# Bridge collapse in Baltimore {2024-03-26} **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Tags:** breaking-news\ **Created:** [March 26, 2024, 8:11am UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372 "2024-03-26T08:11:34Z")\ **Posts on this page:** 20\ **Page:** 15
**Author:** ![Princhester](https://avatars.discourse-cdn.com/v4/letter/p/3e96dc/32.png) [@Princhester](https://boards.straightdope.com/u/Princhester)\ **Post date:** [March 29, 2024, 8:45am UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/281 "2024-03-29T08:45:10Z")
> [@Broomstick](#): > > If dirty crap had settled to the bottom of the fuel tank(s) it might have been stirred up again when more fuel was added, allowing the gunk to gum up the works? Ships have purifiers and settling tanks and all fuel is run through them before being burned. Dirty crap should not be in the fuel past that process. Having said, poor fuel is a real problem. A client’s vessel stopped dead a couple of weeks back mid ocean due (probably) to an off-spec fuel issue. > [@Pleonast](#): > > Has anyone seen an estimate of the mass of the tower that was struck? I’ve seen the estimates of the freighter _Dali_ being on the order of 100,000 tons. Anyone have a more precise gross tonnage? I’d like to congratulate the SDMB on reaching the 238th post in a thread about ships before someone made the volume/mass mistake. > [@The\_Stafford\_Cripps](#): > > Gross tonnage isn’t the figure you want, since it’s a confusingly titled measure of a ship’s volume for trade purposes. The term “ton” or “tonne” derives from the ancient word “tun” which means a large cask or barrel and was originally a measure of volume, not mass. The maritime industry continues to use the word correctly while the rest of the world get this wrong. 😉 ---
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [March 29, 2024, 9:21am UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/282 "2024-03-29T09:21:29Z")
> [@Princhester](#): > > The term “ton” or “tonne” derives from the ancient word “tun” which means a large cask or barrel and was originally a measure of volume, not mass. The maritime industry continues to use the word correctly while the rest of the world get this wrong. 😉 Doesn’t a ton (volume) of ship displace a ton (weight) of water? ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [March 29, 2024, 1:59pm UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/283 "2024-03-29T13:59:53Z")
> [@Alessan](#): > > Doesn’t a ton (volume) of ship displace a ton (weight) of water? If that volume is entirely below the surface of the water, yes. ---
**Author:** ![rocking\_chair](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rocking_chair/32/2918_2.png) [@rocking\_chair](https://boards.straightdope.com/u/rocking_chair)\ **Post date:** [March 29, 2024, 3:00pm UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/284 "2024-03-29T15:00:10Z")
i saw on cnn this morning that the 2 who survived the collapse were in the process of getting off the bridge. they heard/saw a responder motioning/ yelling to get off the bridge. “One of the survivors who I had the opportunity to speak with, one of the things he mentioned to me was as he was moving off of the bridge – and literally saw the bridge fall right after he moved off – it was because it was a first responder who was telling him to move off the bridge,” Moore said. That life-saving notification was made “audibly,” although other contact between first responders and workers may have been made by cellphone or radio, Moore said. i found an article: [Baltimore Key Bridge collapse live updates: Largest crane on Eastern Seaboard to help clear channel - ABC News (go.com)](https://abcnews.go.com/US/live-updates/baltimore-key-bridge-collapse/survivor-saved-by-first-responders-warning-just-before-bridge-fell-gov-moore-says-108602114?id=108500215) ---
**Author:** ![EddyTeddyFreddy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eddyteddyfreddy/32/18796_2.png) [@EddyTeddyFreddy](https://boards.straightdope.com/u/EddyTeddyFreddy)\ **Post date:** [March 29, 2024, 4:09pm UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/285 "2024-03-29T16:09:51Z")
> [@Mama\_Zappa](#): > > Still, imagine being in one of those last couple of vehicles, and realizing what you just dodged. I suspect those drivers went home afterwards and had a hell of a case of the shakes. I wonder whether they heard it go behind them, saw it in their rearview mirror, or whether they didn’t even know how close they’d come to a horrible death till they learned the news? Either way, yeh, major shakes. ---
**Author:** ![The\_Stafford\_Cripps](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_stafford_cripps/32/7167_2.png) [@The\_Stafford\_Cripps](https://boards.straightdope.com/u/The_Stafford_Cripps)\ **Post date:** [March 29, 2024, 4:11pm UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/286 "2024-03-29T16:11:31Z")
> [@Alessan](#): > > Doesn’t a ton (volume) of ship displace a ton (weight) of water? > [@Machine\_Elf](#): > > If that volume is entirely below the surface of the water, yes. Something on a ship that weighs a ton displaces a ton of water in the sea irrespective of whether that thing is above the waterline or not. But forget about that, forget about the volume that a ton of water occupies. They’re irrelevant since [Gross Tonnage](https://en.wikipedia.org/wiki/Gross_tonnage) is completely different. (And even if a gross tonnage of 1 was the volume of a ton in weight of water it would only displace that weight of water if whatever it contained had exactly the same density as water.) ---
