design.

The Sunshine Skyway Bridge (entrance to Tampa Bay) came down in 1980. The FSK Bridge (that collapsed today) was built during the 1970s, so before the Skyway lessons were learned. The Sunshine Skyway Bridge (the current one) has dolphins surrounding the support columns. We live and we learn. The original Skyway Bridge lasted about ~25 years (originally there was a single span, then a second was added). The FSK Bridge survived for ~50 years. Properly taken care of, it might be still standing, other than for the vessel collision.

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #55 on: March 27, 2024, 12:40:33 am »
In my estimation removing the wreck of the bridge is the most urgent task so that maritime traffic can be restored. We shall see how long that takes but I am generally quite impressed by how quick the feds deal with this kind of thing.

Vehicular traffic still has a tunnel under the Bay a bit farther north and another bridge a bit to the south so, while inconvenient, it is not terribly bad.

US Army Corp of Engineers has been tasked with restoring the shipping channel, which includes the removal of the wreckage. I'm assuming they will be working with the owner of the ship and the port of Baltimore, to have the ship carefully withdrawn from the accident location.

Somewhere today it was mentioned that hazardous cargo that could cross the bridge, may not be allowable in the tunnel. So that is a complication that needs to be sorted out.
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #56 on: March 27, 2024, 12:52:18 am »
US Army Corp of Engineers has been tasked with restoring the shipping channel, which includes the removal of the wreckage. I'm assuming they will be working with the owner of the ship and the port of Baltimore, to have the ship carefully withdrawn from the accident location.

Somewhere today it was mentioned that hazardous cargo that could cross the bridge, may not be allowable in the tunnel. So that is a complication that needs to be sorted out.
I had not thought of hazmat but in the big scheme of things those vehicles can go around. Still, it the Key bridge being out of service will mean additional traffic on the other bridge and the tunnel and may lead to traffic jams, etc.

I would think getting the ship out of the way is the easier part and removing the wreckage of the bridge is more complicated. Or maybe not. I suppose the first thing is to get everything out of the channel and not necessarily out of the water.

I wonder how hard aground the ship is. I am reminded of the Evergrande ship that went aground in the Suez canal and they had quite a hard time getting it afloat again.

As for the wreckage of the bridge, I suppose it can be cut up so it  is easier to move. Still, quite a task.

But clearing the channel and making it navigable again is, in my view, the most urgent task with great difference. Lots of ships are waiting to get out and to get in and waiting idle costs money.
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #57 on: March 27, 2024, 01:18:17 am »
Well, yes, but... In this case they built the bridge the way they did and I assume they had their reasons. Probably cost was a major consideration. Probably today it might be done quite differently. To make a large enough island to protect the supports you might have had to widen the span of the bridge more than was considered economical or practical at the time of it's design.
I mean, I tend to trust the people who designed it because they had the knowledge and information. I try not to second guess unless the flaws or faults are blatantly clear and obvious.
At the time the engineers thought it was a reasonable compromise and the fact that it has gone for so many decades without this accident kind of supports their choice. It is a one in a million chance and if it did not happen this time the bridge would most likely have served its life without a similar thing happening.

That would be my guess as well.
Engineering is the art of practical compromise.

« Last Edit: March 27, 2024, 01:57:10 am by EEVblog »
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #58 on: March 27, 2024, 01:35:55 am »
That would be my guess as well.
Engineering the art of compromise.
Also, safety is a relative and changing concept. In the late 19th century, in the age of sail, it was considered quite normal to lose a sailor or two on a long voyage. they climbed the rigging and accidents were common. If a sailor fell on deck he was probably dead or maimed for life. If he fell in the water the chances of recovering him were slim... even if they tried and many times they didn't because it might be considered too risky with little chance of recovering him.

Up into the 1930s building bridges and other structures the risk of death was just considered part of the job. No safety equipment and no real accident prevention. It was a very different mentality.

Today we build a tunnel and it is two tunnels plus one or two service tunnels, etc. And build with much greater safety in mind. The culture has changed. Electrical appliances and installations from 60, 80, 100 years ago were extremely dangerous by the standards of today.

It is easy to see how the mentality of safety in general has changed in developed nations. Just go to some third world countries and you still see a mentality that any money or effort expended in safety and prevention is money and effort wasted.

Safety costs money and it is good if you can pay for it. The richer we become the more safety we can afford. Which is good.
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #59 on: March 27, 2024, 01:40:06 am »
I notice an electric line running parallel to the bridge and the pylons are well protected by caissons. Still, they are in shallower water, farther away from the dredged channel. If they were hit by a ship that size I doubt they would survive.
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #60 on: March 27, 2024, 01:49:54 am »
Closeup view of crash.  The ship appears to have it's power go off and on 3 times up to the crash...


Areal reconnaissance the next day.

 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #61 on: March 27, 2024, 01:53:50 am »
Safety costs money and it is good if you can pay for it. The richer we become the more safety we can afford. Which is good.

But there is still going to be practical compromise at some point, that six sigma does only get you so far.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #62 on: March 27, 2024, 06:12:26 am »
The San Francisco Bay Bridge was hit by a ship similar in size to the ship that hit the Key Bridge and the damage to the bridge was minimal. This was an ecological disaster due to the collision spilling 50,000 gallons of bunker oil into the bay, but no injuries on the bridge or on the ship.

That was a mere side-swipe or glancing blow -- not a head-on crash.  The Bay Bridge pylon gouged the side of the hull.  Up close the Bay Bridge pylons are rugged-looking but I doubt that they could withstand a bad direct collision.
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #63 on: March 27, 2024, 07:02:10 am »
The regs say the ship should have steering back within 45 seconds by emergency power.
Looks like it takes more than a minute for power to recover.

These ships have massive power plants. Looks like they have four ~4 MW generators. They're big, I worked on some.
And depending on the amount of reefers they're running multiple generators are in parallel all the time. I'm not sure if they can run the main engine on emergency power alone, that is typically only to get one of the four others running.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #64 on: March 27, 2024, 07:38:26 am »
In Tasmania they stop traffic when a large ship goes under:
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #65 on: March 27, 2024, 07:40:50 am »
The regs say the ship should have steering back within 45 seconds by emergency power.
Looks like it takes more than a minute for power to recover.
These ships have massive power plants. Looks like they have four ~4 MW generators. They're big, I worked on some.
And depending on the amount of reefers they're running multiple generators are in parallel all the time. I'm not sure if they can run the main engine on emergency power alone, that is typically only to get one of the four others running.

I heard on an interview with an expert on large ship navigation that the port thusters at full power can overload the generators and cause a complete loss of power.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #66 on: March 27, 2024, 08:36:34 am »
The regs say the ship should have steering back within 45 seconds by emergency power.
Looks like it takes more than a minute for power to recover.
These ships have massive power plants. Looks like they have four ~4 MW generators. They're big, I worked on some.
And depending on the amount of reefers they're running multiple generators are in parallel all the time. I'm not sure if they can run the main engine on emergency power alone, that is typically only to get one of the four others running.

I heard on an interview with an expert on large ship navigation that the port thusters at full power can overload the generators and cause a complete loss of power.

That seems like poor design.  Surely those thrusters should be electronically limited when on emergency power, or the circuit breaker to the thrusters should trip before killing the generator too.  The last thing you need in a situation like this is losing electric power as well as steering, as it will disorient you at night.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #67 on: March 27, 2024, 08:43:21 am »
The regs say the ship should have steering back within 45 seconds by emergency power.
Looks like it takes more than a minute for power to recover.
These ships have massive power plants. Looks like they have four ~4 MW generators. They're big, I worked on some.
And depending on the amount of reefers they're running multiple generators are in parallel all the time. I'm not sure if they can run the main engine on emergency power alone, that is typically only to get one of the four others running.

I heard on an interview with an expert on large ship navigation that the port thusters at full power can overload the generators and cause a complete loss of power.

Yes, to operate thruster they will need more than 1 generator, often 3. Thrusters are awful for generators. They can take all the load in several seconds, and then also dump it. Wiki says the thruster is 3000 kW. That's challenging.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #68 on: March 27, 2024, 11:46:43 am »
Maybe the reason for the curve the ship took was trying to run it into the dolphins. It's terrible the ship passed all the dolphins and got stuck exactly at the bridge pillar. The pillar should have been in the "shadow" of the dolphins.

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #69 on: March 27, 2024, 12:31:19 pm »
Maybe the reason for the curve the ship took was trying to run it into the dolphins. It's terrible the ship passed all the dolphins and got stuck exactly at the bridge pillar. The pillar should have been in the "shadow" of the dolphins.

Regards, Dieter
What? This makes no sense at all.

There were no dolphins.

The ship was out of control. If they had any control they would have gone under the bridge.

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Offline bdunham7

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #70 on: March 27, 2024, 02:11:31 pm »
There were no dolphins.

There are, visible here in Bing maps and in my earlier photo.  Oddly they aren't visible in Google maps satellite view.

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Offline ejeffrey

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #71 on: March 27, 2024, 03:24:15 pm »
That would be my guess as well.
Engineering is the art of practical compromise.

Also the size of container ships has probably increased since the bridge was designed.  It doesn't sound like the bridge was designed to take a large direct impact in any case but even if it was designed for a typical ship from the 60s and 70s, it might not have been enough.  You try to plan ahead when you design a major civil engineering project but you can't necessarily plan for every thing that could happen in 50 years.
 

Offline fourfathom

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #72 on: March 27, 2024, 03:26:26 pm »
Any info on how the steering system of the ship works? I'm surprised it doesn't have enough redundancy to prevent this, in particular a backup turbine (analogous to the RAT on an aircraft) powered by the momentum of the ship itself.

On any vessel with a rudder, there needs to be water flowing past the rudder for steerage.  At low speeds, this flow is provided by the propeller.  Once that flow diminishes the rudder becomes ineffective (especially with the relatively small rudders you find on large ships).  And if you are trying to back up, a working propeller can no longer force water over the rudder, making steering even more difficult.  In this case you get "prop walk" caused by the asymmetrical water flow around the propellor (the top side is close to the hull, the bottom side is not), and this pushes the stern sideways more than the rudder can compensate for.  I believe we saw this in the video.  Also, apparently they were dragging an anchor (ships anchors are generally too small to be of much use in this type of situation), and this also made any rudder steering control much less effective.

Some ships have propellers on steerable pods, bow and stern, and/or bow and stern thrusters (mounted for sideways maneuvering thrust) but I understand that this ship only had one propeller (screw) and a rudder.
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Offline switchabl

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #73 on: March 27, 2024, 05:31:59 pm »
Some ships have propellers on steerable pods, bow and stern, and/or bow and stern thrusters (mounted for sideways maneuvering thrust) but I understand that this ship only had one propeller (screw) and a rudder.

As well as a single 3000 kW bow thruster according to Wikipedia.
https://en.wikipedia.org/wiki/MV_Dali#Description

Not likely to have any relevant effect at 8 kts though.
 

Offline fourfathom

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #74 on: March 27, 2024, 06:14:10 pm »
Some ships have propellers on steerable pods, bow and stern, and/or bow and stern thrusters (mounted for sideways maneuvering thrust) but I understand that this ship only had one propeller (screw) and a rudder.

As well as a single 3000 kW bow thruster according to Wikipedia.
https://en.wikipedia.org/wiki/MV_Dali#Description

Not likely to have any relevant effect at 8 kts though.

I was not aware of the bow thruster -- should have checked first.  Thanks!
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Offline tooki

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #75 on: March 27, 2024, 06:22:19 pm »
Apparently the ship radioed a MAYDAY into the port authority and the bridge was closed to traffic before the collision.  This can be seen in the footage, before the ship strikes there is a pronounced gap in traffic.
That is fantastic on the part of the bridge operators, either quick thinking or a well rehearsed safety drill.  Either way, they likely saved countless lives with this action.  Sadly the construction crew stationed on the bridge didn't seem to be aware of the danger, or if they were, they didn't get out in time.  You can see the trucks go down into the river when the collapse happens.

Yes, really fantastic effort here if that's the case.
There wouldn't be any local "bridge operator" who could run out with witches hats and signs though right? Are there electronic signs they can just switch on warning people instantly? I pressume so.
Very sad about the construction crew and anyone else caught up in this.

