Baltimore Bridge collapse after ship collision 125

[Tomfh]

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

 

[LionelHutz]

I read that they radioed a Mayday and traffic on the bridge was being stopped or had been stopped by the time of impact. It so, that is an impressive reaction time which saved lives.

You can only deflect, not stop.

It appears the pier withstood the impact. The bow overhang wasn't so kind to the bridge structure on top of the pier though.

 

[FacEngrPE]

A question might be, does the ship plow through the bridge pier or does the pier plow through the ship hull? Both? There is too much inertia to stop it without dumping the energy into breaking and / or deforming something.

 

[TugboatEng]

I'm not totally bought in on fuel contamination but wouldn't rule it out.

The fuel systems on ships consist of storage tanks, a settling tank, and a day tank. Daily fuel transfers are made into the settling tank. Fuel is drawn from the settlers through centrifuges and transferred to the day tank. The centrifuges should manage any water in the fuel.

There has been a high profile case of fuel contamination that caused a total loss of power on the vessel. It was a tugboat Aiviq. The day tank vent was installed in an area of the vessel that could cause it to be submerged. If there is enough water in the fuel to cause an engine to shut down the fuel injection pumps and nozzles are likely to be damaged and require replacement. In the case of Aiviq the injectors had to be airlifted to the tug to get it running again. In videos taken later in the day you can see the Dali is running its generators.

Another fuel related incident that caused a total loss of power that occurred recently was on the Moku Pahu. When making hatch cover gaskets, it's common for engineers to leave the gasket as a solid sheet instead of cutting a ring that covers only the flange. In this instance, the not compressed portion of the gasket fell onto the day tank and then became lodged in the fuel totalizer.

Finally, in environmental control areas ships are required to switch from heavy fuel oils to distillate oils. Loss of power incidents are very common during this transition. Distillate fuels has to be gradually blended in to maintain a viscosity number while the fuel system is simultaneously cooled from ~300-350°F to ambient. This is typically done more than 25 miles offshore and should not factor in to this incident.

 

[SwinnyGG]

A full steel structure going down into the caissons would have given some resistance?

None. That ship was traveling over 7 kts. It's 1000 feet long, 150 feet wide, and weighs in the neighborhood of 160,000 tons. If you want to stop it, you have to do it way before it gets to the caisson.

A question might be, does the ship plow through the bridge pier or does the pier plow through the ship hull? Both? There is too much inertia to stop it without dumping the energy into breaking and / or deforming something.

The answer is both - see elsewhere in the thread for a picture of the bow of the boat.. there is significant damage. I assume there is likely very significant damage to the bulbous bow below the waterline as well.

 

[looslib]

Since most tunnel operators prohibit dangerous cargo from going through them, a new tunnel will not help with traffic. A new bridge must be built to close the 695 beltway loop around the city. Not sure if a tunnel could be built that would survive a terrorist attack if the allowed dangerous cargo to go through them. Of course any terrorist who wanted to blow up a tunnel would not declare their cargo anyway, besides it would be a suicide mission.
The bridge was originally built because it was lower cost then the proposed tunnel solution.

"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli

 

[Brad805]

I think the lack of dolphins or other protection at the piers would be part of the reason USA infrastructure gets a C-.

I doubt designers in the 70's envisioned a modern container ship. Here is an image of a 1977 container ship. I am not much of a mariner, so they could have been larger than this.

 

[Brian Malone]

This site details the changing size of container ships:

https://transportgeography.org/cont...nsportation/evolution-containerships-classes/

Pretty big change from the 1970s to present day.

 

[ALK2415]

I think it is possible that some influential companies have cooperated/colluded to sink this bridge
The fact that the incident is almost impossible to happen
There are many ways that could have stopped the runaway ship, including dropping three anchors, even when the propulsion engines or power generators were not working!

 

[dik]

They have to eliminate the maritime insurance law for all inland shipping, for a start, and have real insurance policies.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Murph 9000]

There are many ways that could have stopped the runaway ship, including dropping three anchors, even when the propulsion engines or power generators were not working!

I think you are vastly overestimating the ability of an anchor (or even 3 of them, if there were enough deckhands available to get them all out in time) to stop 100,000+ tonnes moving at around 4 m/s (8 knots) in maybe 1000 m (I'm guessing the distance available once they knew disaster was likely). Even if the 56,000 hp main engine was working at full power output (and I personally think it might well have been), that wouldn't have been sufficient to pull off a crash stop in that sort of distance.

Have you ever tried to stop a vessel doing 8 knots? The speed seems low compared to other modes of transport, but stopping is difficult (not counting very lightweight craft, i.e. something with a good bit of mass for its size).

The incident is very possible through just ordinary bad luck or poor maintenance. Ships have control, power, and propulsion problems. It's a relatively narrow channel between those bridge piers for that size of ship. People make mistakes (e.g. going full astern, if they did, might turn out to be a critical mistake here, where full ahead might have allowed them to steer away from the pier).

 

[hokie66]

Nothing would have prevented this accident except better, much better, protection for the piers. If the ship grounded on an underwater island before the pier, the channel might be closed for a few days, but nothing like this disaster.

 

[3DDave]

Another recent, though less catastrophic crash, was a ship that had enough overhang at the bow to clean the cargo cranes right off the solidly built dock as it came in at about 30 degrees to the dock.

 

[Brad805]

Reports suggest the anchors were dropped shortly after the incident occurred. We have an M1V1 problem here. So far this seems a genuine accident.

 

[3DDave]

Many similarly configured harbors require ships to have tugs move the ship the entire way past the bridges.

 

[zeusfaber]

When you leave tugs attached to big ships that are steaming fast enough for their steering to be effective, there's a significant risk of girting and sinking the tugs. It might be better economically, but not in terms of Risk to Life.

 

[3DDave]

They don't attach to ships that are steaming fast at all. It's an accepted and widely used practice. It's costly and not economic except it is for safety.

 

[human909]

I think it is possible that some influential companies have cooperated/colluded to sink this bridge
The fact that the incident is almost impossible to happen
There are many ways that could have stopped the runaway ship, including dropping three anchors, even when the propulsion engines or power generators were not working!

ALK. Thanks for continuing to amazing me on how many engineers have no clue about momentum and fail to grasp just how big these ships are. 20 anchors wouldn't have stopped this ship in time! Also anchors don't work the way they do in movies. A small piece of metal dragging across sand isn't going to do much.

 

[Murph 9000]

Yeah, but not just momentum and what can be achieved with an anchor. Until you've tried to stop a 45-50+ foot vessel doing 8 knots, it's difficult to understand the difficulty of doing a crash stop on water. It's got to be at least 45-50 foot waterline length due to the "hull speed" physics, where shorter hulls will have massive additional drag slowing them down by the time they get to 8 knots. You then need to adjust your mental picture from a small craft having probably something like 1-10 hp per tonne, and the ship in this incident having around 0.5 hp per tonne from the main engine (and reversing involves stopping the engine and then restarting the entire engine in reverse, as the crankshaft is essentially directly coupled to the fixed blade propeller).

 

[MTNClimber]

They found 2 of the 6 missing bodies. What a tragedy.

Also analysts are talking insurance claims totaling in the billions of dollars.

 

[enginesrus]

For a large ship like this that doesn't have azipods and bow thrusters, to be allowed to traverse through inland channels with bridges etc. and not under control of tugboats. Someone some where is and was not using much logic. Even most of the highly maneuverable cruise ships have tug boat escorts though I'm not sure what countries do that. I've seen it on cruise ship tv shows.

The excessive smoke from the engines looks like they were throttled up, then backed off. What engine or engines does this ship have? How many props?