Baltimore Francis Scott Key Bridge collapse

[JustMeHere]

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.

[SiliconWizard]

Some analysis:

[guenthert]

[..]
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.

[EEVblog]

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

[langwadt]

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

[SiliconWizard]

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.

[soldar]

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

[AlfBaz]

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

[langwadt]

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

[ZigmundRat]

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

[floobydust]

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.

[soldar]

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.

[RJSV]

   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

[guenthert]

   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.

[Ice-Tea]

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.

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.

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.

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.

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?

[Kleinstein]

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.

[m k]

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?

[langwadt]

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

[David Hess]

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.

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.

[JustMeHere]

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.

[JustMeHere]

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.

[DiodeDipShit]

Bound to happen, a very slight base, no surrounding bumpers .....

[NiHaoMike]

[soldar]

How Bridge Engineers Design Against Ship Collisions

[floobydust]

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!