# Costa Concordia, 80 deg list, really scary !!

Discussion in 'Stability' started by smartbight, Jan 15, 2012.

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### IEWinkleRetired Naval Architect

Oops! Apologies and please note my correction to earlier post where I got my starboard mixed up with my port. Any heel due to the lateral side force would of course be to port not starboard!

If you want to see the rest of my analysis of the event it is posted as No 58 on the following discussion thread:
http://www.boatdesign.net/forums/boat-design/simulating-costa-concordia-41365-4.html#post529743

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### nettersheimConsultant

If we assume heel only = 10° , simple geometry shows that it gives 0,70-0,8 m distance from vertical to ship's sides at 4,00 m draught , which may explain present damage configuration => double bottom apparently not hit and and main damage on the sides.

10° of heel is i.m.o a minimum when hard a starbord at 16 knots (I have experience of more list on large ro-pax vessels in similar conditions). When VDR will "speak", the rate of turn data (this kind of sensor is compulsory on such vessel) will be known...normally.

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### nettersheimConsultant

You raise an interesting question.
Devil is in the details, as usual.
With probabilistic rules it's not a matter of devil but only opacity...

Reg.8 of SOLAS 2009 is a pure deterministic rule among a full brand of probabilistic requirements. The thing may appear curious. In fact when developping the SOLAS 2009 rules at IMO some countries have been reluctant to release pure probabilistic rules and they have lobbied in order to maintain which looks like a "life-line" made of deterministic principle. Probabilistic rules appeared like a "black hole" to these IMO Members !

Some current vessel stability files indicate that in some conditions the Reg. 8 is the most demanding rule.The problem, as you mentioned it, is this rule is a "one compartment + something (?) standard"...

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### IEWinkleRetired Naval Architect

I cannot understand why you are fixated on a rock being picked up 'from the sea bed' when it is clear that the small rocky islet (the last of several projecting from a ridge on the island) that the ship side-swiped falls away almost vertically to the sea bed at depths of over 60m. It is also not surprising that a sheared off bilge keel would drop down below the point of impact to be found lodged in the rocks below. With a heel of 5 degrees to port due to the turn an impact point near the bilge keel would be some 9.2 m below the surface. To scoop the same rock with centroid 4.2 m above the bilge keel only requires a total heel of 20 degrees. Other variants are possible with significantly less total heel depending on the part of the 'rock' which ripped off the initial length of bilge keel.

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### smartbightNaval Architect

This Is What Happen When You Run Into A >side< Can Opener. No damage on bottom !

Prof. Winkle judiciously pointed out the M/V SHARDEN in his post #956 on the "last voyage of the Costa Concordia" thread. A case very similar to the CC (as shown on pictures) but with a totally different outcome. Thanks to a new ferry design evolved from the Estonia ferry & others' tragic ends, and built by Fincantieri, no less.

[ We just learned that this Sharden 'accident' is just part of full scale tests, performed by the Italian CG to prove to skeptics that side damages are caused by using the 'can opener' on the side. No bottom damage unless you use the can opener on the bottom !. No chunks of pier in the 'rip' either since it is reinforced with 'Sheffield' steel rebars, no doubt ! ]

Just two tugs required to move the Sharden to the 'infirmary' A small diesel oil shine on the water to mop up. And a hot plate of Espaguety a la bolognesa +1 glass of chianti per passengers (E 50.0 vs E 11.000 compensation). No coroner involved either.

Mr Costa would trade anytime, and wonder, in his nightmares, why he didn't get a ship like that ?
We do expect to see this type of judiciously located 'wing tanks' (with equalizing ducts, if needed, as per attached study) being adopted and even mandated by the Owners themselves .... post Concordia.

The final 'cost' to Costa is going to be so huge that, looking back, a little extra steel below (+overtime hours from NAs with their thinking caps on) would have been a drop in the bucket. In addition; They are now talking about pollution of a 'pristine' coast if that bunker C get out. Those Cruise Ships are mostly built to take the tourists to those 'pristine' and interesting places, as close to shore as possible. If you have spend time on ships you know why: It is boring out there, at sea, unless you can spot ... a couple of whales copulating close by ... or share your cabin with a Moldavian Beauty !

Most 'workboats' designers have learned all this a long time ago working on designs of all sizes and shapes (carrying ... not even paying passengers ... just lowly PACs).
Nowaday, if we designed a 'workboat' without 'wing tanks' in way of engine rooms, the Owners would kick our 'butts' so hard we might land on the North Pole ... if we are lucky!, but most probably just in the unemployment line, for sure !

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### IEWinkleRetired Naval Architect

Horses for courses I'm afraid! Put the Sharden in a side collision with a bulbous bow and she would probably capsize while the Costa Concordia would survive with no problems!

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### FlariNew Member

Hi all!

Since the accident of the CC I occupy myself with the theme and have made ​​many considerations and calculations in German forums.
Unfortunately, these are not so very professionally.

