Baltimore Bridge collapse after ship collision 125

[Tomfh]

https://amp.9news.com.au/article/b73620ea-64ab-4253-8cb0-37102418fcab

 

[Oops409]

I am having a hard time understanding how a lean fuel mixture causes constant black smoke out of diesel generator?

If you modify a diesel truck to ‘RollCoal’, you are forcing a higher fuel to air ratio into the engine to create the black smoke.

Black Smoke seems to indicate richer fuel to air ratio, or flooded condition. Like the air intake or forced air intake is not powered?

 

[TugboatEng]

It doesn't. We don't know if the black smoke was coming from the generators or main engine. This ship is a 2016 build so it has electronic controlled engines that should not smoke black like that under any conditions. However, if the ship was operating at slow ahead it was likely utilizing the auxiliary blowers for scavenging on the main engine. A loss of power may have caused the aux blowers to stop before the engine tripped which would cause a lot of black smoke.

 

[Oops409]

Tug, how does the system adjust fuel flow based upon the different grades of fuel used? I had read perhaps 3 different mixes or grades of diesel/fuel oil is used, depending on proximity to land.

 

[TugboatEng]

The engines don't do any adjustment. They have only a constant speed governors that increases or decreased injection quantity based on engine speed and load.

The ship does have a viscosimeter is referenced to adjust fuel temperature. Transitioning from heavy fuel to distillate fuels is challenging because viscosity must be maintained while decreasing temperature simultaneously. This would never be done while maneuvering.

 

[hokie66]

You have to feel for the crew who are stuck on the ship.

https://edition.cnn.com/2024/05/18/us/baltimore-bridge-dali-ship-crew/index.html

 

[TugboatEng]

Don't forget that when these ships are at sea there is no cell service. Conditions on the ship are not very different from normal, probably just quieter without the main engine running.

 

[SwinnyGG]

The engines don't do any adjustment.

This IS how they do the adjustment:

They have only a constant speed governors that increases or decreased injection quantity based on engine speed and load.

When I worked in dev at DD a long time ago, significant variations in fuel quality were tested, and data was gathered that effected design decisions on the fuel/fuel control systems.

 

[Oops409]

A quick google suggests there is a lot of manual sub-systems(even with automated systems) valves, controls, gauges, etc. that go into controlling viscosity and condition of the heavy oil fuels, low sulfur fuels, distillate fuels, etc., prior to reaching the combustion chamber of the large container ship engines, generators, boilers, etc. Then there are the monitoring sub-systems to dial in the fuel to air ratio for the particular fuel in use, and load.

It was Jan 1, 2015 when MARPOL Annex VI ultra-low-sulphur fuel oil regulations that changed rules on fuels. I read somewhere in this thread that this ship was manufactured around that time. Question is was it built before of after the new rules? Did it have to be retrofitted after new rules, and perhaps multiple times since it was manufactured to meet changing environmental rules and fuels or was it grandfathered?

Could the sudden loss of load on DGR3 and 4, be the cause of the black smoke due to loss of all electrical loads on main generators?

I believe this article also mentions turning off one generator when loads are too low for two generators, to ensure turbo is spun up sufficiently to create proper fuel to air ratio. Or did a ship mate close or open the wrong manual control device, at that the wrong time, in preparation for open sea conversion to heavy fuel oil?

I have highlighted the load scenario in the screen shot below, and provide link to the Marine Insight article.

https://www.marineinsight.com/tech/black-smoke-coming-ships-funnel-port/

I have also included a MAN Dec 2014 Service letter concerning low sulfur fuels and low viscosity distillate fuels.

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1716145445/tips/sl2014-593_uwhp83.pdf[/url]

Bottom line is it appears effects of running multiple fuels and tuning of engines to run on different fuels is a very complex process, and perhaps with a lot of manual intervention to control the process. So plenty of room for human error, in spite of automation systems, just like the exhaust damper was incorrectly close in port?

 

[TugboatEng]

It would be colossally stupid and illegal to change fuels while maneuvering. I don't think this is an avenue that needs to be explored.

 

[Roga50]

I think it was Chief Makoi who even spoke about changing fuel types in a video a while back. It is not an instantaneous switch--you have to do it gradually (meaning the fuels are mixed during the process), so it takes a while to complete. There is an (old) Kongsberg MC90-V engine room simulator (you will find a ton of videos on this on YouTube--I think even Chief M has used it to illustrate some things in the past). This simulator does simulate the changeover process, amongst other things, and from what I remember it takes well over an hour. I have that simulator installed too, have not re-tried changeovers (too time consuming). It also does simulate the viscosity controls but I have never quite been able to get that right (I always had a lot of problems keeping it in range).

