Baltimore bridge collapse

Skybolt said:
It is all speculation, but in that vid you can clearly see the ship swing hard to stb then they collided with the bridge. It's like the port engine didn't go into reverse.
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According to Wikipedia, the ship is single screw, MAN diesel with fixed pitch prop. Prop walk in reverse could account for the swing.
 
alnav said:
According to Wikipedia, the ship is single screw, MAN diesel with fixed pitch prop. Prop walk in reverse could account for the swing.
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So much for my conjecture. Thanks for clearing that up Al. So the harbor pilot didn't have much to work with then I guess. The question still remains on why they were so far off of the center of channel.
 
Skybolt said:
So much for my conjecture. Thanks for clearing that up Al. So the harbor pilot didn't have much to work with then I guess. The question still remains on why they were so far off of the center of channel.
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The captain doesn't relinquish control of his/her boat and is always responsible for the safety of the boat and crew, even when a pilot is onboard. If the pilot suggested they go full-astern when power came back on, the captain would still be responsible to know that the bow was going to move to starboard, not the pilot.

EDIT - Don't we have anyone around here that worked on big boats??? I just read it takes 10-15 minute to reverse a direct drive diesel engine, and the boat has to be at a complete stop to do it. If that's true there's no way they put this boat into reverse during/between these power failures. Hmmmm...

I also wonder if the crew was more worried about the lighthouse/island on the other side of the bridge when they made the decision to reverse. They could have coasted safely under the bridge but maybe they felt they were running out of room to avoid the island...it starts getting pretty shallow right on the edge of that shipping channel.

The write up on this thing will be fascinating.

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Skybolt said:
So much for my conjecture. Thanks for clearing that up Al. So the harbor pilot didn't have much to work with then I guess. The question still remains on why they were so far off of the center of channel.
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Found this video which synchs up the video with the MarineTraffic track and provides some additional conjecture including about the backing bell. But, it also raises the notion that the power loss may have frozen the rudder.
 
alnav said:
Found this video which synchs up the video with the MarineTraffic track and provides some additional conjecture including about the backing bell. But, it also raises the notion that the power loss may have frozen the rudder.
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Very interesting analysis. Great vid on this.
 
West Coast said:
Would you rather they wait and litigate or fix the bridge and go after the company and insurance after? Hope they get it fixed and my heart goes out to all involved in this tragedy!
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I would rather the federal government stay out of it completely, the empire state building was built in a year in 1930, we can accomplish great things, if allowed.
 
JayhawkCurtis said:
I would rather the federal government stay out of it completely, the empire state building was built in a year in 1930, we can accomplish great things, if allowed.
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Once the money is provisioned, it will be of most importance to get the correct Union GC for this job.
 
alnav said:
According to Wikipedia, the ship is single screw, MAN diesel with fixed pitch prop. Prop walk in reverse could account for the swing.
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I’m curious if the ship would have remained without power, and no evasive action was taken what the damage would be, looks like to me it might have been more of a glancing blow if it would have stayed on its course dead atick
 
Skybolt said:
It is all speculation, but in that vid you can clearly see the ship swing hard to stb then they collided with the bridge. It's like the port engine didn't go into reverse.
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i figured the swing was caused by dropping anchor when they lost power. Guess we'll know eventually.
 
Just a bit more information on the MV Dali:


Dali is propelled by a single low-speed two-stroke crosshead diesel engine coupled to a fixed-pitch propeller. Her main engine, a 9-cylinder MAN-B&W 9S90ME-C9.2[11] unit manufactured by Hyundai Heavy Industries under license, is rated 41,480 kW (55,630 hp) at 82.5 rpm.[2] Her service speed is 22 knots (41 km/h; 25 mph).[5] For maneuvering in ports, Dali has a single 3,000 kW (4,000 hp) bow thruster. Electricity is generated by two 3,840 kW (5,150 hp) and two 4,400 kW (5,900 hp) auxiliary diesel generators.


This probably raises a few more questions. If they lost electrical power.....apparently at least one of the generators shut down. Losing the electrical power AND propulsion is really unusual. Usually the generator and propulsion have different fuel tanks and filter systems. It is almost as if the fuel valves were closed.
 
Chris L said:
THat would be ideal, but i have a feeling they'll want to get the ports up and operational ASAP. Thus, a bridge. Maybe a temp bridge followed by a tunnel..
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alnav said:
Found this video which synchs up the video with the MarineTraffic track and provides some additional conjecture including about the backing bell. But, it also raises the notion that the power loss may have frozen the rudder.
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Doesn’t look like prop froze to me. In fact the ship accelerated before hitting bridge support. Lots of conjecture and will take time to analyze the black box. Not to be a conspiracy theorist but what if it was done on purpose? I think they would be able to figure that out.
 
Mauler34Rod said:
Doesn’t look like prop froze to me. In fact the ship accelerated before hitting bridge support. Lots of conjecture and will take time to analyze the black box. Not to be a conspiracy theorist but what if it was done on purpose? I think they would be able to figure that out.
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I believe the rudder is electrical/hydraulic controlled and would have been unresponsive if they lost complete power.

I will bet based on what has been released so far.....the root cause will be a maintenance issue and that the crew was not prepared for Departure.

As to speed at impact......it was slowing at least according to AIS/GPS data.
 
Mauler34Rod said:
Doesn’t look like prop froze to me. In fact the ship accelerated before hitting bridge support. Lots of conjecture and will take time to analyze the black box. Not to be a conspiracy theorist but what if it was done on purpose? I think they would be able to figure that out.
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It's not impossible but probably improbable. If this was done on purpose, why not do it during rush hour or midday where there could be mass casualties?
 
OllieC said:
It's not impossible but probably improbable. If this was done on purpose, why not do it during rush hour or midday where there could be mass casualties?
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True that, but what if taking out the port was the task?
 
Local news this morning says the mayday was for loss of steering. Police radio recordings now out say the same thing. I believe there are traffic control lights that were able to be used to stop traffic quickly. The police recordings mention warning the work crew but there was only about one minute from when the voice alert started until the bridge collapse.
 
Pirate Lady said:
Some new info…
There were 2 harbor pilots aboard.
Most bridges are not built to withstand the impact of the ships that were unimaginable in the 70s when this was built.
Ship is the size of aircraft carrier.
This wont be the last collapse of this kind.
The 6 missing may be buried in the mud under tons of steel, probably never gonna be found. Does this make it a graveyard?
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I am guessing there was a harbor pilot who was responsible for getting them off the pier and out the channel. There definitely would have been a Chesapeake Bay pilot who would drive the rest of the way and not get off until past Cape Henry at the entrance to the bay and he/she probably got on at departure just to avoid one boat transfer. Not sure but I don't think the Bay pilots do harbor work.
 
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