A few days ago announced the conspiracy theorists "Heiwa" in to this on a forum, in this case http://forum-schiff.de/phpBB3/viewtopic.php?f=2&t=4193 and asked about the most primitive navigational statements.
I tried to explain ..
And I was the one who brought the 20 ° angle of heel into the game.
Just as an example.
He has not understood it.

I do not like conspiracy theorists, and looked so different to his field of activity.
So I ended up here.

I have read many interesting articles and think that I can bring in myself.

Life is for learning.

greeting Flari

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### FlariNew Member

Has anyone here the original AIS data?
You see them may very much.
But you may has to handle with them.

There is no absolutely accurate data.
All data must be interpolated to receive the desired result.
And it is bad if someone else has previously interpolated.
Still, there is often much to explain.

I have received a lot of data from QPS http://www.qps.nl/display/qastor/2012/01/17/20120117_stranding, unfortunately, not raw data.

An interpolated dia from the chart, is this:

I think it says a lot.
Also to the heel.
The AIS-antenna with the GPS-receiver is located about 50m to 60m at height ..

Blue is the ROT of heading (per minute), red is ROT of COS (p/m) and green the difference between the real data.
If it's a heel to one side to the other gives that falsified the true course of rate change to COS..

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### HeiwaNaval architect

It seems we agree that the bilge (keel) may have contacted the seabed because it becomes the deepest part of the vessel when heeled. But only the bilge keel appears to have been ripped off - the flat bottom of the ship and the double bottom - the grounding protection - is intact.
Instead we have this strange structural damage above the bilge in the vertical side up to 1 m below waterline, side pushed in, 100 tons boulder resting on top of the double bottom ... and I just wonder how it came about.
Strange 'experts' say it is due to running aground ... but the ship didn't run aground; the ship contacted something - an outcrop of a rock below water? - and it would be intersting to know what it could have looked like before it was sheared off - by what? The bilge keel? - and became a 100 tons 6 m tall boulder. As the seabed is very steep I would assume the ship should just push the boulder down the seabed - it rolls away down on the seafloor! How could it be flipped up into the ship? :?:
Aha - the Master did it! The magic Master! Or his mysterious girl friend.

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### smartbightNaval Architect

We hear you!
Here we try to stick to good old Newtonian mechanics, for the most part. Although I noticed some of the members were talking about lighting up their Hookahs, on the other thread, "last voyage of the CC" ... then all bets are off !

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### Pascal WarinJunior Member

Not to somebody not speaking German.

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### hoytedowWood Butcher

Kurs = course
änderung = change
diagramm is pretty self-explanatory
zwischen = between
Havarie = accident
Lage = location
Wahrscheinliche = probable
Überschwinger = overshoot
Backbord = port
Steuerbord is self-explanatory

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### IEWinkleRetired Naval Architect

Try looking 47 secs into the 3D reconstruction of the incident in http://www.qps.nl/display/qastor/2012/01/17/20120117_stranding
Pay particular attention to the sea bed profiles in relation to the port & starboard sides.

This gives a very clear idea of how the rock can have been scooped into the hull by being enveloped by about 3-4 m of structure as the result of the ship side caving in as the ship slammed into the rocky promentary.

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### nettersheimConsultant

Again an interesting point.

SOLAS 2009 is highly demanding in terms of progressive flooding analysis. It is a big job now for designers/ship builders -and class during approval process.

The problem with SOLAS 2009 is that there is no more limit for vessel sinking. Like the "good old B/5 limit" as you said, the also "good old margin line" has disappeared in the rules. And this is of some concern for several persons (researchers, NA, legislators and operators).

For ship captains/officers the damage controls plans are definitely non legible in certain ship's files produced by shipyards and ... approved ! For example what is the practical meaning of survivability factor "s" switching to zero (s=0) in case of immersion of particular area if you don't have parallel information such as V-lines or similar ? ect...ect...

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### HeiwaNaval architect

As you can see from below photo I have taken of the alleged location of the first incident - the contact

there are two rocks outside the Isole del Scole which in turn is outside Isola del Giglio. You also find the photo at http://heiwaco.tripod.com/news8.htm
Let's say that the port bilge and flat bottom forward of L/2 of CC contacted the sea floor outside the outermost rock and was ripped open. If CC was turning or on straight course doesn't matter. It was a first CC bottom fwd contact. Has anybody inspected the port fwd flat bottom?
Thus CC would lose buoyancy in port fwd double bottom and heel to port (and trim on the bow).
Due to the heel to port the port vertical side aft could then make a second port side shell below waterline contact with the outermost rock higher up and shear off the famous 100 tons piece of rock loaded on the top of the double bottom.
One problem with this hypothesis is that the stabilizer fin located between the two contacts is not damaged - but maybe it was extended after the two contacts - port bottom fwd, port side aft?
Anyway, a shipowner that propose to their Masters doing show boating very close to shore is not diligent.

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