EDIT: Yes, they have electonic signs.
In addition to the electronic signage, there is the toll booth area on the east approach (for both directions) that could have stopped westbound traffic. But additionally, due to the roadwork being done, there were apparently traffic flaggers present. I don’t know whether they were the ones who actually stopped traffic.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #76 on: March 27, 2024, 07:13:58 pm »
There were no dolphins.
There are, visible here in Bing maps and in my earlier photo.  Oddly they aren't visible in Google maps satellite view.
I believe they are intended more as navaids as they have lights and they are not really placed as dolphins and they are not massive enough to serve that purpose for any large ship.

They would be useless for a ship that size. I suppose they could serve to stop small speedboats or such.

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #77 on: March 27, 2024, 07:19:16 pm »
Some ships have propellers on steerable pods, bow and stern, and/or bow and stern thrusters (mounted for sideways maneuvering thrust) but I understand that this ship only had one propeller (screw) and a rudder.
This YouTube channel shows time lapse videos of cruise ships arriving and departing Miami and... not a single tug.



« Last Edit: March 27, 2024, 07:26:08 pm by soldar »
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Offline tooki

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #78 on: March 27, 2024, 07:39:32 pm »
Also the size of container ships has probably increased since the bridge was designed. 
Not “probably”. A better word is “dramatically”. The Dali is a roughly 10000-TEU ship. (TEU = twenty-foot equivalent units) That’s 4x the size of the biggest container ships in existence when the Key Bridge’s construction began in 1972. And a fraction of the size of the biggest ships today, which currently top out at 24,000 TEU!
 
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #79 on: March 27, 2024, 07:42:08 pm »
Some ships have propellers on steerable pods, bow and stern, and/or bow and stern thrusters (mounted for sideways maneuvering thrust) but I understand that this ship only had one propeller (screw) and a rudder.
This YouTube channel shows time lapse videos of cruise ships arriving and departing Miami and... not a single tug.
I don't think that is a fair comparison. Cruise ships hop short distances from harbour to harbour including relatively small harbours. Freight ships OTOH travel much longer distances and are much more cost sensitive so it makes sense to equip a ship with the minimum necessary features. Keep in mind that what isn't on a ship, can't get broken  :)
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #80 on: March 27, 2024, 07:47:25 pm »
I don't think that is a fair comparison. Cruise ships hop short distances from harbour to harbour including relatively small harbours. Freight ships OTOH travel much longer distances and are much more cost sensitive so it makes sense to equip a ship with the minimum necessary features. Keep in mind that what isn't on a ship, can't get broken  :)
Um... I wasn't comparing anything. Only pointing out that thrusters exist and can be used usefully.
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #81 on: March 27, 2024, 08:17:42 pm »
Also the size of container ships has probably increased since the bridge was designed. 
Not “probably”. A better word is “dramatically”. The Dali is a roughly 10000-TEU ship. (TEU = twenty-foot equivalent units) That’s 4x the size of the biggest container ships in existence when the Key Bridge’s construction began in 1972. And a fraction of the size of the biggest ships today, which currently top out at 24,000 TEU!

I am curious how much of an improvement such container ships are.  Ultimately the TEU-per-day figures are what matter for a port.

I would presume the reason they exist is they have better fuel economy, and fuel is the biggest operating expense for a ship like this.  Are they better in other ways, such as overall logistics capacity?  Or, would it be better to have more smaller ships?

If it is a case where these ships offer, for instance, 5% better fuel consumption per container-km, it could be argued that society is bearing the cost of these ships in other ways (Suez Canal blockage would not have been possible without the Ever Given for instance, 20kTEU capacity) and governments should be thinking carefully about this.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #82 on: March 27, 2024, 08:25:02 pm »
There are, visible here in Bing maps and in my earlier photo.  Oddly they aren't visible in Google maps satellite view.

Also visible in earlier Google Earth photos
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Offline bdunham7

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #83 on: March 27, 2024, 08:31:48 pm »
I believe they are intended more as navaids as they have lights and they are not really placed as dolphins and they are not massive enough to serve that purpose for any large ship.

They would be useless for a ship that size. I suppose they could serve to stop small speedboats or such.

Hmmm, small speedboats?  The reinforced concrete part that is out of the water is over 5 meters in diameter and presumably there is much more below the water.  They are placed over 50 meters from the main bridge piers.  I'm pretty sure that would stop a medium, or even a large speedboat!  But since the Dali bypassed them entirely, we'll never know for sure.  I'm betting that if even a large cargo ship hit them at a shallow angle as they anticipated, it probably wouldn't reach the bridge piers.  But without knowing the subsea profile around those, its hard to say.
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Offline floobydust

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #84 on: March 27, 2024, 08:46:24 pm »
That would be my guess as well.
Engineering the art of compromise.
Also, safety is a relative and changing concept. In the late 19th century, in the age of sail, it was considered quite normal to lose a sailor or two on a long voyage. they climbed the rigging and accidents were common. If a sailor fell on deck he was probably dead or maimed for life. If he fell in the water the chances of recovering him were slim... even if they tried and many times they didn't because it might be considered too risky with little chance of recovering him.

Up into the 1930s building bridges and other structures the risk of death was just considered part of the job. No safety equipment and no real accident prevention. It was a very different mentality.

Today we build a tunnel and it is two tunnels plus one or two service tunnels, etc. And build with much greater safety in mind. The culture has changed. Electrical appliances and installations from 60, 80, 100 years ago were extremely dangerous by the standards of today.

It is easy to see how the mentality of safety in general has changed in developed nations. Just go to some third world countries and you still see a mentality that any money or effort expended in safety and prevention is money and effort wasted.

Safety costs money and it is good if you can pay for it. The richer we become the more safety we can afford. Which is good.

I say nope. Profit is priority #1. Engineering is not so important. Ref. Boeing.
It's a toll bridge that makes a shit ton of money $56M last year. They even sell bonds. It's a big fat cash cow. I'm sure it's paid for itself a few times over its lifetime.

Could they not afford tugboat escorts? Upgrades would not useful, no bridge can withstand a fully loaded container ship nailing it.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #85 on: March 27, 2024, 11:32:20 pm »
In a previous life I had a bit to do with cargo ships.

The number that broke down or had inoperable things like bow thrusters was surprising.  It is probably why they were mostly registered in some third world country.
 
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Offline JustMeHere

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #86 on: March 27, 2024, 11:52:39 pm »
Apparently the ship radioed a MAYDAY into the port authority and the bridge was closed to traffic before the collision.  This can be seen in the footage, before the ship strikes there is a pronounced gap in traffic.
That is fantastic on the part of the bridge operators, either quick thinking or a well rehearsed safety drill.  Either way, they likely saved countless lives with this action.  Sadly the construction crew stationed on the bridge didn't seem to be aware of the danger, or if they were, they didn't get out in time.  You can see the trucks go down into the river when the collapse happens.

Yes, really fantastic effort here if that's the case.
There wouldn't be any local "bridge operator" who could run out with witches hats and signs though right? Are there electronic signs they can just switch on warning people instantly? I pressume so.
Very sad about the construction crew and anyone else caught up in this.

EDIT: Yes, they have electonic signs.
In addition to the electronic signage, there is the toll booth area on the east approach (for both directions) that could have stopped westbound traffic. But additionally, due to the roadwork being done, there were apparently traffic flaggers present. I don’t know whether they were the ones who actually stopped traffic.

The police stopped the traffic.  This is well documented.  (https://www.foxnews.com/video/6349808520112).  Also there are no toll booths on this bridge (https://www.google.com/maps/place/Francis+Scott+Key+Bridge,+Maryland/@39.2298883,-76.5108951,319m/data=!3m1!1e3!4m6!3m5!1s0x89c80052ddeb3cad:0xf3fb8c8f100a3e9e!8m2!3d39.2323329!4d-76.5063164!16zL20vMDR2Njgw!5m1!1e4?entry=ttu)
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #87 on: March 28, 2024, 12:16:15 am »
I say nope. Profit is priority #1. Engineering is not so important. Ref. Boeing.
It's a toll bridge that makes a shit ton of money $56M last year. They even sell bonds. It's a big fat cash cow. I'm sure it's paid for itself a few times over its lifetime.

Those cargo ships, as .RC. also confirms, are the epitome of favoring profits over anything else, being extremely polluting and transporting cheap goods all over the world that are of dubious quality and manufactured in dubious conditions for a bottom-low cost.
So really, I don't know how we can even be surprised.
 

Offline vk6zgo

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #88 on: March 28, 2024, 12:20:38 am »
In a previous life I had a bit to do with cargo ships.

The number that broke down or had inoperable things like bow thrusters was surprising.  It is probably why they were mostly registered in some third world country.

Back in the 1950s/60s the regulation of such things in Australian ports was very strict, to the point of harshness.
Ships suspected of not meeting the safety standards, (usually back then, those registered in Panama), would undergo a "snap" inspection.

If they didn't meet the requirements, they were asked nicely to fix things, & in the meantime they could not leave the port.
The "Sheriff's Officer"* would nail (in reality, tape) a notice to the mast, officially arresting the ship.
If they still didn't fix it, the fines started to apply.

*Yes, Virginia, we do have Sheriff's, but they don't lead posses chasing "owlhoots", they are "Officers of the Court", who in turn have minions who do such things as arresting ships.
 

Offline floobydust

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #89 on: March 28, 2024, 12:22:22 am »
[...] Also there are no toll booths on this bridge [...][/url])

"All eight Maryland Transportation Authority (MDTA) facilities are all electronic (cashless). With All Electronic Tolling (AET), drivers do not stop or slow down to pay tolls. Instead, they are collected through E-ZPass, Pay-By-Plate, and Video Tolling...." source {mysteriously offline for a while now}

I wonder if this disaster is out of the woods? The ship is stuck on top of the concrete pier, full 1.5M gal of fuel, has a history of structural damage from crashing into a dock years ago. Yeah good luck there. At least it's not on fire.
It's said the ship had electrical problems for two days while docked and they're suspecting contaminated fuel as another problem.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #90 on: March 28, 2024, 12:47:24 am »
At least it's not on fire.
Yet/so-far.
 

Offline johansen

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #91 on: March 28, 2024, 01:41:12 am »
I would presume the reason they exist is they have better fuel economy, and fuel is the biggest operating expense for a ship like this.  Are they better in other ways, such as overall logistics capacity?  Or, would it be better to have more smaller ships?

If it is a case where these ships offer, for instance, 5% better fuel consumption per container-km, it could be argued that society is bearing the cost of these ships in other ways (Suez Canal blockage would not have been possible without the Ever Given for instance, 20kTEU capacity) and governments should be thinking carefully about this.
I don't think the ships are going to get much bigger than they are now, because at some point the lowest natural resonance frequency of the largest boats, which is already on the order of 1 second.. results in a problem where the waves can split the ship in half. bigger ship would require more steel which means your improvements in hull speed are offset by the ratio of dead to full load.

 

Offline JustMeHere

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #92 on: March 28, 2024, 02:08:28 am »
I would presume the reason they exist is they have better fuel economy, and fuel is the biggest operating expense for a ship like this.  Are they better in other ways, such as overall logistics capacity?  Or, would it be better to have more smaller ships?

If it is a case where these ships offer, for instance, 5% better fuel consumption per container-km, it could be argued that society is bearing the cost of these ships in other ways (Suez Canal blockage would not have been possible without the Ever Given for instance, 20kTEU capacity) and governments should be thinking carefully about this.
I don't think the ships are going to get much bigger than they are now, because at some point the lowest natural resonance frequency of the largest boats, which is already on the order of 1 second.. results in a problem where the waves can split the ship in half. bigger ship would require more steel which means your improvements in hull speed are offset by the ratio of dead to full load.

The size of the ships are limited by canal locks and the bridges it will encounter.   The ship class is often incorporated into the name. Ex: Panamax 366m.  400m.appears to be the current size limit.  These ships cannot enter the Panama Canal though  .
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #93 on: March 28, 2024, 02:18:57 am »
I don't think it's a question of cost vs safety.  It's a question of mass.  The more mass added to a bridge means the more additional mass that is needed to stop the bridge from collapsing under its own weight.

At some point making the bridge stronger adds more weight to the point the bridge can't be made any stronger.  (My university roommates were civil engineers, and I remember discussing this exact subject with them.)

Space flight has the same limitation.  Say it takes 2 kg of fuel to lift 1 kg of fuel. (Don't know the exact numbers, but I've heard 2-1 works.)  This is why on orbit refueling is a big step to mankind moving past Earth.
 
