Simulating Costa Concordia

[nettersheim]

Great job, thanks for this profile.

 

[Martijn_vE]

v 2.6 will show outboard profile background image as seen on screen dump.
Bilge radius is around 2.2 m amidships as per photo ? (doesn't look like a true radius).

The bulb shape on the photo's differs significantly from the one in the FREE!ship model. Also when looking at the pictures, and in particular the one below, the frames around the aft bow thruster seems much more straight then the ones in the model. It looks like it still needs some work.
However without more accurate drawings any calculation will probably be not much more then (educated) guess work.
On the other hand if you can get your hand on a lines plan, which is unlikely, or a general arrangement which shows several deck plans below/above the waterline then the results will be much more useful.

 

[smartbight]

It looks like it still needs some work.

Thanks for taking a look.
With all the pictures and data available we should be able to model a set of lines close to the original. We just need to find someone (NA student ?) who has the time to 'hammer' the plating into the right shape.

 

[IEWinkle]

We used the brochure you provided and blew it up to scale. The bulkheads are the ones shown on the brochure. The spacings shown do not give us a constant frame length yet. If you can mark up the drawing or write down the corrections needed, we can have it revised.

Sorry for delay in responding but been away for 3 days - also insufficient means at my disposal to sketch on your blow up. However, I have a number of comments which may help. Your 'Damaged WL Port' as shown is in fact the projection of the waterline onto the centreline giving the average draft aft of 12.05m at AP. The two inclined waterlines Port and Starboard should be parallel and offset from this one by about 4.16 m. In this case the starboard one should be the deeper and should correspond to the night-time image shown in my post. All my dimensions were worked out from the cabin plan on Deck 1 which shows a set of identical cabins along the length with lengths which scale to almost exactly 2900 mm - hence the web spacing (note this is clearly seen in the exposed damaged area as 4 frame spaces). Once you get into the after peak area the frame spacing will reduce to 600 mm as will also be the case in the area of compartments forward of compartment 14. However, in the main body over the damaged spaces it should be constant at 725 mm. All compartment lengths (4 to 14) should therefore be a multiple of 725 mm. My longitudinal locations were deduced from the Deck 1 plan observing that steel bulkheads appear between groups of 4 and 6 cabin multiples several corresponding to those around the two main access trunks (stairwells). My other observation was that the lifeboat bays are set between vertical pillars which will correspond to web spaces/bulkheads below and that these lie between corresponding cabin windows. Counting cabin windows along the length in sets of 4, 5 & 6 give the distances between the visible pillars and looking carefully at the lifeboat falls on the port side which drape vertically down the hull pinpoints within about 0.5 m where the damage begins and ends. The lifeboat locations shown on the deck 4 plan together with the cabin arrangement on Deck 1 can also be tied into the main bulkhead locations of the two stairwells - 4 cabins at the aft end (above comp 3/4)and 5 cabins forward (comp 8). This suggests 11600 mm for comps 3/4 rather than 11634 as you have noted and 14500 mm for comp 8. The sum of compartments lengths 4 to 7 would appear to be 20 x 2900 mm although your value of 57383 mm (more accurately 57275 mm) would suggest 19.75 web spaces which still corresponds to a frame space and may suggest a small step in the bulkhead between comps 7 & 8 - see this bulkhead on the Centreline shown on Deck 1 relative to that between cabins. Given that the original arrangement drawing is little more than a sketch I would be surprised if you could get things any more accurate than I have suggested but I would think that 725 mm and 2900 mm multiples should be your goal. That gives:
Comps 3 & 4 = 11600 mm
Comp 5 = 10150 mm
Comp 6 = 18850 mm
Comp 7 = 16675 mm
Comp 8 = 13050 mm but this might be as much as 15225 mm depending in the accuracy of the sketch and the alignment of the forward bulkhead!

You may care to note the fact that the after stairwell drops to deck 0 and that in the inclined state the after corner of deck 1 is totally immersed. Was it access in this area that led to progressive flooding before the final catastrophic capsize that was probably occasioned by further damage on the starboard side from grounding on the rock shelf?

I hope this helps!

 

[smartbight]

I hope this helps!

It does indeed. Thanks. I gave your notes to the drafter so he can update his drawing. I am preparing another batch of pictures & questions for your review.

 

[Starbuck1]

4 or 5 compartments flooded?

Based on these (great!) more carefully scaled dimensions and drawings, showing four compartments penetrated, when the engineers reported 5 compartments flooded or flooding,which five were they? Forward or aft of the 4?

If the fifth compartment was forward, any proposed route other than an open WT door?

When the boulder made its entry, did it distort, crack or open up the bulkhead aft of that or dislodge the motors or shafts in some way that would allow the next compartment (the area around the shafts) to flood?

