Shocking crane barge accident

Discussion in 'All Things Boats & Boating' started by waikikin, Aug 4, 2015.

  1. waikikin
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    waikikin Senior Member

  2. Angélique
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    Angélique aka Angel (only by name)

    From the Random Picture Thread: (below first quote was posted one minute before above opening post, so they kinda cross posted)

     
  3. Angélique
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    Angélique aka Angel (only by name)

    Looks like the "Pontoon Effect" which is the tendency of pontoons to capsize when a heavy load with a high centre of gravity is placed on it . . :idea:
     
  4. Angélique
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    Angélique aka Angel (only by name)

    I think ;), the cause of this accident is that the "pontoon effect" is not on the Dutch Wikipedia pontoon page, the English Wikipedia pontoon page links to the "pontoon effect".

    Now they have a full scale investigation going on to find out, which will take months they say. Dutch media also says all parties involved were very experienced see bottom :rolleyes:
     
  5. Angélique
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    Angélique aka Angel (only by name)

    Did some research in the YouTube archives . . .

    Above accident was with the new Juliana Bridge in the Dutch town of Alphen aan den Rijn.

    In 2011 the old Juliana Bridge was temporarily removed for repairs of the pivoting points.

    An other crane company then used three cranes, two on a solid place on both sides of the bridge, and one on a pontoon.


    Hoisting starts at 2:29. A rusted away hole in a pivoting point gusset plate is visible at 3:23. Both pivoting point mounts were in very bad shape, which was the reason for the repairs.

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    At 0:51 there's a lady looking through a hole in a pivoting point gusset plate.
     
  6. Angélique
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    Angélique aka Angel (only by name)

    Video made about one hour before the accident, showing a lot of details, looks like it's made by a drone.


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    The accident . . . (same as in post #1)

     
  7. Angélique
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    Angélique aka Angel (only by name)

  8. DCockey
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    DCockey Senior Member

    I am skeptical that the "pontoon effect" was the cause of the accident.

    In the video of the accident https://www.youtube.com/watch?v=8_nTLIuk6Hk#t=13 the crane further from the camera and the suspended bridge section start to move more quickly at about 1:04 witht he decks of the pontoons still above the water. The deck of the further pontoon remains above water until about 1:08 and at that time the crane and bridge section are out of control.
     
  9. Angélique
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    Angélique aka Angel (only by name)

  10. Angélique
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    Angélique aka Angel (only by name)

    My interpretation is that the farthest pontoon suffered from the "pontoon effect" first, and then the crane on that pontoon took the crane on the nearest pontoon along in its fall.
     
  11. Angélique
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    Angélique aka Angel (only by name)

    My interpretation of the faster movement of the farthest crane is that's because that crane had to move more in order to make a 90° turn for the bridge deck, in order to get it into place. I think while doing so the farthest pontoon suffered from the "pontoon effect" first.
     
  12. Angélique
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    Angélique aka Angel (only by name)

    Well, I'm not sure why the 90° turn was, but it was made during the second half of the first minute of the video, at first there was no panic visible among anyone of the visible crew, so the turn seems to be a planned move. Or the turn was caused by the by the "pontoon effect" of the farthest pontoon already while the visible crew on the nearest pontoon didn't notice yet.
     
    Last edited: Aug 10, 2015
  13. DCockey
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    DCockey Senior Member

    "Pontoon effect" occurs when the deck starts to submerge and the waterline area rapidly decreases. The deck of the farthest pontoon is above water until about 1:08 and at that time the accident is already underway.
     
  14. Angélique
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    Angélique aka Angel (only by name)

    That's right David, that's why I said in post #3: ‘‘ Looks like the "Pontoon Effect" ’’ and not ‘‘ It is the "Pontoon Effect" ’’

    I think real cause of the accident is mentioned in the quote in post #3, and that this cause is related to the "pontoon effect" by the heavy load with a high centre of gravity which is also the cause of the "pontoon effect".
     
    Last edited: Aug 10, 2015

  15. jehardiman
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    jehardiman Senior Member

    Deck edge submergence is not a requirement of the "pontoon effect". It happens when the righting moment goes negative. This occurs when effective CG (generally with wind and suspended loads but no free surface effect) passes outboard the CB and GM goes negative, both which can occur without deck edge submergence, cf the MV Stellamare.

    FWIW, when I first saw the video, my first impression was that the far crane's outrigger float punched through the deck.
     
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