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Offline coppercone2

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #94 on: March 28, 2024, 02:40:50 am »
this is why the nostromo had a self destruct on it

I wonder if these ships will be robotic one day (or have a escape helicopter) and have a rapid scuttle command to sink them to save lives.
 

Offline AlfBaz

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #95 on: March 28, 2024, 02:40:57 am »
It's been 20 plus years since I worked on ships that came into our local port so treat this info with a grain of salt.
I have worked on, maintained and fault found all of the gear mentioned below

Most large vessels have three main alternators driven by 3 separate diesel engines. Each alternator is somewhere in the vicinity of 600kW and up and run on heavy fuel oil, the same as the main engine.

This fuel at room temperature is a tar like substance and is heated to decrease its viscosity. It is then run through centrifugal separators to get rid of impurities prior to being fed to the engines

Under normal electrical load conditions only one alternator powers the main switchboard.

There are 2 methods of bringing a second or third main alternator on line. Automatically or manually. Both methods are the same just controlled by hand or actuators.
The alternator to be brought on line is started, its governor is adjusted to bring the frequency of the alternators’ output up as close as possible as the one already on line.
At this stage, fine adjustments are made to the speed to get the three phases in sync using either the three old school synchro lights or simply an analogue meter whose 12 o'clock position corresponds to phase alignment.

As the needle or lights come around slowly to the synchronized position it is connected to the main bus.

At this stage, depending on what you want to do the load sharing is adjusted by increasing or decreasing the governors whilst at the same time watching the frequency.
For example if you want to bring an extra alternator online you would start the diesel, synchronize and connect it to the bus. Once connected you increase the governor speed which has the effect of increasing that generators load and decreasing the load on the existing one. If the line frequency starts getting too high then you decrease the speed of the alternator with the most load.
Most of the ships at that time didn’t have autonomous load sharing, we did start to introduce these systems onto some vessels but that’s another story.

Ships that had bow thrusters needed two geny’s on line. Namely to handle the start up current but consequently as a safety measure, should one trip off.

All of the bow thrusters I had seen had variable pitch propellers and had to be at zero pitch before they could be started. Some were DOL others employed old school resistance starters with the latter method having massive inline resistance starters or slipring motors with resistors in their rotor circuits shorted out in stages

They all have an emergency alternator that runs on normal diesel fuel that have a substantially lower kW rating and start automatically when power loss is detected on the main buss. These were also air start.

When the emergency alternator is running only a small subset of essential equipment is powered and the main generators can't be switched onto the main bus until the emergency geny is ofline

In addition to emergency AC there are large banks of single cell batteries stacked up to create an emergency 24VDC supply for navigation, radios etc.

Some vessels had more than one bank for DC supplie for other various systems. One example of this was for a vessel that had three internal gantry cranes used to move and store large 30 tonne slabs of steel with large electro magnets. A large bank of AGM batteries making up 110VDC were used in the event of loss of power to ensure a slab wouldn’t detach.

In the steering flat where the top of the rudder comes into the ship, there would be a series of hydraulic rams actuated by a large pump and indeed had a backup. The port and starboard pumps. In fact there is very little equipment on a ship that doesn’t have 2 of everything.

If that vessel had a bow thruster it would explain why all the deck lights turned on and off as with the emergency geny, only a few would have turned on but the bow thruster certainly could NOT be run off of it so they would have been attempting to put the main genys back online which presumably tripped when attempting to restart the bow thruster.

Having worked on many overseas ships they were often poorly maintained with a lot of safety stuff spragged out. Many times when surveyors were called onboard to inspect dodgy vessels, they would be laid up and barred from going to sea until rudimentary safety gear was repaired.

Speculating here, but if they were attempting to restart the bow thruster any number of issues would certainly cause the generators to trip off

edit: typo bow thruster can not be run from emergency generator
« Last Edit: March 28, 2024, 03:37:53 am by AlfBaz »
 
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Offline NiHaoMike

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #96 on: March 28, 2024, 04:51:38 am »
Given all the difficulty of having to match phases, wouldn't HVDC make more sense nowadays? And/or just stick to hydraulics for the big mechanical stuff?
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Offline AlfBaz

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #97 on: March 28, 2024, 06:00:25 am »
Most ships don't carry an electrician any more let alone EE's. So having complex systems out in the middle of the ocean needs simpler systems which facilitate farming style bodges.

I recollect one vessel coming into port where the ctrl system wouldn't, for some reason or another, allow some motor contactor to energize. I opened the front enclosure door and a lump of timber fell out as they'd jammed it in there to keep some pump motor running till they got to shore
 

Offline tooki

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #98 on: March 28, 2024, 07:44:41 am »
The police stopped the traffic.  This is well documented.  (https://www.foxnews.com/video/6349808520112).  Also there are no toll booths on this bridge (https://www.google.com/maps/place/Francis+Scott+Key+Bridge,+Maryland/@39.2298883,-76.5108951,319m/data=!3m1!1e3!4m6!3m5!1s0x89c80052ddeb3cad:0xf3fb8c8f100a3e9e!8m2!3d39.2323329!4d-76.5063164!16zL20vMDR2Njgw!5m1!1e4?entry=ttu)
I don’t do Fox News, sorry.

The various sources I saw didn’t specify exactly who was actually by the bridge directing traffic, but the construction company had stated they had traffic control staff there.


As for the toll plaza: hah, serves me right for using, um, another map app! (See attached screenshot.) Well that and the fact that I haven’t driven through there in probably a decade at least.
 

Offline tooki

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #99 on: March 28, 2024, 07:49:21 am »
At least it's not on fire.
Yet/so-far.
Why would you expect this to happen, given that no indications so far point towards anything even distantly fire-related. The Dali is now at rest, and ships at rest don’t normally just burst into flame.

The two sources of smoke initially reported by some have since been explained: the black smoke is from the engines, and the “smoke” at the point of impact is concrete dust, isn’t it?
 

Offline SeanB

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #100 on: March 28, 2024, 08:03:18 am »
Also to point out that those shipboard lights are high pressure sodium lights, which take 3 minutes to restrike when the power is interrupted. Cheap iron core and superimposed pulse starters will not strike a hot tube, until it has cooled down a little, when it will restrike, in about 3 minutes. I would also say the ship owners would also not buy dual tube lamps, where they have 2 arc tubes in parallel in the glass envelope, and which will, if there is a single power dip, have the other tube light up and run, as these cost double the price of the cheap Chinese Ya Ming lamps they likely buy by the case lot. The lights going out is a good indication of power loss, but the relight shows the hot restrike time, and they all coming on nearly at the same time says they were all from the same batch, and all had similar running hours on them, as the restrike time varies greatly with age, and from batch to batch. The only way to have hot restrike is to buy more expensive ballasts that can provide the 5kV plus needed to strike the tube, which needs the wiring to be insulated to the socket, and the socket to be rated for 5kV without flashing over, plus the tubes need a different E40 base design with a wider glass insulator.

No LED lights, the power supplies fail badly, even those designed for rough service use, and do not mix well with salt water ingress, while the magnetic will carry on till the core rots away. Also easy to relamp, as all you need to carry up in a small sling bag is a spare lamp, a new ignitor, a can of WD40 for the rusted fasteners, and some pliers and screwdrivers to open the fixture, which mostly use simple spring clips to allow tool less lamp changes. LED you have to use a rope and pulley to first lower the old one down, and then pull the new one up, and need 2 people up there, and 2 on deck, to do this. Lamp just needs one person and possibly a deck watcher for the crew of 3, doing 3 at a time in an area. Plus also 5 minutes per lamp, excluding the climb, and power does not have to be cut either.
 
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Offline Someone

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #101 on: March 28, 2024, 08:42:11 am »
At least it's not on fire.
Yet/so-far.
Why would you expect this to happen, given that no indications so far point towards anything even distantly fire-related. The Dali is now at rest, and ships at rest don’t normally just burst into flame.

The two sources of smoke initially reported by some have since been explained: the black smoke is from the engines, and the “smoke” at the point of impact is concrete dust, isn’t it?
Mostly in jest, but grounded ships have subsequently caught fire in the past so its not implausible.
 

Offline Circlotron

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #102 on: March 28, 2024, 11:50:08 am »
And a fraction of the size of the biggest ships today, which currently top out at 24,000 TEU!
That's twelve thousand large truck's worth! Yowsers!
 
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Offline floobydust

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #103 on: March 28, 2024, 06:45:15 pm »
At least it's not on fire.
Yet/so-far.
Why would you expect this to happen, given that no indications so far point towards anything even distantly fire-related. The Dali is now at rest, and ships at rest don’t normally just burst into flame.

The two sources of smoke initially reported by some have since been explained: the black smoke is from the engines, and the “smoke” at the point of impact is concrete dust, isn’t it?

Cargo manifest shows 56 containers of hazardous (764 tons) mostly corrosives, flammables, "Class 9 including lithium-ion batteries" according to the NTSB Media Briefing 2.
Containers are flattened, crushed. Some in the water, some are leaking. There's around 4,700 on the ship.

It's not a static situation, tides up and down and things have to be moved, torched cut as they clean up the mess.
I would say there is a fire risk- but putting it out is the impossibility if one starts. The bow has a huge hole in it.
 

Offline tooki

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #104 on: March 28, 2024, 06:57:44 pm »
At least it's not on fire.
Yet/so-far.
Why would you expect this to happen, given that no indications so far point towards anything even distantly fire-related. The Dali is now at rest, and ships at rest don’t normally just burst into flame.

The two sources of smoke initially reported by some have since been explained: the black smoke is from the engines, and the “smoke” at the point of impact is concrete dust, isn’t it?
Mostly in jest, but grounded ships have subsequently caught fire in the past so its not implausible.
I said ships do not normally catch fire, not that it's impossible.

And it's not grounded, mind you. The ship is afloat.
 

Offline tooki

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #105 on: March 28, 2024, 06:58:53 pm »
Cargo manifest shows 56 containers of hazardous (764 tons) mostly corrosives, flammables, "Class 9 including lithium-ion batteries" according to the NTSB Media Briefing 2.
Containers are flattened, crushed. Some in the water, some are leaking. There's around 4,700 on the ship.

It's not a static situation, tides up and down and things have to be moved, torched cut as they clean up the mess.
I would say there is a fire risk- but putting it out is the impossibility if one starts. The bow has a huge hole in it.
Definitely not impossible. But no reason to assume it's a likely outcome.
 

Offline coppercone2

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #106 on: March 28, 2024, 07:08:37 pm »
a container full of massagers might turn on and cause the entire situation to shake apart
 
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Offline Sal Ammoniac

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #107 on: March 28, 2024, 07:24:48 pm »
This fuel at room temperature is a tar like substance and is heated to decrease its viscosity. It is then run through centrifugal separators to get rid of impurities prior to being fed to the engines

One theory that I've seen, that sounds plausible, is that contaminated fuel clogged the fuel filters for the generators, causing the generators to stop. Perhaps the ship didn't have centrifugal separators, or the separators didn't filter out enough impurities to prevent clogging the filters.

The bunker oil used as fuel on ships like this one is the dregs of the petroleum refining process and often contains gunk that may be problematic.

All of this should be easy enough to figure out as the ship is still intact and presumably there's data logging that will point to the cause of the problem.
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Offline tooki

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #108 on: March 28, 2024, 07:44:26 pm »
All of this should be easy enough to figure out as the ship is still intact and presumably there's data logging that will point to the cause of the problem.
Yep. The NTSB has already taken the data recorder. However, we may end up disappointed with what it contains, or rather doesn't.

This is what the NYT reported:
Quote
Jennifer Homendy, the N.T.S.B. chair, says the agency has long wanted more data to be recorded on ships’ voyage data recorders. She described the apparatus as recording only basic data, far less than is the case with the recording devices — or “black boxes” — on commercial airplanes.

N.T.S.B. officials said the voyage data recorder on the ship was a newer model, with additional features, but is still “very basic” compared to what would be on a commercial airplane. It does not, for example, record power distribution data, they said. However, it does record the ship's location, rudder commands and audio.
 

Online tom66Topic starter

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #109 on: March 28, 2024, 09:14:06 pm »
It should be easy enough to examine parts of the engines, generators, fuel and fuel system to determine the likely fault.  Chances are, if they powered the ship up in this configuration they'd be able to replicate the fault too, if it's related to a problem that exists there rather than crew misoperation.

