Simulating Costa Concordia

Discussion in 'Boat Design' started by APP, Jan 17, 2012.

  1. peterAustralia
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    peterAustralia Senior Member

    I read somewhere on another site, that using satellite tracking of the same ship on previous occasions, but with different captain, the ship had passed by the exact same spot. Other cruise ships always stayed 2000m out or so

    So was the captain following instructions, or did he have a verbal go ahead to sail so close to the shore.

    If on previous occasions the ship had sailed so close to shore, teh owners would have seen the satellite tracking information and given explicit instructions not to do this. However they did not. Going close gives the passengers a better view

    So based on that information.. it does not look as though the captain was entirely at fault.

    I got this information from one of teh 'friends' of uglyships.com. If desperate I could retrieve teh page again
     
  2. BPL
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    BPL Senior Member

    If the Costa Concordia could be modeled and simulated it would be interesting to look at:

    1.) what uneven bottom slopes would cause the ship to tip over as it did

    2.) what structural cost would have been necessary to prevent sinking from the same collision

    3.) what would have happened with the amount of damage if not grounded the way the ship was
     
  3. aranda1984
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    aranda1984 aranda1984

    Children and ladies first...

    Not this time!

    Last night, I watched a special report on this accident. (Costa Concordia)
    The surviving people said in the dark there was a mad dash and it was everybody for themselves!

    Survival of the fittest, I guess!

    Strong men stumping over handicapped old ladies and children.

    They also stated that some 98% of first class , a bit less of second class and a large percentage of third class women also survived the sinking of the Titanic.
    Hmm.. Is this saying that the feminist have finally achieved equality, or chivalry is dead?
    ... Don't answer this!

    Regards,

    Stephen
     
  4. APP
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    APP Junior Member

    Right.
    First of all is it possible to model the vessel? Based on the data available (see above post #1) is it possible for an expert to guess the LCG, VCG and Cp (prismatic coeff.) and/or Cb of Concordia?

    Regards
    APP
     
  5. IEWinkle
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    IEWinkle Retired Naval Architect

    Costa Concordia Data

    Hi,

    I am grateful that you have found a source for the Displacment of this vessel. However, I must correct the Freeboard quoted to 14.18m as given in the vessel's Wikipedia entry together with an Lpp of 247.4m. This allows an estimate of its Block Coefficient as 0.696 and approximation of its KB at 4.5m and BMt at 15.6m. With a KMt of around 20.1m it is fair to assume that the KG of the vessel lies between 18 and 19m.

    However, with an openning of some 50m in the hull (at least 20% of the waterplane will have been lost), the redistribution of buoyancy would result in a substantial reduction in BMt as the vessel sinks and trims by the stern which will only be partially compensated by the small rise in KB. It is to be expected therefore that the vessel is likely to become unstable and loll. Initially this seems to have been to port, but as the 180 degree turn occurred, it seems to have flipped over to starboard and remained like that until it run aground on the rocks. At that time news photos clearly show the aft starboard corner of the bulkhead deck substantially under water which is likely to result in progressive flooding of the lower passenger deck which together with further breaches of the hull around the grounding point would result in the eventual total capsize.

    If the freeboard deck had enclosed the lower two passenger decks, the vessel would have survived afloat even in a lolled state and could have anchored off to discharge the passengers. Admitedly this would have annoyed passengers who would have many more bulkheads in their way in moving around the decks, but the ship would have been much safer.
     
    Last edited: Jan 28, 2012
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  6. APP
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    APP Junior Member

    Thanks. Very professional. By the way, if you have time, can you analyse in detail the meaning of your phrase "If the freeboard deck had enclosed the lower two passenger decks, the vessel would have survived afloat.."
    It seems this could be a key issue here as far as safety is concerned.

    Regards
    APP
     
  7. aranda1984
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    aranda1984 aranda1984

  8. IEWinkle
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    IEWinkle Retired Naval Architect

    The best way to prevent progressive flooding is to ensure greater reserve buoyancy though increased freeboard and that implies full transverse subdivision of the additional decks below the new bulkhead deck.
     
  9. BPL
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    BPL Senior Member

    "Why did the ship roll on its starboard side, when the gash in vessel was on the port?"
    "The internal architecture of cruise ships is so complex that even with the same effects being accounted for in say experiments, computer simulations or indeed in real life accidents, we could potentially see a different outcome every time we simulate the accident," Vassalos, professor of maritime safety at Britain's University of Strathclyde, says.

    http://travel.usatoday.com/cruises/...osta-Concordia-disaster/52808568/1?csp=34news
     
  10. Angélique
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    Angélique aka Angel (only by name)

    The ship is resting on the bottom, seems to me that the rock bottom profile there on spot forced her into her current position.

    To which side and how much was she listed just before grounding there . . ?

    Cheers,
    Angel
     
  11. naval ark
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    naval ark Member

    There's a good recreation of the vessel's movements here.

    It looks like there was an all-out power (propulsion) failure after initial impact, as the ship continually loses speed, tries to turn to stbd with whatever way she has on but then drifts back towards the outcrop.

    I haven't seen any details of the prevailing weather, but at a guess I would think it more likely to have been blown down with wind out of NE vs. swept with the current.

    Stability must've been marginal and even the slightest upthrust upon contact (well known during grounding and drydocking) coupled with the increased wind force (once the vessel stops making leeway) was maybe enough to knock her over.

    Just my guess, Angelique has a good point, but I'm not sure this vessel would be able to maintain an equilibrium angle >80 deg.
     
  12. Angélique
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    Angélique aka Angel (only by name)

    Even at the point where she is now she's metastable, don't know what she tends to do, slide down the slope, or fall over further to starboard, or both . . . ? ?

    Here's a week old quote about this from another thread with the knowledge from the news at that time, maybe more bottom info has come up . . ?

    (click on [​IMG] in the quote if you want to go to that thread & post)
     
  13. IEWinkle
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    IEWinkle Retired Naval Architect

    The explanation is in my post 20 above as the vessel has developed initial instability and in consequence 'lolls' initially to port and then flips to starboard at the time of its final turn. There is little complexity in the machinery space of such a vessel with two compartments housing 6 diesel generators.
     
    Last edited: Feb 2, 2012
  14. smartbight
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    smartbight Naval Architect

    Large windage Area. Larger than NIMITZ for half the displacement.

    "Why did the ship roll on its starboard side, when the gash in vessel was on the port?"

    At the start of the final 180 deg turn the list was ~ 20 deg port. During the turn, the reported 12 knot NE wind caught the large transverse windage area of the vessel and flipped her to the stbd side.
    We will have to calculate that very large force when we run some damage conditions.
    This same wind explains why the stabilizers were extended upon their departure from Rome. They are needed to dampen the substantial roll motion experienced by this type of 'tender' ship with a GM around ~1.5 ft.
     

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  15. smartbight
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    smartbight Naval Architect

    I meant,

    'tender' ship with a GM around ~1.5 meter, not feet
     
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