Here is Starbuckâs summary of Concordiaâs journey, from the time she made contact with an underwater part of Isola del Giglio to the time she settled on a rocky shelf a bit further up the coast:
[QUOTE=Starbuck1;62185]So our stability/list/capsize scenario at the moment is: Due to a badly done turn on a close pass-by, the port side is ripped open for 150â, opening 5 WT compartments to the sea. As the ship coasts to a stop, over the next 30 minutes, at first there is a port list due to loss of buoyancy on the port side, but it gradually returns to an even keel as the flooding spreads across the full beam of the ship in 5-20 minutes. (Is there any other information on timing of changes in list?). The ship is steered in a slowing gradual turn to the right, past the eye of the wind when it finally stops, we guess on a roughly even keel.
The 12kt NNE wind pivots the ship around the flooded and deeper drafted stern until the wind is on the port quarter and, while the ship is gradually flooding, it drifts back toward Porto Giglio. The wind pressure of the NNE wind on 100,000 square feet of the port side heels the ship slightly to starboard. (Is 40-60 tons of wind pressure 50â high really sufficient to do this?) (Has the flooding in the ship reached a point where it will loll significantly with modest pressure?) This causes the flooding in the ship to move to starboard and gradually amplify the overtopping of the remaining watertight compartments onto the starboard side. Now the progressive flooding is dumping the water into the starboard side of each compartment as it overtops. As the ship runs around, aft first, the now lower starboard side touches ground at 0.5 knots (but if aft hit first wouldnât it kill the speed while the ship pivots on the stern to its semi-final alignment?). The captain drops the anchors to hold it in place and finally calls Mayday and begins to abandon ship. Momentum is zero.
So it is aground with a 20Âș? starboard list, lights on, about 1 deck of hull showing below the boat deck, launching the lifeboats. The list is gradually steepening as the hull fills. Within a half hour, the water is up to the boat deck, the list is up to about 30Âș but most/all of the starboard boats are away now and a few are nosed into the ship to pick up more passengers. The port side boat launching has problems due to the list, but eventually all but 3 are launched.
So far the arguments have all been based on no damage to the starboard side adding to the list, and no asymmetric loading of internal tankage or transfers of ballast/counterflooding by the ER crew since we have no data on this, although all three are possible.
(see below for last paragraph)[/QUOTE]
I donât know if anyone else has come across this website?
http://www.qps.nl/display/qastor/2012/01/17/20120117_stranding
My internet is rather slow at the moment, so I have only looked at the last video, a 3-D animation of a little model âCosta Concordiaâ doing here thing with additional info such as depth of water, course heading and so on. If this animation is at all accurate, and for arguments sake lets say it is, well I think it bears out Starbuckâs description rather nicely.
[QUOTE=Starbuck1;62185]
(Starbuckâs last paragraph:)
Hereâs where it gets messy. Even though the list is modest, 20-30Âș, and the starboard bilge is aground (?), the ship continues to roll to starboard until by 2400 or 0100, it is on its side with 300 or so survivors walking off along ropes or ladders on the side of the ship. The main wound is fully exposed now. (Would it really be so top-heavy that only a 20-30Âș list would be past the point of no return? Why didnât it settle back to port, pivoting on the starboard bilge rather than going all the way to starboard?). A rock under the hull? Asymmetric flooding/buoyancy? Flooding from the boat deck level (many openings open) on the starboard side of middle decks rather than flooding all the way to the bilges increasing the height and starboard side bias of the CG ? hmm.[/QUOTE]
What is interesting to me is that after, I guess, the ship has grounded on the rocky plateau, right at the end of the video, the shipâs bow continues to fall away to stbd. while the stern remains stationary. From this I deduce that yes, she has indeed got her stern stuck on the rock and the forward two thirds/three quarters of her is free floating â but also, she is free to pivot on her stern, a bit as though she is balanced on a rock outcrop. Even if she is on a fairly blunt rocky outcrop, or even on flat sloping rock, I think because she is able to pivot freely left and right, the point of contact could be fairly well aft â just where the lines of the ship narrow quite rapidly to form the underwater pinched shape so as to have a nice flow of water pass her propeller when she is steaming along under normal conditions. But the pinching in of the underwater shape of the hull also means that the flat area of the shipâs bottom, the further aft you go the narrower it gets, and any point of contact would be nearer the C/L. (Remember she trimmed by the stern by several meters). Therefore this could mean that she is also free to list, lean, loll or roll left or right (not just pivot in the horizontal plane), to any external forces with out much resistance â and with the assistance of free surface water flooding in as well. The light breeze on her vast superstructure may have been just enough to cause her to flop to stbd., a few degrees at first but increasing in time with continuous and steady flooding until she was all the way over. The stbd. bilge didnât prevent the capsize because it was never properly in contact with the sea bottom (???).