It sounds like from another NTSB report that the data recorders are only operational when the main ship power is running, so they likely only recorded data when things were operating correctly.  The audio recorders, however, do operate off backup batteries, and so they've retrieved the audio from the ship's bridge for the duration of the incident.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #110 on: March 28, 2024, 10:55:05 pm »
At least it's not on fire.
Yet/so-far.
Why would you expect this to happen, given that no indications so far point towards anything even distantly fire-related. The Dali is now at rest, and ships at rest don’t normally just burst into flame.

The two sources of smoke initially reported by some have since been explained: the black smoke is from the engines, and the “smoke” at the point of impact is concrete dust, isn’t it?
Mostly in jest, but grounded ships have subsequently caught fire in the past so its not implausible.
I said ships do not normally catch fire, not that it's impossible.

And it's not grounded, mind you. The ship is afloat.
Equally I'm not saying it will catch on fire in the future for certain. yet/so-far both leave either possibility for the future and literally mean "up to the current time".

As to grounded, if it cant move as its tangled in things sitting on the riverbed, that mass/agglomeration of which the ship is a part is grounded.
Wikipedia references bringing the goods:
https://maritime-executive.com/article/bridge-s-weight-is-pinning-container-ship-dali-to-the-bottom
Quote
In a reversal of the usual order for a major marine salvage operation, the U.S. Army Corps of Engineers (USACE) and its contractors will make the first big move in getting the wrecked container ship Dali out of Baltimore's ship channel.

Dali's bow is technically aground in the channel, said Vice Adm. Peter Gautier at a press conference Wednesday, because of the vast weight of the steel bridge span resting on top. The ship is pinned to the bottom and cannot move.
« Last Edit: March 28, 2024, 10:59:11 pm by Someone »
 

Offline Andy Chee

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #111 on: March 28, 2024, 11:40:36 pm »
And it's not grounded, mind you. The ship is afloat.
Not with the weight of a broken bridge span sitting on the deck of the bow!

I’ll be fascinated with the salvage operation. Much like the refloating of Costa Concordia, they’ll have to be careful about weight and buoyancy shifts.
 

Offline coppercone2

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #112 on: March 29, 2024, 01:17:22 am »
let people claim containers as salvage and it will be gone in 3 days


However the value of a good failure analysis could benefit us for the next 100 years if they figure out every detail and determine how to make improvements
 

Offline Andy Chee

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #113 on: March 29, 2024, 01:49:10 am »
Once enough debris has been manually cleared from the ship’s bow, the ship refloated and towed away, the remaining bridge span elements, both above and below water, will probably be broken down into smaller pieces by demolition explosives.

The bridge is way too big to cut apart with plasma torches or oxygen lances.

The ship itself is also probably destined for scrap metal yard.
« Last Edit: March 29, 2024, 01:51:23 am by Andy Chee »
 

Offline floobydust

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #114 on: March 29, 2024, 01:54:02 am »
Keep the ship for collateral - some 1851 law which was cited by the Titanic’s owner in a Supreme Court case 1912, could limit the payout. Titanic law could help ship owner limit liability in Baltimore bridge collapse

Estimates are $2B to repair/replace the bridge, $0.1B to free the ship and clean up the mess. Biden is talking like the Feds will give the money, but I have to ask why the US taxpayer is ultimately on the hook, as well as the many years of cranked up toll pricing we know will result. OUCH.
 

Offline Andy Chee

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #115 on: March 29, 2024, 02:06:07 am »
Keep the ship for collateral - some 1851 law which was cited by the Titanic’s owner in a Supreme Court case 1912, could limit the payout. Titanic law could help ship owner limit liability in Baltimore bridge collapse

Estimates are $2B to repair/replace the bridge, $0.1B to free the ship and clean up the mess. Biden is talking like the Feds will give the money, but I have to ask why the US taxpayer is ultimately on the hook, as well as the many years of cranked up toll pricing we know will result. OUCH.

Recouping the costs from the “at fault” parties, will probably take a long time in courts, longer than if the US government financed the rebuilding from the start.

The US government can always recoup the costs later.
 

Offline xrunner

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #116 on: March 29, 2024, 02:06:26 am »
Oh yea Money Money Money (I'm humming the song from Dark Side of the Moon in my head at the moment). Of course we have lessons learned from the collapsed bridge, so they'll design the new one to withstand such a crash better. Maybe more lanes? How about restaurants and shopping areas at the entrances. The list goes on ...  :-DD
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Offline coppercone2

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #117 on: March 29, 2024, 02:45:24 am »
Oh yea Money Money Money (I'm humming the song from Dark Side of the Moon in my head at the moment). Of course we have lessons learned from the collapsed bridge, so they'll design the new one to withstand such a crash better. Maybe more lanes? How about restaurants and shopping areas at the entrances. The list goes on ...  :-DD

I think you should put them on the bridge. Like the original london bridge.

I think you are going here with your idea.


You could buy all sorts of services on it. From the late seventeenth century there was a greater variety of trades, including metalworkers such as pinmakers and needle makers, sellers of durable goods such as trunks and brushes, booksellers and stationers.[18]


How about a drive through chapel?
« Last Edit: March 29, 2024, 02:47:46 am by coppercone2 »
 

Online SiliconWizard

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #118 on: March 29, 2024, 03:02:11 am »
let people claim containers as salvage and it will be gone in 3 days

I know it's just tongue-in-cheek, but just for the sake of the idea, how would people salvage all this in 3 days right in the middle of the river with no bridge?
 

Offline themadhippy

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #119 on: March 29, 2024, 03:40:52 am »
Quote
how would people salvage all this in 3 days right in the middle of the river with no bridge
canoes
 

Offline floobydust

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #120 on: March 29, 2024, 03:58:36 am »
Given $xx million to get this ship out of the way, how are we doing it? FAST

Use Thug Technology® - wait for high tide, maybe a Supermoon - startup the ship's engine and nail it in reverse!
Use TNT and blow up that pier!
I could borrow my uncle's tugboat, maybe call up his friends and get their tugs pushin' too.

Remember the Suez Canal incident March 2021? Ever Given ran aground. It's over 2x GT as big as the MV Dali (but similar engine power, odd). Call up SMIT Salvage has a huge crane and tugs. Bloomberg story

The Francis Scott Key bridge also got nailed in 1980 by (smaller) container ship named the Blue Nagoya. Good to know nothing was changed.
 

Online SiliconWizard

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #121 on: March 29, 2024, 04:10:59 am »
Quote
how would people salvage all this in 3 days right in the middle of the river with no bridge
canoes

Yes. ;D
(Just for some figures, a 400m container ship holds an average of 20,000 TEU ( https://en.wikipedia.org/wiki/Twenty-foot_equivalent_unit ), it's hard to give an equivalent weight of course, but it's usually about 20T per TEU.
So, that's about 400,000T for the whole ship. And, of course, in containers piled up on several layers.
All that in 3 days on some canoes. :-DD )
 

Offline mfro

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #122 on: March 29, 2024, 07:17:05 am »
Stick a $10000 tag on each container and they will be gone by tomorrow.
Beethoven wrote his first symphony in C.
 

Offline coppercone2

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #123 on: March 29, 2024, 08:06:40 am »
I think they would form a fleet of various boats from all over the place in american east coast to take it on anything they can
 

Offline Jeroen3

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #124 on: March 29, 2024, 08:21:12 am »
Given all the difficulty of having to match phases, wouldn't HVDC make more sense nowadays? And/or just stick to hydraulics for the big mechanical stuff?
Yes and no. Matching phases is easy, we're doing for decades. The gear is there, you can buy DEIF, Woodward, Deep Sea controllers for it. Standard gear. DC is not standard. It requires inverters, and those are complicated and dangerous. They require complex control theory and software. Where you can manually keep spinning copper in check if you have to.

However it is attempted. DC busses or having a few drives on DC bus is attempted at some ships. I know of a large ferry and some youghts but inverters do not play not nice with good old spinning copper and iron. Plagued with problems and breakdowns.
Inverters can do things generators cannot keep up with, not engine wise, not control wise and not due to reactances, complicated physiscs.
 

Online SiliconWizard

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #125 on: March 29, 2024, 09:01:49 am »
I think they would form a fleet of various boats from all over the place in american east coast to take it on anything they can

There are things that are physically difficult. Various boards all over the place? That would be a major safety hazard, that's just insane. :-DD
And you can't lift those containers like that, they are all tightly placed next to one another and on top of one another. That needs major means to do it effectively and safely.
 

Online SiliconWizard

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #126 on: March 29, 2024, 09:04:11 am »
Speaking of figures, if I didn't mess up my calculations, at the speed the ship was estimated to move when it hit the pillar and with its estimated mass, the energy must have been something the equivalent of the explosion of between 500kg and 1t TNT. Just to get an idea.
 
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #127 on: March 29, 2024, 10:17:55 am »
Sunrise in Baltimore: 6:55 AM:

Quote
Oh, say, can you see
By the dawn's early light
What so proudly we hail'd
At the twilight's last gleaming?

Whose bright containers shined
Through the perilous night
O'er the river's banks we watched
And the Dali was still there.

Inspired by FSK and quoted in part.
 

Offline xrunner

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #128 on: March 29, 2024, 10:58:46 am »
Quote
how would people salvage all this in 3 days right in the middle of the river with no bridge
canoes

Didn't the ancient Egyptians move multi-ton obelisks on simple wooden boats?  :-DD
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Online langwadt

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #129 on: March 29, 2024, 11:31:30 am »
This fuel at room temperature is a tar like substance and is heated to decrease its viscosity. It is then run through centrifugal separators to get rid of impurities prior to being fed to the engines

One theory that I've seen, that sounds plausible, is that contaminated fuel clogged the fuel filters for the generators, causing the generators to stop. Perhaps the ship didn't have centrifugal separators, or the separators didn't filter out enough impurities to prevent clogging the filters.

The bunker oil used as fuel on ships like this one is the dregs of the petroleum refining process and often contains gunk that may be problematic.

All of this should be easy enough to figure out as the ship is still intact and presumably there's data logging that will point to the cause of the problem.

coastal areas and ports are sulfur emission controlled areas, so there they run bunker A which is basically diesel 

 

Offline switchabl

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #130 on: March 29, 2024, 12:14:41 pm »
Keep the ship for collateral - some 1851 law which was cited by the Titanic’s owner in a Supreme Court case 1912, could limit the payout. Titanic law could help ship owner limit liability in Baltimore bridge collapse

Estimates are $2B to repair/replace the bridge, $0.1B to free the ship and clean up the mess. Biden is talking like the Feds will give the money, but I have to ask why the US taxpayer is ultimately on the hook, as well as the many years of cranked up toll pricing we know will result. OUCH.

The article makes it sound a bit like it is some loophole in an old, forgotten law. But in fact the principle of limited liability has been a central element of maritime codes internationally for centuries and it comes up in almost all major shipping accidents.

Now, many people do think that this doesn't really make sense anymore in a world where LLCs and huge insurance companies exist and shipping isn't nearly as dangerous as it used to be. But any attempt to change this unilaterally might prove hard to enforce. E.g. the owner of the MV Dali is based in Singapore which is a member of the International Convention on Limitation of Liability for Maritime Claims.
 

Offline Sal Ammoniac

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #131 on: March 29, 2024, 03:00:22 pm »
coastal areas and ports are sulfur emission controlled areas, so there they run bunker A which is basically diesel 

Sometimes they run cleaner fuel when in port and switch to the dirty stuff when at sea.

Even the lowest grade bunker fuel is lower in sulfur than it used to be. In fact, that change has contributed to global warming because higher sulfur emissions tended to mitigate warming.
"That's not even wrong" -- Wolfgang Pauli
 

Online langwadt

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #132 on: March 29, 2024, 03:11:42 pm »
coastal areas and ports are sulfur emission controlled areas, so there they run bunker A which is basically diesel 

Sometimes they run cleaner fuel when in port and switch to the dirty stuff when at sea.

yep, and if they are going to shut down the engines. Don't want things to cool down with the thick fuel that needs to be hot   

Even the lowest grade bunker fuel is lower in sulfur than it used to be. In fact, that change has contributed to global warming because higher sulfur emissions tended to mitigate warming.

yes, the global limit was lowered to 0.5% from (afair) 3.5% in 2020, I think in ports and coastal areas it is ~0.1%

 

Offline coppice

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #133 on: March 29, 2024, 03:16:18 pm »
Even the lowest grade bunker fuel is lower in sulfur than it used to be. In fact, that change has contributed to global warming because higher sulfur emissions tended to mitigate warming.
The response to this seems to be that we now need to throw more crap into the atmosphere to replace the crap we've just removed. Welcome to clown world.
 

