Baltimore bridge collapse

[hidetheelephants]

rdjohn said:

BBC News said that there were two pilots aboard. What would they be doing?

Not my field of endevour, but the talking heads are describing it as pilot 1 advises the master who then gives helm & engine commands, pilot 2 doublechecks and deals with radio communications with the tugs etc.

[Abbott]

rdjohn said:

hidetheelephants said:

9/10 problems with DP or autopilots are operator errors; the others are 9/10 sensor FUBARs. The remaining 1% is WTF ghost in the machine st.

BBC News said that there were two pilots aboard. What would they be doing?

There was an early report that said there were 2 pilots on board, one for the Port area and another for the river leading to the port.
I believe the pilots bring local knowledge on currents, hazards etc

[ChocolateFrog]

I'm surprised the stanchions/pontoons were not built to withstand a boat strike, even one weighing 50000 tons or whatever this one weighed.

[vaud]

ChocolateFrog said:

I'm surprised the stanchions/pontoons were not built to withstand a boat strike, even one weighing 50000 tons or whatever this one weighed.

The design massively predates these super-container ships.

[MiniMan64]

ChocolateFrog said:

I'm surprised the stanchions/pontoons were not built to withstand a boat strike, even one weighing 50000 tons or whatever this one weighed.

It’s gonna have to be pretty fking big to withstand a hit from one of those beasts.

[Vipers]

Benni said:

On german radio, it was mentioned that the engine troubles/shutdowns were a result of "polluted fuel".

Early days, investigations have just started, how on earth can they say polluted fields.

[Vipers]

hidetheelephants said:

9/10 problems with DP or autopilots are operator errors; the others are 9/10 sensor FUBARs. The remaining 1% is WTF ghost in the machine st.

Can’t comment, but I do know this one was unexplained and never identified. There is a DP report published by IMCA based on all reported DP incident, not that am about to plough through it.

[skwdenyer]

ChocolateFrog said:

I'm surprised the stanchions/pontoons were not built to withstand a boat strike, even one weighing 50000 tons or whatever this one weighed.

If the ship weighed 100kT, was travelling at 9 knots, and took 5 seconds to stop during the impact, it imparted a force of around 800MN to the bridge for 5 seconds.

9 knots is around 1m/s.

It is certainly possible to create a defence against such a load. It will essentially be a concrete artificial island. It isn’t routinely done for obvious reasons. In this case it would in essence remove the channel for shipping.

The best defence is a very wide span bridge, which I suspect will be the replacement here. It may then be feasible to reinforce a couple of locations to the sides as a hedge against a second lightning strike.

[hidetheelephants]

skwdenyer said:

ChocolateFrog said:

I'm surprised the stanchions/pontoons were not built to withstand a boat strike, even one weighing 50000 tons or whatever this one weighed.

If the ship weighed 100kT, was travelling at 9 knots, and took 5 seconds to stop during the impact, it imparted a force of around 800MN to the bridge for 5 seconds.

9 knots is around 1m/s.

It is certainly possible to create a defence against such a load. It will essentially be a concrete artificial island. It isn’t routinely done for obvious reasons. In this case it would in essence remove the channel for shipping.

The best defence is a very wide span bridge, which I suspect will be the replacement here. It may then be feasible to reinforce a couple of locations to the sides as a hedge against a second lightning strike.

Not in this case, the dredged channel is 200 yards wide, the gap between the bridge pylon bases is 360 yards, there is plenty of room; in any case there's no need to be able to absorb 10kts/100kt energy inside the gap, only from the likely approaches. There are bridges and other high value infrastructure of similar age that have had protection retrofitted, it's not been done here because it costs money and politicians are human, they'd rather spend the millions building something shiny than on a ship crash barrier for a bridge.

[fatboy18]

Wonder if they will reach out to Bridge designers such as Sir Norman Foster to come up with a new Bridge design?

[aeropilot]

fatboy18 said:

Wonder if they will reach out to Bridge designers such as Sir Norman Foster to come up with a new Bridge design?

Not if they've got any sense......

[BrettMRC]

Stick Legs said:

BrettMRC said:

Benni said:

On german radio, it was mentioned that the engine troubles/shutdowns were a result of "polluted fuel",
can anyone here confirm that, has it been mentioned elsewhere ?
When did this ship get the latest refuelling ?
I guess that there are fuel samples collected from everything that is pumped into the tank(s) ?
Is polluted / diluted / "fecked around with" fuel an issue in global shipping at all ?

A two stroke diesel, (which I assume this is) will run on pretty much anything that it can get through the nozzle/injector - so I doubt it's a fuel quality issue...

Whilst true that HFO is pretty thick they would have almost certainly been on MGO leaving port.

This is a purifier on one ship I was on after the fuel was supplied off spec & waxed.




Could be possible if ambient temperature was low enough & the system are cold…

Bloody hell

[AW111]

skwdenyer said:

If the ship weighed 100kT, was travelling at 9 knots, and took 5 seconds to stop during the impact, it imparted a force of around 800MN to the bridge for 5 seconds.

9 knots is around 1m/s.

It is certainly possible to create a defence against such a load. It will essentially be a concrete artificial island. It isn’t routinely done for obvious reasons. In this case it would in essence remove the channel for shipping.

The best defence is a very wide span bridge, which I suspect will be the replacement here. It may then be feasible to reinforce a couple of locations to the sides as a hedge against a second lightning strike.

9 knots is actually 4.6 m/s...

[Hill92]

A similar case in Florida:

https://en.wikipedia.org/wiki/Sunshine_Skyway_Brid...

They made very sure the replacement bridge was protected:

[rdjohn]

hidetheelephants said:

rdjohn said:

BBC News said that there were two pilots aboard. What would they be doing?

Not my field of endevour, but the talking heads are describing it as pilot 1 advises the master who then gives helm & engine commands, pilot 2 doublechecks and deals with radio communications with the tugs etc.

Two fairly obvious influencing factors might be.

Keep the tugs attached and operational until potential obstructions have been passed.

The supporting pier was constructed on a circular cofferdam. A more thoughtful design would be a greatly elongated teardrop both upstream and downstream of the pier effectively forcing a glancing blow.

Their overall dimensions also need to be sufficient to ensure no ship could get close to disturbing the relatively flimsy steel design that cannot withstand a severe lateral impact.

It brings to mind the collapse of the twin towers on 911. They were designed to withstand a glancing blow from an aircraft wing. Like this bridge design, no one envisaged the risk of anything bigger.

[hidetheelephants]

When the bridge was designed a big ship was 30k tonnes.

[fatboy18]

aeropilot said:

fatboy18 said:

Wonder if they will reach out to Bridge designers such as Sir Norman Foster to come up with a new Bridge design?

Not if they've got any sense......

[MBBlat]

Big question, why weren’t tugs used until the ship cleared the bridge?
https://youtu.be/R4AuGZIhJ_c?si=U0_wztzqIO8tV4Ha

[Stick Legs]

MBBlat said:

Big question, why weren’t tugs used until the ship cleared the bridge?
https://youtu.be/R4AuGZIhJ_c?si=U0_wztzqIO8tV4Ha

Escort towage is a thing in lots of ports.

Probably soon to come to Baltimore.

Maritime safety, like aviation safety, moves forward one disaster at a time.

[e600]

After a similar incident 40 years ago in Florida the replacement bridge supports were protected by concrete islands. I wonder why this was not considered SOP for all such bridges given the potential for severe consequences if struck.