IEWinkle
Retired Naval Architect
- Joined
- Jan 25, 2012
- Messages
- 97
- Reaction score
- 15
- Location
- Glasgow
I am happy to see that progressive flooding through watertight (WT) doors aft is discussed as being a (the proximate?) cause of the following capsize.
Assuming watertight engine compartments #4, 5, 6 and 7 were upflooded due to the side contact damages, what is the new draft and trim on stern?
Assume that deck #4 is the bulkhead deck and that deck #5 has the mooring deck aft and that the space between decks #4 and 6 is a weathertight superstructure, would deck #5 aft come below water due to upflooding of compartments #4-7. I doubt it. I think deck #5 aft was above waterline after the contact and that the vessel was floating and stable upright. So no down-flooding via doors on the mooring deck is expected.
Thus, the only possibility that ship trims more on the stern is actually progressive flooding through open W/T doors aft of the engine room (compartment #4).
Did such doors exist?
What do compartments #2 and 1 contain? On deck #2? Engine stores? If so I expect W/T doors to be fitted there (and that they should have been closed at sea). On decks #3 and 4? Ship stores? With W/T doors (that are not allowed by SOLAS!)? Actually it doesn't matter because the decks are not watertight and open W/T doors on deck #2 will cause compartments #2 and 1 to fill up (deck #5 aft will be submerged) while GM and GZ becomes 0 = capsize. It will be interesting to see what the Italian Accident Investigation Commission will find.
The drafts are quoted in my post 57 on http://www.boatdesign.net/forums/boat-design/simulating-costa-concordia-41365-4.html based on the night-time shot of the vessel as is reached the shore. This gives about 2 m of freeboard on the centreline of the bulkhead (mooring) deck aft which becomes about -2.2 m at the starboard corner due to the 13.2 degree list - leading to progressive flooding through any sounding/vent pipes in that area by this stage. The analysis in post 58 following suggests some of the possibilities for flooding to get to this stage. Which if any doors were left open will have to wait until a proper examination of the vessel is undertaken. If there was no flooding of structures outboard of the engine casings above the 7.2 m deck level the vessel would have survived 5 compartment flooding without significant list. Perhaps this is what led to the Master's indecisiveness over evacuation? SOLAS compartmentation would assume flooding thoughout the depth of the vessel including the double bottom and side decks above 7.2 m. Under these assumptions she would be lucky to survive 3 compartment damage!
See post 294 below!
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