**Author:** ![EddyTeddyFreddy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eddyteddyfreddy/32/18796_2.png) [@EddyTeddyFreddy](https://boards.straightdope.com/u/EddyTeddyFreddy)\ **Post date:** [March 29, 2024, 4:22pm UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/287 "2024-03-29T16:22:39Z")
Reading the [CNN article](https://www.cnn.com/2024/03/29/us/francis-scott-key-bridge-collapse-friday/index.html) about the largest crane on the Eastern Seaboard being brought in to help clear the wreckage, I see that > In addition to the crane, three heavy lift vessels are expected to start arriving Friday, US Transportation Secretary Pete Buttigieg told CNN. Also, that > But first, officials are conducting a full assessment of the debris pieces before they can be lifted from the water, US Coast Guard Rear Adm. Shannon Gilreath said. This appraisal is critical in determining how small to cut the bridge pieces so cranes can lift them, he said. This confirms my assumption that the bridge sections would have to be cut up before being lifted away. No doubt some of that cutting will have to be done under water, which is going to be a helluva difficult and dangerous job. No wonder officials are doing a careful assessment before starting the demolition work. ---
**Author:** ![The\_Stafford\_Cripps](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_stafford_cripps/32/7167_2.png) [@The\_Stafford\_Cripps](https://boards.straightdope.com/u/The_Stafford_Cripps)\ **Post date:** [March 29, 2024, 4:27pm UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/288 "2024-03-29T16:27:58Z")
The overall point being that to calculate the momentum of the ship you would use its displacement, and the weight of the goods it was carrying, and not the gross tonnage. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [March 29, 2024, 6:11pm UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/289 "2024-03-29T18:11:38Z")
> [@The\_Stafford\_Cripps](#): > > Something on a ship that weighs a ton displaces a ton of water in the sea irrespective of whether that thing is above the waterline or not. @Alessan’s question was about a ton of volume, not a ton of weight. ---
**Author:** ![The\_Stafford\_Cripps](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_stafford_cripps/32/7167_2.png) [@The\_Stafford\_Cripps](https://boards.straightdope.com/u/The_Stafford_Cripps)\ **Post date:** [March 29, 2024, 6:18pm UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/290 "2024-03-29T18:18:37Z")
> [@Machine\_Elf](#): > > @Alessan’s question was about a ton of volume, not a ton of weight. I’m sorry but this is all confused and unnecessarily confusing. ---
**Author:** ![Maserschmidt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/maserschmidt/32/18829_2.png) [@Maserschmidt](https://boards.straightdope.com/u/Maserschmidt)\ **Post date:** [March 29, 2024, 6:23pm UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/291 "2024-03-29T18:23:58Z")
A shipping ton is forty cubic feet of storage, and how much water it displaces will vary between say 40 cubic feet of lead and forty cubic feet of feather pillows. ---
**Author:** ![DavidNRockies](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/davidnrockies/32/6279_2.png) [@DavidNRockies](https://boards.straightdope.com/u/DavidNRockies)\ **Post date:** [March 29, 2024, 9:41pm UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/292 "2024-03-29T21:41:04Z")
Updated video from that excellent source that @Stranger_On_A_Train used above. It’s more color commentary than revelatory new information, but it’s a good vid. He also kind of refers the viewer to quite a few other relevant maritime channels (none of which I’ve watched), making this a good vid to view at a slightly elevated speed, IMO: [![](https://img.youtube.com/vi/-rxKQ8Tr94s/maxresdefault.jpg "Dali Timeline from Data Recorder in Striking Francis Scott Key Bridge in Baltimore, March 26, 2024") ](https://www.youtube.com/watch?v=-rxKQ8Tr94s) ---
**Author:** ![Magiver](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@Magiver](https://boards.straightdope.com/u/Magiver)\ **Post date:** [March 29, 2024, 10:44pm UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/293 "2024-03-29T22:44:19Z")
> [@Fiendish\_Astronaut](#): > > It looks to me like the protection for the pier and abutment was woefully inadequate for the type of marine traffic that regularly passes under the bridge. I suppose that will be something an enquiry will want to examine. they’ve stated it wouldn’t survive a collision with a cargo ship as far back as 1980. If they didn’t want to spend the money for barriers then they should have used tugs to ensure safe passage. ---
