need help in Damage and Probailistic stability

[sudhir0201]

Dear friend
i m a new member of Boat design. i m working on Damage and Probabilistic stability of aircraft carrier. but i m facing problem doing probabilistic stability. i m using TRIBON M3 software for calculation, but problem is that it does not have any criteria for aircraft carrier. it only have criteria for merchant ship. please help me , how i approach for this, i will be very thankful for any kind of help.

[ontwerp]

That's interesting, I didn't think that military vessels need to have probabilistic damage stability calculated.
But if you are looking for criteria - I think the ministry of defence from the country who is ordering the aircraft carrier should have a set of relevant criteria that they want you to use.
Good Luck!

[jehardiman]

As ontwerp says, if you really need that info you should be getting it from the Indian MoD. There have been some open literature papers on probabilistic damage to warships. Check the RINA or SNAME papers lists.

[sudhir0201]

Thanks for the reply. no dear, military vessels are also using probabilistic stability, to know the damage condition after hit by an torpedo or missiles.
as you mention , ministry of defence of a country gives a data like what type of weapons they are using, what are IR signature, which type of radar they are using.etc, but as all this is new for me. i want to know that how i start, i don't know nothing about probabilistic stability. so can you help me to understand all this. can i get some criteria from other country which could helpful for me.

[ontwerp]

If you want to know some more about probabilistic damage stability theory, you could take a look at this thread which was posted a while ago, but I think the information is more or less up to date.

Probabilistic damage stability

[sudhir0201]

thanks ontwerp,
for this valuable information. but with the help of tribon m3, how i solve probabilistic stability for warship. can u help me in this. or i have to use some other software??

[ontwerp]

I've never used Tribon, so I don't know if or how it calculated damage stability.

Both Napa and Delftship can calculate probabilistic damage stability well. Napa is used by most classification societies world wide and is very accurate, but is hard to learn.

Delftship also calculates damstab well and is much easier to learn but it not as well known as Napa and you might need to prove the calculations are correct if you submit them for approval to a classification society outside europe.

Other programs calculate probabilistic damstab, but we use Napa and in my opinion it is the best software for damstab and easiest to use for optimizing your design (once you've learned how to use it) and the results are easily accepted by class. since they probably are using the same software.

[sudhir0201]

thanks ontwerp
ya i know, NAPA is a good software. and i also want to learn it. can u provide me setup of this software, or send me details or link from where i can download this software. i m very keen to learn this software.

[sudhir0201]

is anybody help me to get NAPA software,

[ontwerp]

Hi Sudhir,

As far as I know, the only way to get Napa is to buy it. The website is www.napa.fi

...and it ain't cheap

Maybe they will give you a trial version if you ask nicely?

Good luck!

[sudhir0201]

hi ontwerp
means it is not available on internet?

[Jeff]

On the internet go to www.napa.fi
I don't believe there is any public demo/trail version link - contact them.

[nettersheim]

Napa is very very expensive.

The Finnish company has developped the sofware carefully since now a long time (I mean the probabilistic damage stability part) upgrading it from old IMO resolution A265 (1974) up to Solas 2009 and they know that they are quite alone on the market...

As already explained by other Colleagues in these posts, the software is used by large shipyards and class societies all over the world, and this is becoming a problem for a unique product is used by designers, builders and approval bodies (research institutions are using it too !).

[wimal]

Probabilistic damage stability assessment methods are given in SOLAS booklet publish by IMO. The method vary depend on the passenger vessel or cargo vessel. For Cargo vessels the method has been introduced very recently. I have a software developed for damage stability assessment during my Ph.D. I have already used it for more than 25 practical cases.

[nettersheim]

Hello Wimal, and All,

From an historic point of view, we can say:
- 1974 OMI Resolution A 265 for passenger ships as an alternative to Solas 1960 chapter II-1
- 1992 Solas 1992 for cargo ships (based on A265...) [=> probabilistic damage stability for cargo ships is not a recent matter]
- 2009 , present Solas for cargo ships and passenger ships (passenger ships until Solas 2009 was designed under old deterministic principles except if A265 was used)

Wimal, which kind of sofware exactly have you developped for your Ph.D ? I am involved in probabilistic damage stability for pedagogic, lecturing aspects and obviously your message has raised my curiosity ?