Offline xrunner

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #134 on: March 29, 2024, 04:27:50 pm »
The largest crane on the Eastern seabord has arrived at the bridge. That may well be, but it doesn't seem large next to the wreckage.  :o
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Offline delfinom

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #135 on: March 29, 2024, 05:49:06 pm »
The largest crane on the Eastern seabord has arrived at the bridge. That may well be, but it doesn't seem large next to the wreckage.  :o

* Largest water borne crane the army corps of engineers has access to


Also the photo is not even correct, they took a photo of another crane that got moved closer to the wreck.

This is the crane that's called in:
https://www.donjon.com/ches1000.htm
« Last Edit: March 29, 2024, 05:54:28 pm by delfinom »
 

Offline Sal Ammoniac

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #136 on: March 29, 2024, 06:14:31 pm »
That crane looks precarious. It's hard enough working with big cranes near the limit of their load capacity on solid ground--doing it on a floating barge adds another element of difficulty.
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Offline floobydust

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #137 on: March 29, 2024, 07:35:02 pm »
Is this an example of decaying infrastructure or misplaced pride?

That crane barge built in 1972, max. 1,000 short tons (within 63ft), Donjon's stuff is all very old but with upgrades apparently.
It looks not enough to deal with the mangled steel trusses, and having to cut it up into nice little pieces will take a long time.
Just phone up a professional salvage company that has real cranes and foot the bill. The port needs to be open ASAP.

"U.S. Army Corps of Engineers (USACE) is deploying more than 1,100 personnel to Baltimore..."
It's going to be impressive, they don't mess around- but you still need good tools for the job.
 

Offline mariush

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #138 on: March 29, 2024, 07:51:39 pm »
I was wondering how feasible would be inflate some thick things with air or something and tie the to the metal of the bridge and then cut small segments of that bridge and drag the segments to the river sides while they float.

Maybe even something like filling shipping containers with ping pong balls or something and welding them shut... cheap flotation devices with mounting points at the corners to attach to the bridge.

I'm thinking the surface of the bridge would be the hardest to lift out the water and remove it, I imagine they'd have to cut strips and lift it with the crane.

I guess river's too deep for a boat like this to work :



 

Offline coppercone2

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #139 on: March 29, 2024, 07:56:22 pm »
Is this an example of decaying infrastructure or misplaced pride?

That crane barge built in 1972, max. 1,000 short tons (within 63ft), Donjon's stuff is all very old but with upgrades apparently.
It looks not enough to deal with the mangled steel trusses, and having to cut it up into nice little pieces will take a long time.
Just phone up a professional salvage company that has real cranes and foot the bill. The port needs to be open ASAP.

"U.S. Army Corps of Engineers (USACE) is deploying more than 1,100 personnel to Baltimore..."
It's going to be impressive, they don't mess around- but you still need good tools for the job.

they need to make better boats because fuck the cost going on the tax payer. You can probobly make a better bridge but someone is just gonna make a bigger boat. Its way cheaper to make the boat and it effects way less people if they improve the boat rather then improving the bridge.

Why should we have to build crazy bridges, when there is a over seas non American manufacturer that probably caused this problem by putting copper clad wire in a generator to keep his costs down?


Like we are gonna end up eating off brand ramen to protect the right of Marsk to use alibaba inverters and crap like that. I don't think the infrastructure is failing.
« Last Edit: March 29, 2024, 07:59:47 pm by coppercone2 »
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #140 on: March 29, 2024, 08:16:22 pm »
Is this an example of decaying infrastructure or misplaced pride?

That crane barge built in 1972, max. 1,000 short tons (within 63ft), Donjon's stuff is all very old but with upgrades apparently.
It looks not enough to deal with the mangled steel trusses, and having to cut it up into nice little pieces will take a long time.
Just phone up a professional salvage company that has real cranes and foot the bill. The port needs to be open ASAP.

"U.S. Army Corps of Engineers (USACE) is deploying more than 1,100 personnel to Baltimore..."
It's going to be impressive, they don't mess around- but you still need good tools for the job.

they need to make better boats because fuck the cost going on the tax payer. You can probobly make a better bridge but someone is just gonna make a bigger boat. Its way cheaper to make the boat and it effects way less people if they improve the boat rather then improving the bridge.

Why should we have to build crazy bridges, when there is a over seas non American manufacturer that probably caused this problem by putting copper clad wire in a generator to keep his costs down?


Like we are gonna end up eating off brand ramen to protect the right of Marsk to use alibaba inverters and crap like that. I don't think the infrastructure is failing.

what a weird nonsensical rant..
 
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Offline coppercone2

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #141 on: March 29, 2024, 08:22:29 pm »
whats decaying about the infrastructure? It was a fine bridge. Probably would have passed inspection for 50 years more. It is the ship that was having problems even by its service history. A boeingesque problem?
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #142 on: March 29, 2024, 08:41:07 pm »
Worse than Boeing, IMO, although (usually) less of a problem as there are no passengers.
The reliability and maintenance of those cargo ships are disastrous, from what I've heard.
 

Offline David Hess

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #143 on: March 29, 2024, 08:49:38 pm »
whats decaying about the infrastructure? It was a fine bridge. Probably would have passed inspection for 50 years more. It is the ship that was having problems even by its service history. A boeingesque problem?

The ship has been in service for a while, so a maintenance problem is more likely than a design or manufacturing problem.  It could have been contaminated fuel so we will have to wait for the investigation and report.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #144 on: March 29, 2024, 10:05:01 pm »
what a weird nonsensical rant..
Especially when pretty much everybody agrees America's infrastructure is in bad state of decay and in serious need of update, repair, improvement and maintenance.

A search for America, infrastructure, decay brings up dozens of pages, including the White House.

https://www.businessinsider.com/asce-gives-us-infrastructure-a-d-2017-3
https://www.csis.org/analysis/united-states-broken-infrastructure-national-security-threat
https://www.whitehouse.gov/cea/written-materials/2021/11/15/the-time-is-now-to-modernize-u-s-infrastructure/

And, in any case, the prevention of accidents, in general, is a multitude of layers, of redundancy. 

That bridge today would be built with a breakwater and other better measures that it had when it was built fifty years ago.

Accidents happen. They happen in American built ships. They happen in American navy ships. They happen.

Blaming the whole thing on a foreign built component is misplaced.

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Online tom66Topic starter

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #145 on: March 29, 2024, 10:48:38 pm »
Given the last disaster of similar scale in the USA was almost 50 years ago, it could be argued that a one-in-50 year event is not worth spending billions of dollars on (across all possible bridges on entry to ports in the USA).

Whilst tragic that six lives were lost,  it is clear that the port authority and bridge operator had reasonable mitigation for this type of disaster by being able to close the bridge to traffic quickly.  The cost is mostly economic, and even if it costs $2 billion to rebuild this bridge, it would probably not be worth spending, for instance, a further $2 billion on reinforcing remaining bridges.

I would like to see maritime law changed to make the insurers liable for these costs, though.  It's not okay that the federal government has to pick up the tab for incompetent maintenance, or contaminated fuel.

Edit: corrected amount, brain fart
« Last Edit: March 29, 2024, 10:57:20 pm by tom66 »
 
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Online soldar

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #146 on: March 29, 2024, 11:01:26 pm »
I would like to see maritime law changed to make the insurers liable for these costs, though.  It's not okay that the federal government has to pick up the tab for incompetent maintenance, or contaminated fuel.
Where do you get the idea that the insurers are not liable?
Quote
https://edition.cnn.com/2024/03/28/business/who-ends-upholdingthebagfor-the-baltimore-bridge-collapse/index.html

Insurers footing the bill

The Dali ship is owned by Grace Ocean Private, a Singapore-based company, and insured by the Britannia Protection and Indemnity Club.

Britannia is one of the dozen marine insurance member clubs under the International Group of P&I Clubs, a consortium that provides marine liability coverage for 90% of ocean freight and pools liability claims among members. (The International Group of P&I Clubs did not respond to CNN’s request for comment.)

These insurance companies are backed by insurance companies of their own – a type of business known as a reinsurer.

Around 80 different reinsurers provide around $3 billion in coverage to the Dali’s insurers, according to Moody’s analyst Brendan Holmes. Since the losses will be spread across so many insurers, it’s unlikely to bankrupt any of the companies or cause a major bump in insurance prices, he said.
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Online tom66Topic starter

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #147 on: March 29, 2024, 11:19:44 pm »
I would like to see maritime law changed to make the insurers liable for these costs, though.  It's not okay that the federal government has to pick up the tab for incompetent maintenance, or contaminated fuel.
Where do you get the idea that the insurers are not liable?

The post above by @floobydust suggests they might be on the hook for a maximum of the ship's value + cost of cargo transport.  So probably north of $100mn, but well short of the cost of one replacement bridge.
 

Offline floobydust

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #148 on: March 29, 2024, 11:49:14 pm »
whats decaying about the infrastructure? It was a fine bridge. Probably would have passed inspection for 50 years more. It is the ship that was having problems even by its service history. A boeingesque problem?

I meant the infrastructure to deal with modern shipping accidents - such as newer, VLCC tankers, big container ships, scuttling or on fire etc.
It's all fine letting these ships in/out of ports and on your waters, but at the same time you need to invest in the equipment to deal with their calamity, and not be caught with your pants down.
Coast Guard, U.S. Army Corps of Engineers (USACE) etc. doesn't have the equipment and it looks like neither do American salvage companies. We'll see how that crane barge from New Jersey does.

edit: It's the largest crane in the Eastern Seaboard.
edit 2: I was right, nobody makes a crane like this for general purpose unless...
"The crane originally was built as the Sun 800 in 1972 to help construct the Hughes Glomar Explorer, a deep-sea vessel used by the CIA in a secret mission called "Project AZORIAN" to recover a Soviet nuclear submarine that sank in the Pacific Ocean during the Cold War {1968}, according to the Engineering News-Record."
« Last Edit: March 30, 2024, 03:33:17 am by floobydust »
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #149 on: March 30, 2024, 12:18:35 am »
I would like to see maritime law changed to make the insurers liable for these costs, though.  It's not okay that the federal government has to pick up the tab for incompetent maintenance, or contaminated fuel.
Where do you get the idea that the insurers are not liable?

The post above by @floobydust suggests they might be on the hook for a maximum of the ship's value + cost of cargo transport.  So probably north of $100mn, but well short of the cost of one replacement bridge.
Regardless of the liability, I would advise not legislating in the heat of the moment and pondering things very carefully. Legislating too quick makes for bad laws.

All countries, including the USA, have many ways of limiting liability because it is considered to result in a benefit to society in the big picture. Limited liability corporations, bankruptcy laws, etc. might seem unjust in specific cases but they benefit society as a whole.

Governments already pay for infrastructure out of taxes because it results in economic activity and development and well being.

If the government required every business to have unlimited insurance coverage then many businesses would have to shut down because it would not be affordable. 

I do not know but maybe if the USA required too much insurance or other requirements for ships and other forms of freight then that would result in much higher shipping costs or even in some ships or companies just refusing to go there.

It may well be that the USA considers the cost of rebuilding a bridge every few years more affordable than putting very onerous requirements on ships.

Legislating in the heat of the aftermath often makes bad law and has unwanted consequences.

Laws have to be considered and crafted very carefully and even then they often backfire.

The Jones Act requires vessels transporting freight within American ports to be American built and crewed. The ostensible purpose was to protect the American shipbuilding industry. In fact it totally backfired.

https://www.cato.org/publications/policy-analysis/jones-act-burden-america-can-no-longer-bear

I would advise to tread slowly and carefully and consider changes with great care.
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Offline JustMeHere

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #150 on: March 31, 2024, 04:00:16 am »
Check out this video on how those engines work. 



So the smoke is not likely the ship being "slammed" into reverse.  You just can't do that with these engines.  You basically have to stop the engine and restart it, and that takes a long time.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #151 on: March 31, 2024, 05:32:35 am »
Some analysis:


 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #152 on: March 31, 2024, 08:05:40 am »
[..]
It may well be that the USA considers the cost of rebuilding a bridge every few years more affordable than putting very onerous requirements on ships.
[..]

