South Korean ferry MV Sewol flips, 1/2 sunk in shallows, people trapped.....

Discussion in 'Stability' started by Squidly-Diddly, Apr 17, 2014.

  1. jehardiman
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    jehardiman Senior Member

    It is not just second and third world engineering that is failing...check out where Airbus said the pilot moved the rudder too much...American Airlines Flight 587...http://www.ntsb.gov/doclib/reports/2004/AAR0404.pdf

    Abstract: This report explains the accident involving American Airlines flight 587, an Airbus
    Industrie A300-605R, N14053, which crashed into a residential area of Belle Harbor, New York,
    following the in-flight separation of the airplane’s vertical stabilizer and rudder. The safety issues
    discussed in this report focus on characteristics of the A300-600 rudder control system design,
    A300-600 rudder pedal inputs at high airspeeds, aircraft-pilot coupling, flight operations at or
    below an airplane’s design maneuvering speed, and upset recovery training programs. Safety
    recommendations concerning these issues are addressed to the Federal Aviation Administration
    and the Direction Général de l’Aviation Civile.
    The
     
    Last edited: Oct 4, 2014
  2. rwatson
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    rwatson Senior Member

    How is this similar ?

    The Airbus didn't have extra illegal passenger accommodation tacked on, critical ballast removed, and several over limit tonnes of heavy non-secured cargo.
     
  3. jehardiman
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    jehardiman Senior Member

    You are correct, what Airbus did was much worse. They deliberately designed an aircraft that would structurally fail under allowable pilot rudder input in the normal flight envelope.
     
  4. powerabout
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    powerabout Senior Member

    AA also had to change their flight manual on how to fly as airbus proved they had been training their pilots wrongly.
     
  5. Pascal Warin
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    Pascal Warin Junior Member

    Greed ! Greed ! Greed !
    That is the core of the story like in the "Herald of Free Entreprise" case.
     
  6. ImaginaryNumber
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    ImaginaryNumber Imaginary Member

    South Korea to open bids for Sewol ferry salvage | 7 News
     
  7. ImaginaryNumber
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    ImaginaryNumber Imaginary Member

    South Korea chooses company to lift sunken Sewol ferry | CTV News
     
  8. Sailor Alan
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    Sailor Alan Senior Member

    Thank you Imaginary Number.

    Raising a small ship like this, especially from depth poses problems. If I understand the tidal situation, this will be a real issue controlling things at that depth. Visibility is reported poor as well.

    Hard to tell exactly what the options really mean, or are.

    Putting cables under the hull, and lifting equally on both sides is perhaps the most popular. Unfortunately it needs great skill and persistence to cut/tunnel the necessary holes or slots in the seabed under the hull, usually with divers, in attendance at least. At 130+ft, diving is difficult, and has severe time constraints. Then there is the issue of keeping the cables exactly where they need to stay, without having them slipping, laterally and/or along the hull. This is routinely achieved using a welded steel frame suspended just above the sunken hull, making the steel wire rope strops as short as possible.

    Attaching cables to the hull, using holes and attachments, or welding, assumes plating is strong enough, and there are enough of them. They are generally easier to attach, and stay where they are put. Given enough cables (actually attachments, to distribute the load), this is straight forward. Attaching these to a welded frame above the sunken vessel really requires every cable to carry the same load, not necessarily easy underwater, though modern technology allows load shearing by remote control winches.

    I would favor this second option as being more amicable to remote (unmanned) operation, and far less dangerous for divers. Tunneling under a steel hull at 130' can be no fun at all.

    Other options are; Ping pong balls, or similar, injected in the hull might work. Blowing air in sometimes works, but assumes the hull is still integral, the deck is attached to the hull well enough, and has limited/controllable leaks. Chains do not seem to work.

    Assuming a welded frame structure is attached by cables just above the vessels hull, would air filled lifting bags be better, or winching from the surface, given the tides and depth? The tides might help the initial 'unsticking' of the hull, but it would need serious power to control the then 'free' submerged hull assembly.
     
  9. ImaginaryNumber
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    ImaginaryNumber Imaginary Member

    South Korea begins salvage operation to lift Sewol ferry two years after vessel sank | The Japan Times
    .
    [​IMG]
     
  10. ImaginaryNumber
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    ImaginaryNumber Imaginary Member

    Sewol Salvage Pushed Back Due to Complications | Maritime Executive
     
  11. ImaginaryNumber
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    ImaginaryNumber Imaginary Member

    Riskiest Step in Sewol Salvage Completed | Maritime Executive
     
  12. ImaginaryNumber
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    ImaginaryNumber Imaginary Member

  13. ImaginaryNumber
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    ImaginaryNumber Imaginary Member

    Everything is set to hoist sunken Sewol ferry | Korea Times

    see also:
    http://www.koreaherald.com/view.php?ud=20170319000260

    [​IMG]
    A semi-submersible vessel will carry the sunken Sewol to a port in Mokpo
     
  14. ImaginaryNumber
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    ImaginaryNumber Imaginary Member

    After two years, Sewol ferry is successfully lifted off the ocean floor | Korea JoongAng Daily
    This link shows animated cartoons of lifting process:
    http://www.cnn.com/2017/03/21/asia/south-korea-sewol-ferry/
     

  15. ImaginaryNumber
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    ImaginaryNumber Imaginary Member

    SEWOL has been raised

    [​IMG]

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    [​IMG]
    http://koreajoongangdaily.joins.com....aspx?aid=3031332&cloc=joongangdaily|home|top

    http://www.koreaherald.com/view.php?ud=20170322000923

    https://thecourier.co.uk/news/uk-wo...-ferry-in-which-304-died-lifted-from-the-sea/
     
    Last edited: Mar 25, 2017
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