Key Bridge in Baltimore collapses after being hit by a container ship

volchitsa

https://www.boards.ie/discussion/comment/121947662#Comment_121947662

Maybe I don't know my history, but I always had the impression that the US was FAR more responsible for the perilous state of affairs in the Middle East than Ireland is.

So unless you can show me why Irish people should be paying more to fix the Middle East than America should, I'm gonna stick with my comparison.

Overheal

https://www.boards.ie/discussion/comment/121947659#Comment_121947659

This bridge had about 35,000 vehicle movements a day. About a fifth of what the M50 gets.

It was also much shorter, 1.6 miles vs. 28.3 miles (with multiple access points for the latter). Hard to directly compare an entire city's bypass to a single bridge.

I only traveled through Baltimore on my way to Maine the one time, over 10 years ago, couldn't tell you anymore if we took the francis scott bridge or the toll tunnel or Ft. McHenry, but pretty sure one of the latter because the FSB snakes a while before returning to I95.

Overheal

https://www.boards.ie/discussion/comment/121947682#Comment_121947682

"But as your post alludes, there's already a thread for that where you can leave your diatribe."

volchitsa

https://www.boards.ie/discussion/comment/121947698#Comment_121947698

LOL different point though. If you agree that marine traffic to/from the US being blocked is as important - or not - as traffic through the Red Sea to Europe, that's fine. It's just you came across as rather glad that European populations were going to lose out, and that it was all only "cheap Chinese ****" anyway, and never mind if sailors from poor countries died - so I think you should take the same approach when it's the place you live in.

Unsurprisingly though, you haven't. But I notice you were as quick as Donald Trump to forget America's role in the shitstorm that is the middle east, though even he hasn't yet tried to blame the Irish for it.

Overheal

https://www.boards.ie/discussion/comment/121947794#Comment_121947794

See Post #246. Seems you're much more interested in discussing that thread, but on this one.

jackofalltrades

https://www.boards.ie/discussion/comment/121944394#Comment_121944394

They let go the port anchor, in the hope of turning the vessel to port.

At the speed that they were doing and the proximity to the bridge it's unlikely that it would achieve much. It's more of a Hail Mary move.

https://www.boards.ie/discussion/comment/121944495#Comment_121944495

Ships need a bit of work to keep them on one heading(keep them going straight). They'll usually want to turn one way or the other.

When a ship like this blackout, it's rudder is stuck in the position it was in when the power went. So unless the rudder was midships (centred as you call) it's going to keep turning.

When the emergency generator was up and running and feeding power to the ships steering gear they would have been able to steer again. Although with the engines not running the steering won't be as effective. And it will be slower to respond as only one steering pump would be running.

Then you have the wind, current and tides acting on the ship as well possibly making the situation worse.

Hope that explanation makes sense.

ProfessorPlum

https://www.boards.ie/discussion/comment/121948058#Comment_121948058

Is there evidence though that the engine failed? It looks like the power failed, possibly affecting the power to the rudder for steering control. There's massive plumes of black smoke in the couple of minutes before impact - I wonder did they try to go to full reverse/ astern. That would possibly make the rudder even less effective and the engine moment itself will have a turning effect on the ship. Looking at the track it made before it hit the bridge, it certainly seems to have made a significant turn to starbord (and then a very slight port turn, presumably due to the anchor)

Absolutley astonishing that there was not a better redundancy to the rudder, particularly in port.

Overheal

https://www.boards.ie/discussion/comment/121948109#Comment_121948109

A rudder without power/hydrodynamic pressure, is next to useless. The ship was already moving quite slow. And those big cargo rudders work mainly by deflecting the power directly coming from the screws. At best it could have a marginal effect on spinning the ship's mass without power to the drive, but that would only affect which end of the ship hits whatever the center of mass is already headed toward. For those speeds and that relative mass and size, the direction it's pointed is not going to have the dominating influence on where the ship goes, not without engine power to forward/reverse.

JupiterKid

This could have been so much worse in terms of human tragedy if that ship has struck the Francis Scott Key Bridge at rush hour instead of 1.30am. RIP to those workers on the bridge who lost their lives.

Could the design of the FSK bridge that failed in a spectacular fashion immediately after it was struck by the huge container ship be in itself inherently unsafe?

There seems to be many road and rail bridges throughout the USA built during the 20th Century of a relatively similar metal truss cage design to the FSK bridge and I wonder - deterioration due to ageing, corrosion and inadequate maintenance issues notwithstanding - will they need to be re-evaluated in terms of their inherent safety and be replaced? 

Would cost-cutting have been a factor in the FSK bridge design that contributed to the rapid collapse? I presume this will be addressed in the inquest into the tragedy.

I.am.Putins.raging.bile.duct

https://www.boards.ie/discussion/comment/121948129#Comment_121948129

I learned this the hard way trying to steer a barge on the Shannon

Overheal

https://www.boards.ie/discussion/comment/121948192#Comment_121948192

I was never in charge of anything quite so large but even on recreational and fishing boats it's a learning curve you don't soon forget

