Costa Concordia, 80 deg list, really scary !!

Class rule (i.e. SOLAS) talk about Probabilistic damage stability where probability to take certain damage is multiplied by probability to sink (or make the evacuation of personnel "impossible") if that damage did occur; than possible cases and their combinations result in certain "index", higher for passenger ships than for cargo ships. In fact the indexes for cargo and passenger ships are calculated to different procedures.
The philosophy under it is you cannot build a ship that is unsinkable.
You only can build a ship that is ""unsinkable" enough".

 

The impression I get is that the ability of these mega-liners (water-borne high rise accomodation for extra capacity) to withstand holing without becoming dangerously unstable is compromised by the sheer size of them allowing a relatively higher centre of gravity than if they were built to a much smaller scale, and the influence of waves needing more to be taken into account.

 

My professional opinion is that water got in the people tank.

Of course thay are, but as has been pointed out on numerious occasions, the only way to make ships unsinkable is to set them in concrete pierside. But that is not what ships are for. It is impossible to make a ship operator proof, becuase they are cunning, persistant, and have power tools.

 

Maybe the captain drank too much

 

There is another thread http://www.boatdesign.net/forums/open-discussion/last-voyage-costa-concordia-cruise-ship-41313.html talking about the Costa Concordia grounding in general.

 

I love a comment by industry expert on the BBC
"these ships are made for revenue not safety"

That the 2nd one to fall over the last one only had a single tank punctured and the captain got everyone off to be safe then it just fell over..

 

Be some very cheap cruise deals going soon.

 

How stable are cruise ships like the Costa Concordia?

* 16:30 16 January 2012 by Paul Marks

http://www.newscientist.com/article...re-cruise-ships-like-the-costa-concordia.html

One of Europe's largest cruise ships, the Costa Concordia, carrying 4200 passengers and crew, suffered a fatal and spectacular accident on Saturday. The vessel was holed on rocks off the Italian island of Giglio – and then quickly keeled over, preventing lifeboats on its port side from being lowered and trapping some passengers and crew in the bowels of the ship. At 12:00 GMT today, six people had been confirmed dead and a further 15 were missing. So how stable and safe are these vertiginous floating multistorey hotels?

Why was this massive ship so close to shallow rock outcrops?
Mark Staunton-Lambert, technical director of the London-based Royal Institution of Naval Architects, says this is the main question investigators will want answering. GPS and sonar instruments should have warned of the danger, he says.

...

The ship keeled over pretty quickly. It's 13 storeys high yet only 8.2 metres of the vessel sit below the waterline. How can that be stable?
The International Maritime Organization (IMO) specifies the stability that ships must have – and if a vessel complies with those rules it should be fine, says Staunton-Lambert. All the heavy stuff – the engines, water ballast tanks and fuel oil – are kept low in the hull, and the tall accommodation blocks above are largely empty space peppered with much lighter contents: people and furniture. "These cruise ships may seem high," says Staunton-Lambert. "But the trick is to ensure that the weight distribution is correct, focusing on where the centre of gravity is."

How is the degree of stability of such a ship decided?
The IMO regulations specify how quickly the vessel must return to upright when it has been upset by freak weather, a grounding or a collision – and is has to do this even if damaged.

...

Read more http://www.newscientist.com/article...re-cruise-ships-like-the-costa-concordia.html
----------
There were 500,000 gallons of fuel on board, in 17 separate tanks, Foschi said.
------------

 

Posted on January 16, 2012 by Rick Spilman

One of the more alarming aspects of the sinking of the Costa Concordia was the dramatic roll that the ship took after the grounding. She is now sitting with a list of roughly 80 degrees with almost half of the ship flooded. Passenger ships have been designed to avoid listing when damaged since at least the Lusitania in 1915, when longitudinal bulkheads which allowed flooding only on one side of the ship, accelerated the capsize and sinking. The Costa Concordia however is in a different situation. She is resting on a rock ledge. Once the ship was no longer floating but supported on rocks, she lost stability and rolled on the uneven bottom.

There is now concern that in deteriorating weather, the ship might slip off the ledge into deeper water. Rescue efforts on the ship were suspended indefinitely today when divers heard noises suggesting movement. Thus far, the recorded movements of the ship have been small but if the ship does sink in deeper water the environmental impact from the leaking of the ship’s fuel tanks could be significant. The Dutch salvage company, Smit Tak, has been contracted to pump fuel from the ship and begin salvage operations.