Where & when is the starboard side damage from the final grounding proposed to have happened? At grounding when it would accelerate the flooding or when it rolled rapidly onto its side which would be after the critical point? If in the "white" part of the hull it may have been too late to be significant, she'd already rolled.

The proposed "Damaged" waterlines in your drawings make it look like the water was barely able to enter from the mooring deck area. Is this correct? The first "lit up and grounded, boats in davits" photo makes the stern look deeper, with the water at the porthole level of deck 1 rather than just at the deck level. This would possibly put water in the passageways and cabins almost forward to amidships on Deck 1 "Olanda".

Would there have been open or openable stairs going down from the Mooring Deck into the crew quarters? Deck plans show no details. Would the doors have been watertight going forward from the mooring deck to the passenger quarters?

These latter three questions are the essence of the "unbalanced flooding through the stern/mooring deck" theory.

 

[Starbuck1]

One other question. In the ship's 4-5 compartment flooded state at the 180º turn, would the wind pressure of the 12 knot wind on the roughly 100,000 square feet of side area be sufficient to cause the ship to heel enough to start the bias toward the starboard side flooding?

 

[IEWinkle]

Based on these (great!) more carefully scaled dimensions and drawings, showing four compartments penetrated, when the engineers reported 5 compartments flooded or flooding,which five were they? Forward or aft of the 4?

If the fifth compartment was forward, any proposed route other than an open WT door?

When the boulder made its entry, did it distort, crack or open up the bulkhead aft of that or dislodge the motors or shafts in some way that would allow the next compartment (the area around the shafts) to flood?

Where & when is the starboard side damage from the final grounding proposed to have happened? At grounding when it would accelerate the flooding or when it rolled rapidly onto its side which would be after the critical point? If in the "white" part of the hull it may have been too late to be significant, she'd already rolled.

The proposed "Damaged" waterlines in your drawings make it look like the water was barely able to enter from the mooring deck area. Is this correct? The first "lit up and grounded, boats in davits" photo makes the stern look deeper, with the water at the porthole level of deck 1 rather than just at the deck level. This would possibly put water in the passageways and cabins almost forward to amidships on Deck 1 "Olanda".

Would there have been open or openable stairs going down from the Mooring Deck into the crew quarters? Deck plans show no details. Would the doors have been watertight going forward from the mooring deck to the passenger quarters?

These latter three questions are the essence of the "unbalanced flooding through the stern/mooring deck" theory.

The damaged waterlines are incorrectly shown and are being corrected. The extreme draft aft on the centreline should give a freeboard of about 2 m over the 14.18 m depth, but with the list to starboard this would place the after starboard corner of Deck 1 about 2.2 m underwater, matching the photo. However, there should be no access to the passenger space from this waterline. To reach this condition, the water must have flooded up into the lower decks (A & 0) to starboard in preference to port from the machinery spaces. Once firmly grounded other openings could have contributed to the capsize, but the most salient point is why was there progressive flooding of the decks A & 0 to starboard before grounding? This destroyed what was otherwise a stable survival condition.

 

[smartbight]

The damaged waterlines are incorrectly shown and are being corrected.

Attached Profile Drawing, Rev. 2 With partial corrections & added details.

Do not hesitate to suggest additional corrections.

Questions:

We are thinking that the motor room may be in compartment 5 instead of 4 as it gets fairly narrow in the stern around comp. 4. ?

Is the center line open space, between rows of cabins, on most decks, a 'utility' corridor for all the 'hotel' piping, AC ducts, electric cables, etc. ?

 

[Starbuck1]

Hi Smartbight,

I'd agree with #5 rather than #4. If you look at the Costa Victoria drawing of a smaller but very similar ship with similar layout, it shows the motors in the 5th compartment going forward, just behind the generators, and some equipment I can't identify in #4 aft of that.

FYI I like the rising angle of the damage you show, suggesting that as the ship took the blow, skidding in the turn, it naturally heeled over further until shearing the rock off the the underwater point, and kicking the stern to starboard and breaking free (minus 8 knots of speed). The rocking therefrom would match the video of the moment.

Going back to my prior question, your drawing clearly shows the four compartments that were torn open and flooded, but was the fifth compartment the engineers stated as flooded forward or aft of these? Any info?

By the way, a much clearer job on the waterline and description of it aft. Thanks!

Another request, would you please do a cross section at the stern and engine rooms showing the waterline's progression as the ship sank deeper and listed further? 13.2º, 20º, 30º? Do we know or have a good guess as to when, (2315-0100?) and at what list angle (20-30º?) it was at before it lost all stability and rolled onto its side?