    The monetary cost perhaps, but the loss of live (even if just minuscule when compared to car traffic) won't be very popular.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #153 on: April 01, 2024, 02:26:58 am »
Wow, the response time of the pilot on board was incredible.
30 second after losing power the first time he was calling to get the bridge closed, and it was within 2 1/2 minutes.
https://twitter.com/cfishman/status/1773733488295882896
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #154 on: April 01, 2024, 02:31:04 am »
Wow, the response time of the pilot on board was incredible.
30 second after losing power the first time he was calling to get the bridge closed, and it was within 2 1/2 minutes.
https://twitter.com/cfishman/status/1773733488295882896

afiau the only reason they actually managed to close the bridge so fast was that police was already there because of the work being done on the bridge
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #155 on: April 01, 2024, 03:16:20 am »
Wow, the response time of the pilot on board was incredible.
30 second after losing power the first time he was calling to get the bridge closed, and it was within 2 1/2 minutes.
https://twitter.com/cfishman/status/1773733488295882896

afiau the only reason they actually managed to close the bridge so fast was that police was already there because of the work being done on the bridge

Yes.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #156 on: April 01, 2024, 08:20:59 am »
This kind of accidents happen with certain regularity for one reason or another.

https://www.independent.co.uk/news/world/americas/oklahoma-highway-barge-bridge-closure-baltimore-b2521319.html

Barge hits bridge in Oklahoma just days after Baltimore tragedy

State patrol troopers closed US Highway 59 about 1:25 pm after receiving word of the incident and diverted traffic from the area

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Offline AlfBaz

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #157 on: April 02, 2024, 09:25:35 pm »
This fuel at room temperature is a tar like substance and is heated to decrease its viscosity. It is then run through centrifugal separators to get rid of impurities prior to being fed to the engines

One theory that I've seen, that sounds plausible, is that contaminated fuel clogged the fuel filters for the generators, causing the generators to stop. Perhaps the ship didn't have centrifugal separators, or the separators didn't filter out enough impurities to prevent clogging the filters.

The bunker oil used as fuel on ships like this one is the dregs of the petroleum refining process and often contains gunk that may be problematic.

All of this should be easy enough to figure out as the ship is still intact and presumably there's data logging that will point to the cause of the problem.

coastal areas and ports are sulfur emission controlled areas, so there they run bunker A which is basically diesel

*********************************************************

coastal areas and ports are sulfur emission controlled areas, so there they run bunker A which is basically diesel 

Sometimes they run cleaner fuel when in port and switch to the dirty stuff when at sea.

yep, and if they are going to shut down the engines. Don't want things to cool down with the thick fuel that needs to be hot   


Even the lowest grade bunker fuel is lower in sulfur than it used to be. In fact, that change has contributed to global warming because higher sulfur emissions tended to mitigate warming.

yes, the global limit was lowered to 0.5% from (afair) 3.5% in 2020, I think in ports and coastal areas it is ~0.1%

Contaminated fuel causing this issue is highly unlikely. If it were, the ship would of stayed blacked out. The fact that power was reenergised in short times indicates an electrical fault

Main engines are always stopped in port, ALWAYS

Main Engines are designed to run on heavy fuel oil (HFO) you can't change fuel on the fly and the cost of running a vessel on anything approaching diesel would be prohibitively expensive and need a completely different engine.

Then there' the matter of being able to carry the volume of any fuel other than HFO to be able to make the voyage.
The fuel oil tanks are at capacity when setting off.

If it were feasible to change the fuel type you would need the ship to drop anchor and change out major engine components.
Simply throwing a valve from one fuel to another is not what would happen you would have to clean out the cylinder liners and the scum deposits internally would require waiting for the main engine to cool down, remove heads and possibly liners and pistons and having people climb into the scrubbers to clean them out.

You have to remember that fuel ignition is caused by compressing the fuel air mixture, causing it to heat up and the fire. There is no "spark plug" that determines when it fires.
The firing point is determined by the stroke of the piston and bore diameter.
Not to mention the different operating temperatures caused by using different types of fuels. This alone would require fundamental mechanical engineering properties of the engine to change as heat exchangers would need to be different based the different heat generated from different fuels

As for who's fault this is, I would be looking at the port authority who allowed a vessel to navigate past what is an intrinsically flimsy bridge to move through this area without tug boats. Sure bow thrusters are installed to mitigate tug cost but it is electrical equipment which is prone to fail without notice and to not have a backup for this the outcome could be predicted by anyone who has the slightest idea of what hazard analysis is.

Given the power generation is at the back of the ship and bow thrusters are at the front of it and the typical length of a ship is 300-400m, voltage drop on startup is huge.
I have seen some vessels employ large transformers to increase the generated 415 3 phase voltage to 3.3kV to reduce the cable size feeding the bow thruster motors but I am not entirely sure this is standard practice.
Haven't seen any concrete evidence this vessel even has a bow thruster. If it doesn't then certainly a port authority issue for not using tug boats to manoeuvrer the ship out of the harbour.

Lets also not forget that when pilots are on board they're captaining the ship so the responsibility is on them not the master


 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #158 on: April 02, 2024, 11:33:44 pm »
This fuel at room temperature is a tar like substance and is heated to decrease its viscosity. It is then run through centrifugal separators to get rid of impurities prior to being fed to the engines

One theory that I've seen, that sounds plausible, is that contaminated fuel clogged the fuel filters for the generators, causing the generators to stop. Perhaps the ship didn't have centrifugal separators, or the separators didn't filter out enough impurities to prevent clogging the filters.

The bunker oil used as fuel on ships like this one is the dregs of the petroleum refining process and often contains gunk that may be problematic.

All of this should be easy enough to figure out as the ship is still intact and presumably there's data logging that will point to the cause of the problem.

coastal areas and ports are sulfur emission controlled areas, so there they run bunker A which is basically diesel

*********************************************************

coastal areas and ports are sulfur emission controlled areas, so there they run bunker A which is basically diesel 

Sometimes they run cleaner fuel when in port and switch to the dirty stuff when at sea.

yep, and if they are going to shut down the engines. Don't want things to cool down with the thick fuel that needs to be hot   


Even the lowest grade bunker fuel is lower in sulfur than it used to be. In fact, that change has contributed to global warming because higher sulfur emissions tended to mitigate warming.

yes, the global limit was lowered to 0.5% from (afair) 3.5% in 2020, I think in ports and coastal areas it is ~0.1%

Contaminated fuel causing this issue is highly unlikely. If it were, the ship would of stayed blacked out. The fact that power was reenergised in short times indicates an electrical fault

Main engines are always stopped in port, ALWAYS

Main Engines are designed to run on heavy fuel oil (HFO) you can't change fuel on the fly and the cost of running a vessel on anything approaching diesel would be prohibitively expensive and need a completely different engine.

Then there' the matter of being able to carry the volume of any fuel other than HFO to be able to make the voyage.
The fuel oil tanks are at capacity when setting off.
...

they a change over  to the cleaner fuel (Marine Diesel Oil) in coastal areas, changing from hot HFO to cold MDO it takes a while and of course has to be timed to use as little MDO as possible

 

Offline ZigmundRat

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #159 on: April 03, 2024, 12:39:01 am »
Some further side scan sonar imagery gives an idea of what the underwater cleanup crews are facing. Looks a mess.
https://www.msn.com/en-us/news/us/new-underwater-images-at-site-of-baltimore-s-deadly-bridge-collapse-first-vessel-uses-temp-channel/vi-BB1kWX63
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #160 on: April 03, 2024, 10:08:00 pm »
I wonder if the ship's engines work or were they damaged when the smoke was going on? It's a huge engine 3 stories 82 RPM typ.
They plan to unload that ship. "Coast Guard Rear Adm. Shannon Gilreath said... planning to remove undamaged containers off the ship but has been held up by weather..."

edit: oh, the ship is grounded, water too shallow where it sits.
« Last Edit: April 04, 2024, 04:12:54 am by floobydust »
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #161 on: April 04, 2024, 08:53:43 am »
Well, the ship has to be grounded because it left the dredged channel and so unloading the containers helps with getting the ship afloat again .. and with getting the containers on their way.
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Offline RJSV

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #162 on: April 04, 2024, 06:35:27 pm »
   I've heard cost figures, in the past (...>> 20 years ago) that one container generally has goods valued at some 1 million dollar, of course in rough terms.
Some percentage, in the case here, are going to be expensive logistical crises, especially when causing long wait times.   Consider a manufacturing line, that has to wait for container of 4 dollar parts, like a door handle for automotive factory line.

Do you wait, some weeks or months, to finally receive shipment, or, as purchasing agent, just contract out a duplicate order?   One alternative leaves (you) with an Xtra 'million' dollars worth of extra stock.i
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #163 on: April 05, 2024, 08:55:29 am »
   I've heard cost figures, in the past (...>> 20 years ago) that one container generally has goods valued at some 1 million dollar, of course in rough terms.
     I'm sure the value varies wildly.  Given that end customers pay just in the order of $2k for a container to be shipped across the Atlantic, you can expect the value to be a multiple of that.  If you're lucky, you fetch the container some multi-millionaire shipped his art collection with or the one used to smuggle cocaine, but you're more likely to fetch the one full of cheap Chinese made cloth hangers.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #164 on: April 05, 2024, 09:37:49 am »
Main engines are always stopped in port, ALWAYS

Main Engines are designed to run on heavy fuel oil (HFO) you can't change fuel on the fly and the cost of running a vessel on anything approaching diesel would be prohibitively expensive and need a completely different engine.

I'm not entirely sure I completely understand what you're arguing here, but you can't run HFO in pretty much any port or coastal zone. A changeover to DO is always performed. You're right that it isn't on the fly, it does take some time, but the procedure is pretty standard. In addition, you don't want HFO in the tubes, pumps and injectors when you shut her down. There's tracing steam on pretty much all lines but starting up the engine with HFO is always a PITA regardless.

Quote
You have to remember that fuel ignition is caused by compressing the fuel air mixture

Eh, no. You heat up and compress the air (without fuel) and then inject fuel in the hot air. These are diesel engines, not petrol.

Quote
Not to mention the different operating temperatures caused by using different types of fuels. This alone would require fundamental mechanical engineering properties of the engine to change as heat exchangers would need to be different based the different heat generated from different fuels.

Not at all. The heaters have a regulation loop based on the measured viscosity of the fuel. As a result, HFO will be heated to 120°C or so and DO to 30°C by the same machinery.

Quote
As for who's fault this is, I would be looking at the port authority who allowed a vessel to navigate past what is an intrinsically flimsy bridge to move through this area without tug boats.

Comes down to cost, obviously, but even then it is somewhay debatable if tugs would have been able to do much.

Quote
Haven't seen any concrete evidence this vessel even has a bow thruster.

Aside from every bit of documentation out there and, well, common sense?
 
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Online Kleinstein

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #165 on: April 05, 2024, 09:58:33 am »
A fuel problem is well possible to cause the engine to fail / stall. It could be as simple as an air bulble or a clogged filter that has a switch over to an alternate filter to allow cleaning on the fly.

The smoke plume is likely from restarting the engine. From the analysis (the speed of the ship did drop from that point on) this was with reverse direction, trying to slow down the vessel. This may have been the final large mistake, as this also caused the ship to turn and really get the wrong direction. With just the engine stoped, chances are they could have still passed the bridge, even with lost control over the rudder.

Using tugs may not be much safer: with such a large ship the tugs have limited control, once the ship has any useful speed. With tugs a broken line could as well cause a similar desaster if this happens at the wrong time and with some wind.
For improved safty it would be more having better backup for steering, so that a loss of control is less likely for the large vessels.
 

Offline m k

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #166 on: April 05, 2024, 12:50:09 pm »
You have to remember that fuel ignition is caused by compressing the fuel air mixture

Eh, no. You heat up and compress the air (without fuel) and then inject fuel in the hot air. These are diesel engines, not petrol.

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #167 on: April 05, 2024, 01:00:22 pm »
You have to remember that fuel ignition is caused by compressing the fuel air mixture

Eh, no. You heat up and compress the air (without fuel) and then inject fuel in the hot air. These are diesel engines, not petrol.

Sulzer?

MAN B&W
 

Offline David Hess

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #168 on: April 05, 2024, 06:03:14 pm »
The smoke plume is likely from restarting the engine. From the analysis (the speed of the ship did drop from that point on) this was with reverse direction, trying to slow down the vessel. This may have been the final large mistake, as this also caused the ship to turn and really get the wrong direction. With just the engine stoped, chances are they could have still passed the bridge, even with lost control over the rudder.

Apparently depending on the tide, there is a significant cross-current at that point in the shipping channel, so without steerage they were doomed.

