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Francise scott key bridge. Could it be remade immune to damage?

Arugela

By Arugela
in Science & Spaceflight

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darthgently

darthgently

Posted
Posted (edited)
  On 3/31/2024 at 5:07 AM, kerbiloid said:

Big tunnels for ships.

Put the river in a pipe, and let the ships run inside. Then no bridges are needed.

Like this one, but bigger.
https://en.wikipedia.org/wiki/Neglinnaya_(river)

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Absolutely not.  Remember the Suez Canal fiasco?  A ship tunnel would make the plumber's bill even more astronomical

What about dummy pilings, or shoals, upstream from the real ones to act as fenders?  Could be aggregated from coffee grounds, eggshells, and plastic Walmart bags

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Kerbart

Kerbart

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  On 3/27/2024 at 2:30 AM, Nuke said:

(these kinds of vessels tend to have electric omnidirectional thrusters, as a rudder is slow on a ship of this size, titanic effect

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Cruise ships do. They enter ports on a nearly daily basis and need to be maneuverable. Container ships, on the other hand, need to be economic; that's the reason they're so large for starters. So it's nearly always single screw, direct drive powered by a two-stroke Diesel engine that rivals power plants in thermal efficiency. This is one of the reasons 50" TV's sell for less than $250, as the transport cost for SEA to the US east coast (nearly 14,000 nautical miles) is nearly negligible.

Once the engine stops there's not enough water flowing over the rudder to be effective; even with the rudder operable after backup systems came online. Surely tugs would have been able to stop the ship, but you'd need 4 or 6 tugs, and what for, a contingency that hasn't happened for decades and decades? Your TV would cost $50 more and ocean shipping is enough of a cutthroat business that shippers would pick a cheaper carrier instead, so no one does that.

The crew did everything in their power after power went out:

  • Drop anchor — which didn't do anything due to the amount of silt on the channel floor.
  • Contact shore immediately to warn about a possible allision with the bridge. This saved countless lives.
  • Hope for the best as they're now passengers on this ride. Probably desperately trying to get the engine going again.

The power failure will surely be one of the things the NTSB will focus on.

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kerbiloid

kerbiloid

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Everything useful had been invented long ago.

  Reveal hidden contents

 

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mikegarrison

mikegarrison

Posted
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  On 3/30/2024 at 7:09 PM, Kerbart said:

The Jones Act prevents unloading cargo on board of foreign vessels in US ports that was loaded from US ports. The FMC really doesn't care what your circumstances are, you will need to get an extension for that. Last time a Jones Act extension was granted, if memory serves me right, was after hurricane Sandy to allow repositioning of empty containers, just to give an idea on how rare those occasions are. Now, I don't think it will be an issue in this case, but it does need to be cleared first and it's not an insignificant administrative hurdle.

Because of laws that protect US Maritime interests.

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Most countries have laws about cabotage (picking up people or cargo inside of a country and delivering them to another place in that same country). Typically they protect their own industries by not allowing foreign operators to do that. https://en.wikipedia.org/wiki/Cabotage

In air travel, the Chicago Convention defines the "freedoms of the air" that include these concepts. https://en.wikipedia.org/wiki/Freedoms_of_the_air

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darthgently

darthgently

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Posted
  On 4/2/2024 at 4:06 PM, farmerben said:

The longest span of the Key bridge was 366m.  Current state of the art suspension bridges can go to 2000m.  Make the pillars 5 times as far apart and then there is plenty of room to steer and to run aground before hitting a pillar.

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I wondered why the pylons seemed so close together.  I would bet that many of the local captains, the port authority staff, the local CG, and many other pros in the area have been concerned about the design and age of that bridge for decades given its position in a critical shipping channel and it has probably come up in conversations many, many times that it needed to be replaced. 

I guess either be relieved that it will now be replaced, or be careful what you wish for

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mikegarrison

mikegarrison

Posted
Posted
  On 4/2/2024 at 4:06 PM, farmerben said:

The longest span of the Key bridge was 366m.  Current state of the art suspension bridges can go to 2000m.  Make the pillars 5 times as far apart and then there is plenty of room to steer and to run aground before hitting a pillar.

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Longer spans are more expensive. They are generally only used when they are needed.

There is a lot that goes into bridge design in this respect, but to the best of my knowledge the key factors are usually the available support. If the water is shallow and the bedrock is solid, they use supports. If the water is too deep or there is no solid ground, they use longer spans. (Or where I live, they sometimes use floating pontoon bridges.)

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