Edit: here's the video from Chief M Link

 

[LittleInch]

Lots of unknowns here.

So e.g. when the 440V breaker tripped, did it trip all the breakers? Was there any UPS involved in the board control circuits and voltage.

So when they restored power to the 440V board, did then they need to reconnect all the breakers? Did the control circuit / software die as well?

How long did it take the main engine to die?

I would have thought the EG would or should be on line and connected to the emergency board within 15 seconds. Then it's a matter of how long it took for the crew to connect the DG2 fuel pump and start the DG2.

The EG normally doesn't connect onto the main 440V bus as it just isn't man enough. It's not called Emergency for nothing.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Oops409]

Tug, you totally missed the point of my post or did not read it or understand it?

I am thinking way beyond what you are thinking. The point was it is a complex process and takes preparation and time, and proper preventive maintenance.

I would not see why they were not already heating the heavy fuel oil tank as that has to be done and stabilized before even thinking about changing fuels.

Tug, you have stated earlier no way black smoke should be coming out! Something was not right.

They had fuel problems in port on distillates, and that was what they were running on when they hit bridge.

Switching fuels involves more complex fuel systems than a single fuel motor. More complexity = more potential for errors or failures.

Roga, thanks for the link to the video, and it shows it is a complex manual and automated process to be running an engine on multiple fuels. In video it was a 4 hour process to change over from heavy to light.

 

[hokie66]

The Dali is set to be refloated and removed from the channel soon. Then the rest of the debris can be cleared and the main channel reopened. This article shows a good view of the exploding charges which cut most of the remaining truss sections away.

https://www.foxbusiness.com/economy...baltimore-bridge-collapse-removed-within-days

 

[Sym P. le]

From YouTube StreamTime Live chat:

They added a heap of ballast, and reports are it's been moving slightly in the storms/tide so should hopefully break free without too much hassle

Is the movement fact or rumour?

 

[TugboatEng]

I would assum only the bow is sunk so the rest of the ship is still buoyant and will show some movement.

 

[JohnRBaker]

The Dali has been re-floated and is being moved to a dock:

Cargo Ship That Crashed Into Baltimore Bridge Heads Back to Port

The Dali, which had been pinned in by the wreckage of the Francis Scott Key Bridge since late March, began moving again early Monday.

https://www.nytimes.com/2024/05/20/us/dali-moving-key-bridge-baltimore.html

An excerpt from the above item:

Nearly eight weeks after it rammed into the Francis Scott Key Bridge, tearing down a Baltimore landmark but becoming a fixture on the horizon itself, the container ship Dali is afloat again. More than an hour after an expected 5:30 a.m. start, the ship, surrounded by tugboats, began a two-and-a-half mile journey back to a berth in the Port of Baltimore.

The moving of the Dali is a crucial step in the effort to fully reopen the main channel to the port, which was blocked in the early hours of March 26, when the Dali lost power and hit the bridge. The bridge collapsed on impact, killing six workers doing repairs on the bridge roadway, clogging the waterway with around 50,000 tons of metal and debris, and disrupting the commerce of one of the nation’s key shipping hubs.

The salvage and recovery operation has involved more than a thousand workers and scores of barges, cranes, helicopters and Coast Guard cutters. Access to and from the port has returned piecemeal: On April 1, a temporary channel opened with a depth of 11 feet; in the days and weeks since, other channels were opened with depths of 14, 20 and 45 feet.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[Sym P. le]

Juxtaposition. A ship can destroy an immovable object and sail away.

 

[Nukeman948]

Well I guess that depends on your perspective. The ship had to be dragged away from the scene and the immovable object fell into the bay.
So just what is an immovable object when we are on a spinning planet orbiting a star that is rotating around the center of our galaxy in an ever expanding universe that some say may eventually reverse and collapse upon itself before exploding in another big bang. It all moves, and yet it doesn't.

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[Sym P. le]

And in the news today, is the Milky Way orbiting something, anything? We need to know!

 

[Oops409]

Here is a quote from a NY Times article:

“Investigators said the electrical problems in port began when crews were working on an exhaust scrubber system on one of the diesel engines. A worker mistakenly closed an exhaust damper, stalling the engine and shutting off the generator. Workers restored power for a short period using another generator, but insufficient fuel pressure caused an electrical breaker on that generator to trip.”

I can not find this scrubber statement in the NTSB preliminary report? Perhaps I missed it?

Could a Rigged or bypassed Scrubber Bandaid be what caused sudden black smoke?

Another variable for Little to add to his list!

A wet scrubber requires electricity to run pumps............