**Author:** ![Magiver](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@Magiver](https://boards.straightdope.com/u/Magiver)\ **Post date:** [March 29, 2024, 10:46pm UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/294 "2024-03-29T22:46:52Z")
> [@EddyTeddyFreddy](#): > > I wonder whether they heard it go behind them, saw it in their rearview mirror, or whether they didn’t even know how close they’d come to a horrible death till they learned the news? Either way, yeh, major shakes. the shock wave of that event would have been felt. ---
**Author:** ![Mama\_Zappa](https://avatars.discourse-cdn.com/v4/letter/m/71e660/32.png) [@Mama\_Zappa](https://boards.straightdope.com/u/Mama_Zappa)\ **Post date:** [March 29, 2024, 11:21pm UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/295 "2024-03-29T23:21:24Z")
> [@Magiver](#): > > the shock wave of that event would have been felt. Maybe, but they were likely on solid ground by the time the bridge fell, and a car’s motion can mask ground shakes. When the earthquake hit the East Coast (back in 2011), my son and I were in the car, when my daughter called, panicking. We felt nothing. The sound, also: I haven’t heard any reports at all as to whether either the impact, or the fall, made a loud noise - I have to assume it did. But between your car’s engine noise, and a tendency to discount distant sounds as “nothing to worry about”, I think I personally would not have noticed it. ---
**Author:** ![Magiver](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@Magiver](https://boards.straightdope.com/u/Magiver)\ **Post date:** [March 30, 2024, 1:24am UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/296 "2024-03-30T01:24:05Z")
> [@DavidNRockies](#): > > Updated video from that excellent source that @Stranger_On_A_Train used above. It’s more color commentary than revelatory new information, but it’s a good vid. Great video. Is there anything out there on the rudder system. That video appears to say it’s based on electrical power but it doesn’t specify how it operates. Is it a rack and pinion system or hydraulic and can it be operated manually? [A century ago they use to operate fairly large swing bridges with a hand crank.](http://industrialscenery.blogspot.com/2020/07/trailb-harmar-bridge-over-muskingum.html). It does’t sound like this is an option in the video. ---
**Author:** ![I\_Love\_Me\_Vol.I](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/i_love_me_vol.i/32/521_2.png) [@I\_Love\_Me\_Vol.I](https://boards.straightdope.com/u/I_Love_Me_Vol.I)\ **Post date:** [March 30, 2024, 8:34am UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/297 "2024-03-30T08:34:37Z")
> [@Dialo\_Malison](#): > > This video suggests a possible explanation for the turn to starboard. > > > [https://www.youtube.com/watch?v=TlIhoxIxM30](https://www.youtube.com/watch?v=TlIhoxIxM30) Can you tell us the possible explanation the video suggests? Thanks. ETA: nevermind… someone else took one for the team and explained. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [March 30, 2024, 8:58am UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/298 "2024-03-30T08:58:24Z")
I saw a video explanation that suggested when the ship restarted its engines (you see the big belch of smoke from the smokestack) that the pilot or engine room put the ship into reverse. This imparts a torque to the ship and will make it want to turn. With no rudder control the ship turned to starboard and we know the rest. Just another possible explanation. I’ll see if I can find the video (it was two ship captains talking so, presumably, they have a clue…I do not though so just speculation). ---
**Author:** ![Dogginit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dogginit/32/16920_2.png) [@Dogginit](https://boards.straightdope.com/u/Dogginit)\ **Post date:** [March 30, 2024, 5:08pm UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/299 "2024-03-30T17:08:53Z")
> [@Magiver](#): > > Is it a rack and pinion system or hydraulic and can it be operated manually? Can’t seem to find the cite I found yesterday, but the steerage was listed as electric/hydraulic - electricity from the generators drive the hydraulic pump for the rudder/steerage. ---
**Author:** ![Magiver](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@Magiver](https://boards.straightdope.com/u/Magiver)\ **Post date:** [March 30, 2024, 6:59pm UTC](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/300 "2024-03-30T18:59:51Z")
> [@Dogginit](#): > > Can’t seem to find the cite I found yesterday, but the steerage was listed as electric/hydraulic - electricity from the generators drive the hydraulic pump for the rudder/steerage. That would seem the simplest. But it begs the question why isn’t there battery backup. Or maybe there is and there’s yet another layer to the accident. I would expect a lot of redundancy on a ship of this size. [Previous page](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372.md?page=14) [Next page](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372.md?page=16)