I'm particularly interested in where the passageways going forward would have been relative to the waterline (I'm assuming that a door was open between the mooring deck and the passenger's or crew's quarters). There had to be an access somewhere down or forward for the crew to access the mooring deck for both lines and people, and to escape.

To pursue the progressive flooding process a little further, a cross section with list angles would also show at what point or how much angle was needed for the WT bulkheads to be overtopped (assuming they were functionally open at the top), or trap buoyancy per the idea of a "lifebelt" forming on the C & 0 decks (3 & 4 SOLAS decks).

Thanks!

 

[Starbuck1]

Re the central corridor between cabin rows, yes, in hotel operations there is often an "alley" where the housekeeping functions and all that ugly wiring, ductwork and piping can be hidden yet accessible for maintenance. It follows the "disney" fantasy model of keeping the real working stuff hidden from the customers as much as possible.

 

[hjmontes]

Dear all, I enter today, as first tme in your for, and watching the general arrangement plan of the file "CCONCORDIA profile+decks.pdf", I can see that the hull damages in are to starboard side and therefore it seems correct that the damaged WL of starboard be higher than Damaged WL larboard, that would implicate a list to the starboard side.
Everything correct under those suppositions, but all pictures, movies etc. shown that de damage are in the port side. Therfore the damage WL's and list sould be totally reverse (more draft at port side and less to starboard side and a list to this side {Starboard}) at the begining of the damage, just in the moment when "Costa Concordia" touch with a rock near the "Isole Le Scole", placed southward the Habour of Giglio in the Island of same name.
What is the reason why finally the boat runs aground lolled toward the starboard side?

 

[hjmontes]

About the Costa Concordia

Dear all, I enter today, as first time in your forum, and watching the general arrangement plan of the file "CCONCORDIA profile+decks.pdf", I can see that the hull damages in are to starboard side and therefore it seems correct that the damaged WL of starboard be higher than Damaged WL larboard, that would implicate a list to the starboard side.
Everything correct under those suppositions, but all pictures, movies etc. shown that de damage are in the port side. Therfore the damage WL's and list sould be totally reverse (more draft at port side and less to starboard side and a list to this side {Starboard}) at the begining of the damage, just in the moment when "Costa Concordia" touch with a rock near the "Isole Le Scole", placed southward the Habour of Giglio in the Island of same name.
What is the reason why finally the boat runs aground lolled toward the starboard side?

 

[Starbuck1]

Good question

HJMontes,

That is what we are all trying to figure out. The original 7º port list evened out as the engine rooms flooded fully, then changed to a starboard list at the time the ship lost way, was blown 180º and started drifting back to Giglio.

Suspects examined so far include:
1. Unknown starboard side damage at the time of first sideswiping the island,
(no evidence or testimony to support)
2. Wind on the large high sides during weakened stability, (probably not enough force given 12 knot wind unless stability was much weaker than we think)
3. Open watertight doors on the starboard side near the flooded engine rooms (no confirming information but a likely suspect)
4. Open watertight doors or passages at the sinking stern (which wouldn't have started the list, but may have made it much worse or fatal to the ship.)
Incorrect transfer of ballast/fuel to correct for a port list.
5. Later starboard side damage when the ship grounded near Porto Giglio (this wouldn't have started the list but could have made it much worse)
6. A shift in the pivot point from the center of remaining buoyancy to the contact points of grounding when it grounded near Porto Giglio. If these points were near the centerline could have made a bad situation much worse. (not much discussion yet, but would not have started the starboard list.)
7. Various combinations of the above, in parallel or series. It gets complicated fast.

We are frustrated by a lack of data or actual plans of the lower part of the hull, having only poor tourist drawings of upper decks and cross sections of other similar ships. We have had some very good modelers using the lines and some good estimates put together a working design/model of the ship and they are refining it.

Look at prior posts by IEWinkle and Brightbight in particular for drawings, modeling and analysis.

 

[smartbight]

Hi Smartbight,

I'd agree with #5 rather than #4. If you look at the Costa Victoria drawing of a smaller but very similar ship with similar layout, it shows the motors in the 5th compartment going forward, just behind the generators, and some equipment I can't identify in #4 aft of that.

...........

Going back to my prior question, your drawing clearly shows the four compartments that were torn open and flooded, but was the fifth compartment the engineers stated as flooded forward or aft of these? Any info?

........

We took another look at the side damage picture; there is no doubt #8 was damaged, for a total of 5 comp. as reported by the engineer.

We moved the motors fwd. Do you have the sketch of the Victoria or where to find it ?

I gave your request for cross sections to the drafter for his consideration.

Thanks for your review. With help from the forum we will get it right.