Quote
Using tugs may not be much safer: with such a large ship the tugs have limited control, once the ship has any useful speed. With tugs a broken line could as well cause a similar desaster if this happens at the wrong time and with some wind.

Tugs are basically useless for handling an emergency like this, unless they want to be part of the emergency.  The bow thruster is also useless for something like this.
 
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Offline JustMeHere

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #169 on: April 05, 2024, 06:39:48 pm »
A fuel problem is well possible to cause the engine to fail / stall. It could be as simple as an air bulble or a clogged filter that has a switch over to an alternate filter to allow cleaning on the fly.

The smoke plume is likely from restarting the engine. From the analysis (the speed of the ship did drop from that point on) this was with reverse direction, trying to slow down the vessel. This may have been the final large mistake, as this also caused the ship to turn and really get the wrong direction. With just the engine stoped, chances are they could have still passed the bridge, even with lost control over the rudder.

Using tugs may not be much safer: with such a large ship the tugs have limited control, once the ship has any useful speed. With tugs a broken line could as well cause a similar desaster if this happens at the wrong time and with some wind.
For improved safty it would be more having better backup for steering, so that a loss of control is less likely for the large vessels.

Watch the engine video that has been posted.  It takes about 10 minutes to reverse a marine engine.
 

Offline JustMeHere

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #170 on: April 05, 2024, 06:45:22 pm »
Contaminated fuel causing this issue is highly unlikely. If it were, the ship would of stayed blacked out. The fact that power was reenergised in short times indicates an electrical fault

Main engines are always stopped in port, ALWAYS

Agree.  With low engine speed, electrical blowers will be feeding most of the air into the engines.

If the engine is directly connected to the shaft then there's no way it can stay at the dock with the engine running.  I guess it could, but not a good idea.
 

Offline DiodeDipShit

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #171 on: April 05, 2024, 07:44:15 pm »
Bound to happen, a very slight base, no surrounding bumpers .....
Any five fifty five will do ......
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #172 on: April 07, 2024, 01:37:26 pm »



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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #173 on: May 08, 2024, 10:24:23 am »
How Bridge Engineers Design Against Ship Collisions


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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #174 on: May 09, 2024, 12:09:16 am »
The demolition plan is to free up the cargo ship using explosives, to get the big bridge span piece off the top of the ship. The ship's crew gets to stay on board.

Regarding the Dali engine exhaust smoke, I did find this. It was a valid engine room command back in the day of steamboats in the Civil War.
Some of my projects could use one of these lol. Stop Making Smoke!
 
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #175 on: May 14, 2024, 11:08:35 pm »
NTSB Marine Investigation Preliminary Report May 14, 2024 is out, with good info on what happened (but not the cause).
I thought it strange the LV transformer TR1 primary and secondary breakers tripped at the same time. Redundant system but was brought up a bit uh odd and too late.
 
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #176 on: May 14, 2024, 11:21:54 pm »
Interesting read.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #177 on: May 14, 2024, 11:24:50 pm »
"The road maintenance inspector had been walking the length of the bridge
when the ship struck it. He ran north and made it to the nearest surviving span before
the rest of the bridge collapsed."

Hell of a story.  I'd buy a lottery ticket if I were him.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #178 on: May 15, 2024, 04:06:21 am »
I find it hard to believe it would be designed such that a single transformer would be a single point of failure for all 3 steering pumps. Had one of the steering pumps been mechanically driven from the propeller shaft (including turning at a reduced rate from the momentum of the ship after the engine shut down), might it have side scraped the bridge or missed it altogether instead of a head on collision?
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #179 on: May 15, 2024, 05:38:38 am »
The trajectory was very unfortunate. They headed up straight to the pier and avoided (by not much) the dolphin that was supposed to be a first protection. (Not sure the dolphins for this bridge would have done much for a ship this size, but who knows, maybe that would have been enough to at least change its trajectory a bit.)
 

Offline coppercone2

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #180 on: May 15, 2024, 06:42:44 am »
I find it hard to believe it would be designed such that a single transformer would be a single point of failure for all 3 steering pumps. Had one of the steering pumps been mechanically driven from the propeller shaft (including turning at a reduced rate from the momentum of the ship after the engine shut down), might it have side scraped the bridge or missed it altogether instead of a head on collision?

i swear try to get that installed at a engineering job, the only things thats gonna churn mechanically is your stomach.

you will get the randomly generated risk matrix with no defined units for the axis (I only figured out their actually related to cost and seniority level)
 

Online Ice-Tea

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #181 on: May 15, 2024, 10:03:31 am »
I find it hard to believe it would be designed such that a single transformer would be a single point of failure for all 3 steering pumps. Had one of the steering pumps been mechanically driven from the propeller shaft (including turning at a reduced rate from the momentum of the ship after the engine shut down), might it have side scraped the bridge or missed it altogether instead of a head on collision?

There is a second set of trafos and they actually managed to get those online. In addition, the EG powered up and remained active which seems to have allowed one of the steering gear pumps to remain active throughoput subsequent blackouts. Not mentioned in the report but it seems teh EG was a bit slow in coming online maybe.

Efficiency of a rudder at low speeds is poor, though, without a propeller to "force" things a bit.

Offline coppice

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #182 on: May 16, 2024, 12:27:02 pm »
I find it hard to believe it would be designed such that a single transformer would be a single point of failure for all 3 steering pumps. Had one of the steering pumps been mechanically driven from the propeller shaft (including turning at a reduced rate from the momentum of the ship after the engine shut down), might it have side scraped the bridge or missed it altogether instead of a head on collision?
People aren't very good at spot the SPOF at the best of times. When there is a cost saving they suddenly get much worse. I once worked with some FEMA (Failure mode and effect analysis) people who usually worked for the nuclear power industry, and was horrified how easily they glossed over potential problems in the systems they were looking at for us. Nobody was pressuring them to dumb down their analysis. Quite the opposite. They were tasked to be as thorough as possible. It was just their modus operandi.
 

Offline S. Petrukhin

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #183 on: May 16, 2024, 12:53:46 pm »
I would think not only about engineering problems, but also that there are people who blow up bridges and pipes in other countries...  :-//
And sorry for my English.
 
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Online Kleinstein

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #184 on: May 16, 2024, 06:10:24 pm »
Spotting tricky accident scenarios is tricky. It is quite common to have external effects (e.g. thunderstorm, extreme temperature, high wind) to stress the system an multiple points. Suddenly multiple failures at different point get more likely than normally though.

It is a bit odd design with the main motor shutting down even with a rather short interruption of the generators or just a breaker to trip, which likely can be for multiple reasons, not just overcurrent. They should have tested the effect of power interruption on stearing. It is not that there was something really unusual failing and the emergency generator was only a little late to start. To me this open the question why the design was accepted at all.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #185 on: May 16, 2024, 07:19:25 pm »
There are many non-redundant parts like the main engine, the rudder, the HV power bus, the LV power bus. Also the rudder depends on the main engine and everything depends on the electrical power buses. Seems the HVR and LVR switches that pretend redundancy were useless.
The report explains that the bow thruster is connected to the HV bus, but don't mention it later. Did DGR3 and DGR4 trip when the thruster was turned on?

Regards, Dieter
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #186 on: May 16, 2024, 10:36:31 pm »
AFAIK the bow thrusters are only effective at very low speed, like when departing from the dock. At the relatively high speed the thrusters should not be really effective. So chances are the thrusters were never started in the accident.

At least the plan shows a way to split the HV and LV bus in a left and right part to use. So they should be able to use only half the buses, but than with a fixed combination of genrators and transformer.

For me the surprising point is that the loss of the main engine caused the vessel to turn so fast that they could not counteract with the rudder driven by the emergency generator. The electrical outage was the trigger, but it looks there was more wrong than just the electric.
 

Offline S. Petrukhin

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #187 on: May 16, 2024, 11:20:37 pm »
Such massive vessel could not independently change its trajectory. Even if it is allowed to drift, it will continue to move on the same course. Keep moving in a straight line.
In order for the course to change, it is necessary to apply force. It's just ordinary physics.
The conclusion suggests itself: technical malfunctions do not matter, since there was an incorrect select for the trajectory of movement.
At least in the adjacent section of the fairway.
And sorry for my English.
 

Offline Andy Chee

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #188 on: May 17, 2024, 01:58:55 am »
Even if it is allowed to drift, it will continue to move on the same course. Keep moving in a straight line.
Water currents are often NOT straight.
 

Offline JustMeHere

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #189 on: May 17, 2024, 04:15:57 am »
Even if it is allowed to drift, it will continue to move on the same course. Keep moving in a straight line.
Water currents are often NOT straight.
Yeah.  There are two rivers involved in this.
 

Offline S. Petrukhin

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #190 on: May 17, 2024, 04:31:07 am »
Even if it is allowed to drift, it will continue to move on the same course. Keep moving in a straight line.
Water currents are often NOT straight.
A significant remark... I thought there a bay and no tangible currents.
And sorry for my English.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #191 on: May 17, 2024, 06:13:20 am »
AFAIK the bow thrusters are only effective at very low speed, like when departing from the dock. At the relatively high speed the thrusters should not be really effective. So chances are the thrusters were never started in the accident.
..
Yes exactly: They were in a harbour and slow. When space is limited, a tail rudder is of little use anyway. Before changing course by turning the ship around its vertical axis the rudder drags the ship exactly to the wrong side. I was wondering whether a 7 kW bow thruster running for some minutes could have avoided the collision or modified the impact enough to save the bridge.

Regards, Dieter
 

Online Ice-Tea

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #192 on: May 17, 2024, 06:39:10 am »
It is a bit odd design with the main motor shutting down even with a rather short interruption of the generators or just a breaker to trip, which likely can be for multiple reasons, not just overcurrent. They should have tested the effect of power interruption on stearing.

It's impossible to counter every eventuallity. If you have a blackout on a ship like this when manouvring its pretty much a given you're goig to have some egg on your face. Adding more layers of redunancy may even be counter-productive (more shit that can break). There's even an argument to be made that that already played a role here. Seems they switched to the other set of trafos the day before which then failed. If they had only had the single set of trafos they had been using before, this would not have happened.

AFAIK the bow thrusters are only effective at very low speed, like when departing from the dock. At the relatively high speed the thrusters should not be really effective. So chances are the thrusters were never started in the accident.

In addition, they run on electricity. Lots of it. Like, lots. Not something you're going to run in a blackout (obviously) or when just recovering from it.

Yes exactly: They were in a harbour and slow. When space is limited, a tail rudder is of little use anyway. Before changing course by turning the ship around its vertical axis the rudder drags the ship exactly to the wrong side. I was wondering whether a 7 kW bow thruster running for some minutes could have avoided the collision or modified the impact enough to save the bridge.

You're off by an order of magnitude. They had a 3MW bow truster.



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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #193 on: May 17, 2024, 06:54:58 am »
Even better. They could have tried, i mean they had nothing else. Probably at time they were half asleep and thought they can do nothing.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #194 on: May 17, 2024, 07:03:28 am »
Not really. Again, the bow truster needs electricity. Which they had not.

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #195 on: May 17, 2024, 07:41:55 am »
If you read the report, that's just not true. The diesels on the HV bus were running and the LV bus was operative, too, except a short period. At the time of the crash the ship had illumination.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #196 on: May 17, 2024, 07:51:37 am »
The balckout was from the brakers at the transformer tripping. From the reports the genrators were still running OK and thus the high voltage supply electricity from which the bow thruster would run still active. The problem with the bow thrusters is more that they are for really low speed, like  < 1 knot and they loose effect when going much faster. When they lost power the ship was running at some 8 knots and thus not that slow any-more.
Similar the tug boats would have to litte power to make a real difference at that speed. The habor tugs are made for low speed. So keeping the tugs would also require the ships to go slower.


Such massive vessel could not independently change its trajectory. Even if it is allowed to drift, it will continue to move on the same course. Keep moving in a straight line.
In order for the course to change, it is necessary to apply force. It's just ordinary physics.

The propeller from the main propulsion not only provides the main propulsen, but as an unwanted side effect also a sideways force. When going straight under power the rudder (or a asymmetric hull shape ) has to compensate for this. When the motor (und thus the propeller) stopps, chances are that the propeller slows down the ship a little and produces an opposite side force too.
So the main engine stop not just slows down the ship, but also makes the ship turn. To keep the ship straight after the power loss they need a correction by the rudder.
My point is that this is not a surprising effect and the emergency generator should get steering back fast and powerfull enough to not get such a large excursion from the normal course.