...

http://open.salon.com/blog/rick_spi...ip_roll_and_is_she_slipping_into_deeper_water

 

Are you Mr. Spilman?, because he did not post in this thread. Where did you get copy that from?

Obviously, you understand little about ship stability, damaged or otherwise, because this is not an unexpected condition. Draft at unstability is a common calculation for all NA's. ANY vessel will capsize on point grounding! If all you are looking for is panic quotes, go copy the Italian newspapers.

 

" If all you are looking for is panic quotes "

No need to! CNN is doing a good job at that. Today, they just announced 5 more bodies recovered. 24 more to go according to the Carabinieri ..... for next week ?

"Obviously, you understand little about ship stability, damaged or otherwise, because this is not an unexpected condition."

These are the same words Tomas Andrews told David Wilson when they shook hands on the deck of the mighty T. David told him he was getting off (David survived).

{ A cruise ship design technical expert today dismissed suggestions that huge modern liners lacked stability.
The sight of the 114,000-tonne Costa Concordia lying on its side off the coast of Italy has raised questions about the safety of such mega-liners.
But such gigantic vessels are in fact safer than ever, according to Robert Ashdown, the European Cruise Council's technical, environment and operations director.
He said today: ''It's just not right to say that the design of the hull of these big ships is unstable. These ships are more stable than they have ever been.
''They can stand up to anything the weather can throw at them. They are designed to strict international standards.''}

Mouthpieces getting their paycheck from the Billion $$$$ cruise/passenger industry like Robert Ashdown, Bruce Ismay and others... will tell you that "such gigantic vessels are in fact safer than ever." Once all the bodies are recovered they will tell you 'Very sorry for your loss, we feel your grief. After all the international standard we used were not strict enough.'

On this thread, we are trying to gather all 'available info' relevant to the stability of 'legitimate' passenger ships and also what I would call 'Wedding Cake' designs cruise ships like the CC.
By the tone of your post, it sounds like you have valuable knowledge and experience on the subject that you may want to share on this forum ???

 

They ARE safer than ever, even including fire, which is the most dangerous thing afloat.

Modern cruise liners are more stable than ocean liners of 50 years ago. Compare this loss to the SS Andrea Doria which did capsize and sink after much less damage (and in which some of the crew also took to the boats first), and will have similiar loss statistics. So I bet casualties caused by the design and stability of this vessel are much less than those caused by the panic of individuals (Never leave the ship until you have to step up into the lifeboat) and confined to those lost immedialtely due to catasrophic flooding of the breached compartments.

There is nothing technically unexpected in this loss given the amount of damage. This is very different from the loss of the M/V Rocknes in which the greater majority of the crew died from a very small hole that caused loss of stability. The capsize is a function of the grounding combined with the loss of waterplane area (basicly the aft 1/3 of the ship) and there is a whole section in PNA devoted to grounded stability and these issues. FWIW, the 50m damage length is approximately equal to 2-3 adjecent contact torpedo/mine hits, so compare it to the HMAS Britannic, RMS Lusitania, and M/V Wilhelm Gustloff. Merchant ships, no mater what thier size, are not designed to continue to float after this type of damage and only have to remain intact long enough to evacuate the passengers and crew.

Like the loss of the S/V Concordia, this was a wholly preventable loss. And like the the recent losses of S/V Concordia and the M/V Explorer, the present stability and subdivision requirements are shown to be adaquate in that all 3 vessels were abandoned successfully with no or minimal loss. If you want to know more, then I would recommend you spend some time reading the SOLAS guidelines and your client state requirements on the history and reasoning of probability based damage requirements.

I don't understand why this is such a hot button. It is like saying that an airplane should survive a mach 0.8 impact just in case the pilot flies it into a mountian. That's not going to happen. Naval Architects such as myself understand that the lives of people depend on our decisions, but we also realize that there is no perfect safety in anything...period. Given the circumstances, the ship performed as well as could be expected, and there might even be some small take-aways to make ships even safer than they are. Would that the same could be said for the command team.

 

was anyone on this forum involved in the design or build of the costa ships

 

I don't think we'll be seeing the word "Concordia" in too many boat names for a few years to come...

-Tom

 

Oddly, the Concorde also suffered from a crash.