Overheal

https://www.boards.ie/discussion/comment/121948178#Comment_121948178

No suspension bridge is built to survive one of its only 2 sides' pillar suddenly collapsing underneath it, and pillars themselves cannot readily be designed to resist the impact of a ~85,000+ ton cargo ship crashing into it. The Tampa Sunshine Skyway Bridge demonstrates using separated bollards for protection, bollards which are designed to be hit/deflect energy away from the bridge structure itself. It's not that the bridge was inherently unsafe imho it's that you inherently cannot make a waterway bridge entirely failsafe, and this was a failure mode, one they typically account for by having mandates that local pilots be escorted on board the vessels to do all the driving of the ships inside the harbor zones, who have local tribal knowledge of the estuary etc.; beyond that I wouldn't want to speculate too much ahead of a full investigation to what happened. I imagine whatever replacement happens for the destroyed span it will include bollards or similar added redundancies similar to those in the Tampa bridge (which also only has them because of a previous collision decades ago, which destroyed the original bridge). Arguably they overengineered the safety features of the bridge based on that experience and it didn't apparently make it to being an adopted standard nationwide nor globally. Blame the actuaries or blame politicians, I don't really know which.

https://www.wtsp.com/article/news/local/pinellascounty/bridge-collapse-baltimore-skyway-tampa-rebuild/67-6f876ecf-4a1e-49f9-a3f8-df5ab340488f

https://www.youtube.com/watch?v=9N1HUQVpIgA

Documentary:

https://www.youtube.com/watch?v=3htwtaJI2nM

I think I may have rode over the completed replacement span when I was much younger, in the early 90s.

The cargo ship that crashed in Baltimore was ~3x the mass.

I.am.Putins.raging.bile.duct

^^^Excellent post watch all the video it's eye opening

ProfessorPlum

https://www.boards.ie/discussion/comment/121948129#Comment_121948129

I didn't see it reported definitively that it had lost engine power, hence my comment. I'm not familiar with the rudder / prop arrangement in large ships (I do know plenty about rudders and aerodynamics) but putting the prop into reverse will affect the effectiveness of the rudder by disrupting flow over the rudder. If the engine did fail, then looking at the arrangement in your post above, it's easy to see why any amount of deflection on that rudder would be ineffectual - it's tiny! (I'm more used to dealing with airborne rudders) Will be interesting to see the NTSB report.

jackofalltrades

https://www.boards.ie/discussion/comment/121948109#Comment_121948109

From here. It's not concrete evidence but it's being widely reported.

An unclassified memo issued by CISA, the Cybersecurity and Infrastructure Security Agency, said the ship reported losing propulsion.

I too saw the thick black smoke and wondered if they had managed a restart or got the ship going full astern.

Rudder redundancy is actually quite good on ships like this, in theory. This ship has 4 generators (reported by WIKI and Daily Kos) as well as 2 separate steering gear pumps. While navigating in port I'd expect the majority or all of them to be running. If all 4 generators fail and/or the main switchboard fails then you still have the emergency generator which has it's own switchboard and is capable of powering one of the steering gear pumps. And even then you should only be without rudder control for about 45 seconds max.

Overheal

https://www.boards.ie/discussion/comment/121947080#Comment_121947080

and here’s that culture war now. Were it a Florida or Texas bridge they wouldn’t have said a word out of turn

https://www.mediaite.com/tv/outrageous-house-republican-slams-biden-over-promise-to-use-federal-funds-on-collapsed-baltimore-bridge/

silliussoddius

They'll probably take credit for it after it's rebuilt.

Overheal

https://www.boards.ie/discussion/comment/121950790#Comment_121950790

even after they vote to block any help for it.

Kiwi John

https://www.boards.ie/discussion/comment/121945455#Comment_121945455

10,000 is.for 20ft containers. 5000 40ft containers and most in the pictures are 40ft so it would be close to fully loaded

Igotadose

Watched CBS news this a.m.. "The US Navy is sending the largest marine crane on the East Coast to help out. It's capable of lifting 1000 tons (US) at a time, and it won't be big enough."

There are chunks of bridge heavier than that, and they need to excavate a 50 foot deep channel. Biden made the Army Corp of Engineers drop what they're doing and scramble. Their commander said it will take at least 2 years.

railer201

https://www.boards.ie/discussion/comment/121949075#Comment_121949075

In addition to the rudder, and independent of it - 'transverse thrust' or 'propeller walk' is a secondary manouvring feature of ships with single screw propulsion, in that when going astern the wake travels back along the hull but is also spinning anti-clockwise, pushing against the hull/skeg on the starboard side. This has the effect of turning the ship to starboard.

Basically a single screw vessel can manouvre to port or starboard from standstill with short bursts of power, using the rudder or transverse thrust.

Overheal

https://www.boards.ie/discussion/comment/121953741#Comment_121953741

And what they were doing was… geez

https://www.reuters.com/world/middle-east/us-says-building-gaza-port-take-likely-up-60-days-2024-03-08/

ProfessorPlum

https://www.boards.ie/discussion/comment/121953754#Comment_121953754

Thanks for that - that's what I was trying to get at in this post. Couldn't remember the proper term for it.

https://www.boards.ie/discussion/comment/121948109#Comment_121948109

robinph

https://www.boards.ie/discussion/comment/121953741#Comment_121953741

Not going to take 2 years to get the wreakage moved so the port can reopen. 2 months would feel like they were dawdling about it.

Rebuilding a bridge is another matter.

jackofalltrades

I'd estimate that they'll have the channel under the bridge cleared fairly quickly. The steel superstructure of the bridge is the main issue. That seems to be fairly intact. Cut it up and remove it piece by piece. Once that's gone there may be debris on the bottom of the channel, but it not going to have the same height and potential to cause blockage as the steel superstructure would.

Also not all ships will need the full 50 feet (15.24 metre) depth that the channel originally had. The widest span is 366m, which I'm assuming is in the middle of the bridge between the two piers. You don't need to fully clear that to open the channel. A 100/150 meter wide channel with tug escorts at slow speed would probably be wide enough for most ships.

aidanodr

Fool me once?

https://twitter.com/johnkonrad/status/1776786983097966862