In addition there was also some (though not very strong) wind pushing the vessel to the side it finally went. The the propulsion is lost the rudder gets less effective and thus additional correction needed.

Even in just a "bay" there can be quite some tidal currents. With the shipping channel and relatively shallow otherwise I would not expect the currents to be much sideway though. At least the pilots should have known (such local knowledge is the main reason for habor pilots) and we would have heard about this.
 

Online soldar

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #197 on: May 17, 2024, 08:45:35 am »
Even better. They could have tried, i mean they had nothing else. Probably at time they were half asleep and thought they can do nothing.
I take this as a throwaway comment without intention of substance but all indications are that the crew, including the pilot, acted very well, very professionally. Nobody was "half asleep". They acted fast and correctly.


https://www.washingtonpost.com/dc-md-va/2024/03/26/pilot-anchor-turn-baltimore-bridge-collapse/

Pilot on board the Dali tried to slow ship before it struck Key Bridge

The specially trained pilot ordered the rudder turned hard to the left and an anchor drop to steady the ship and slow it down, an industry official said

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Online Ice-Tea

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #198 on: May 17, 2024, 08:48:37 am »
The balckout was from the brakers at the transformer tripping. From the reports the genrators were still running OK and thus the high voltage supply electricity from which the bow thruster would run still active.

Yes, but there was no means to activate the truster as the LV bus was down (and thus navigation). When the EG kicked in there was a small window where they could have used the bow truster but following a blackout of (at that time) unknow origin you don't exactly wan't to dump a 3MW load on the HV bus (aside from it being, as you mentioned, probably being of little use at higher speeds). At the very minimum the bridge would have had to contact the ER and those fellows were kinda busy. It would also have been a shortlived triumph as shortly after that a second blackout occured, this time tanking the DGs and thus the HV bus (which is kinda weird, there doesn't seem to be an actual reason for them to go down).

TBH, it looks like pretty much everyone did what they could do with the time and lack of hindsight offered to them.

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #199 on: May 17, 2024, 08:55:29 am »
Such massive vessel could not independently change its trajectory. Even if it is allowed to drift, it will continue to move on the same course. Keep moving in a straight line.
In order for the course to change, it is necessary to apply force. It's just ordinary physics.
The conclusion suggests itself: technical malfunctions do not matter, since there was an incorrect select for the trajectory of movement.
At least in the adjacent section of the fairway.
You have no idea about the complexity of this. In the Bay there are river and tidal currents. A vessel is subject to a multitude of forces. The rudder, the prop, the proximity to the bottom and the irregular shape of the bottom, the currents, the wind, etc. You have no idea how complex it is.
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Online dietert1

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #200 on: May 17, 2024, 05:40:17 pm »
I found this info on thrusters:
https://www.marineinsight.com/tech/bow-thrusters-construction-and-working/

They say:
"Bow thrusters are generally used to maneuver the ship near coastal waters and channels or when entering or leaving a port during bad currents or adverse winds.
Bow thrusters help tugboats berth the ship to avoid unnecessary time and, eventually, money wastage because the vessel stayed less in the ports. The presence of bow thrusters on a vessel eradicates the need for two tugs while leaving and entering the port, thus saving more money."

So i don't understand what is meant by a bow thruster being ineffective. Where does this idea come from?
I estimated a bow side-shift of about 27 m after running a 4 MW thruster for 180 seconds.
It's a fact that the hazard occurred after midnight when everybody needs a rest.
The question i asked will be asked anyway. There will be enormous legal fights about this. They caused a tremendous hazard and killed six people.

Regards, Dieter

« Last Edit: May 17, 2024, 08:20:52 pm by dietert1 »
 

Online soldar

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #201 on: May 17, 2024, 11:59:43 pm »
You are out of your depth here.
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Offline Andy Chee

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #202 on: May 18, 2024, 12:48:15 am »
A bit of trivia:

Looks like Google Streetview has stopped "travel" over the Francis Scott, despite being intact in cyberspace!

https://maps.app.goo.gl/EQ9Q9w5jR4qMU5KS7
 

Offline Andy Chee

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #203 on: May 18, 2024, 01:05:55 am »
I estimated a bow side-shift of about 27 m after running a 4 MW thruster for 180 seconds.
No power.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #204 on: May 18, 2024, 04:43:55 am »
It is a bit odd design with the main motor shutting down even with a rather short interruption of the generators.
The engine will stall if the blowers are not running.  The engine cannot breathe on it's own at low power.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #205 on: May 18, 2024, 06:59:56 am »
Two stroke diesel can't breathe on its own at all. If its scavenge air blowers stop the engine stops, period. The blowers are integral part of the engine operation cycle, unlike 4 stroke engine.

However at most operating range other than very low load (<25%) its exhaust should be enough to self sustain the turbocharger without needing auxiliary powered blower.
« Last Edit: May 18, 2024, 07:06:56 am by ArdWar »
 

Online dietert1

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #206 on: May 18, 2024, 07:20:19 am »
I estimated a bow side-shift of about 27 m after running a 4 MW thruster for 180 seconds.
No power.
Read preliminary report. From first electrical problem to crash were about 5 minutes with two outages of about 1 minute each. That's why i assumed 3 minutes = 180 seconds.
 

Online Ice-Tea

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #207 on: May 18, 2024, 09:28:23 am »
Read preliminary report. From first electrical problem to crash were about 5 minutes with two outages of about 1 minute each. That's why i assumed 3 minutes = 180 seconds.

* You don't use a bow truster at that speed. Good chance the controls are labelled to avoid some clown to try that anyways.
* You don't launch a 3MW load on an electrical net that is already troubled. In other words: the occurance of the second blackout was unexpected and unlikely but you would increase the chances of it occuring by an order of magnitude by launching the bow truster.
* After the second blackout, power was restored but only DG2 was running. Launching the bow truster at that time would have caused a guaranteed fresh blackout.

There are very few things you can do on board such a ship that would cause a blackout under normal conditions. Running the bow truster with an unprepared ER is one of them.

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #208 on: May 18, 2024, 10:07:49 am »
* You don't use a bow truster at that speed. Good chance the controls are labelled to avoid some clown to try that anyways.
* You don't launch a 3MW load on an electrical net that is already troubled. In other words: the occurance of the second blackout was unexpected and unlikely but you would increase the chances of it occuring by an order of magnitude by launching the bow truster.
* After the second blackout, power was restored but only DG2 was running. Launching the bow truster at that time would have caused a guaranteed fresh blackout.

There are very few things you can do on board such a ship that would cause a blackout under normal conditions. Running the bow truster with an unprepared ER is one of them.


Furthermore, from the plan shown in the preliminary report, it seems the Dali started veering to starboard only after the second power failure.

The report says:
Quote
The loss of electrical power stopped all three steering pumps, and, therefore, the rudder was unable to be moved. At the time, the ship was on a heading of 141.7°, a course over ground of 140.8°, and speed over ground of 9.0 knots, with the rudder amidships (0°).

At 0126:02, the VDR, which had stopped recording vessel system data when the blackout occurred, resumed recording the data. The VDR audio recording had not been affected by the blackout. The Dali’s heading was 144.3° and course over ground was 142.7°. Its speed over ground was 8.6 knots. The apprentice pilot called the pilot dispatcher by mobile phone. At 0126:13, the senior pilot, who had regained control from the apprentice pilot by this point, ordered 20° of port rudder.

The discrepancy between the ship's heading and COG, Course Over Ground, indicates the effects of currents and winds which are very changing in that area.

We will have to wait to find out why the electric power failures but it seems to me the crew were first class and acted decisively, promptly and professionally.

Anyone who thinks they know how to do better just does not understand the magnitude and complexity of the problem.

It seems the ship had been running on trafo #2 for months without problem and due to a mistake made by a crew member while in port they decided to run on trafo #1. It could be unrelated but there is a good chance this is the root of the problem and what triggered the whole incident. It will be interesting to see what comes out later.
« Last Edit: May 18, 2024, 10:23:05 am by soldar »
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Online dietert1

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #209 on: May 18, 2024, 10:47:25 am »
They write the circuit breakers of the two generators 3 and 4 tripped when the second blackout happened. They don't say the  generators stopped. I understood they had three HV generators and the LV emergency generator running. If necessary they could have used the fourth generator, too.
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Online Ice-Tea

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #210 on: May 18, 2024, 11:36:16 am »
The clown remark was aimed at a hypothetical deck officer that would need a reminder not to use the bow truster above a few kn, not you.

Once again, you don't launch the bow prop if the ER is unprepared or, worse, recovering from a blackout. That is how you create accidents, not how you avoid them.

Note also that the NTSB report doesn't even mention the availability of the bow truster. It would seem that for them, it's not even a topic as there is no expectation or desire to have that as an option.

When the breakers for DG3 and DG4 tripped there was a reason for that. They may have been overloaded (in which case adding a huge additional load on the bus is kinda bad) or the DGs themselves may have experienced propblems causing speed and thus bus frequency to drop (which would make them too unreliable to put back on the bus).

And no, they could not have quickly started DG1. That one was not in standby.

And even if by some miracle there was a minor window in time where they could have reliably used a magic truster that works at higher speeds, then this would have been known in the ECR, not on the bridge.

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #211 on: May 18, 2024, 02:30:05 pm »
What other large loads are there on the HV bus besides the bow thruster? Seems like it would have made more sense to have the bow thruster be hydraulic and use HVDC for the electrical system.
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #212 on: May 18, 2024, 03:25:48 pm »
Probly only power distribution to reefers.

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #213 on: May 19, 2024, 06:00:39 am »
I mean can't a black out be caused by anything like sticky breakers and some short that burned itself out? if that is the case then so long it mostly cleared itself you can try to run the thing full power right away. there is a chance the trouble is at that point completely isolated (vaporized wire somewhere)

there is always a chance like a small breaker will fail, the load will be vaporized, the big breaker will trip. but after that its irrelevant like nothing was ever there.... the problem is isolated and you can run the circuit at its 100% capacity or even more since that load is gone

i mean its a shady condition and you wanna get that checked out right away but if your gonna crash you might as well try
« Last Edit: May 19, 2024, 06:03:28 am by coppercone2 »
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #214 on: May 19, 2024, 06:55:16 am »
From the chats I have had with a friend who spent most his life fixing big boats. He would always complain about the lack of spending, if there was a problem they would work around it until it was a big problem or they could dock somewhere where the labour was cheap enough, a bit like not going to the main dealer for a service but using a local independent.

I did lol at a bbc news article the other day that had the headline Boat Crew still Stuck on board. They were planning a long trip anyway but I think it was a slow news day and a reporter needed to up their word count.
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #215 on: May 19, 2024, 07:01:18 am »
I mean can't a black out be caused by anything like sticky breakers and some short that burned itself out? if that is the case then so long it mostly cleared itself you can try to run the thing full power right away. there is a chance the trouble is at that point completely isolated (vaporized wire somewhere)

* There probably wasn't enough power after the first blackout
* There was no reason to even try after the first (heading)
* There surely wasn't enough power after the second blackout
* Restoring propulsion would have been orders of magnitude more effective, so why waste time and effort on that.

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #216 on: May 19, 2024, 07:04:16 am »
What other large loads are there on the HV bus besides the bow thruster? Seems like it would have made more sense to have the bow thruster be hydraulic and use HVDC for the electrical system.

And how would you power the hydraulic pump that drives your hypothetical hydraulic bow thruster?
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #217 on: May 19, 2024, 09:28:00 pm »
And how would you power the hydraulic pump that drives your hypothetical hydraulic bow thruster?
Mechanically from the auxiliary engines.
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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #218 on: May 20, 2024, 12:33:56 am »
Mechanically driven "Z-drive" bow thrusters are pretty common. Its just that it's uncommon for this kind and size of vessel since it requires placing a diesel engine at a remote location, which also requires engineer to attend during operation. Hardly any safer, and importantly more $$$ to operate.

Hydraulic driven bow thruster (actual hydrostatic drive, with pump-motor pair) also exist(ed). It just that it's probably not exactly what you want since the hydraulic line is only used to bridge the small gap between thruster hub and ship hull. You still need a diesel engine or electric motor close by to run the pump which doesn't exactly simplify things from how it is currently done.
 

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Re: Baltimore Francis Scott Key Bridge collapse
« Reply #219 on: May 20, 2024, 12:37:23 pm »
Chief Makoi on the NTSB report:

 
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