Intact Stability and damage stability

Discussion in 'Stability' started by mactavish, May 20, 2015.

  1. mactavish
    Joined: Sep 2014
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    mactavish Junior Member

    Hi all,

    I would like to ask a question regarding on damage stability. How does it can be calculated? I know how to do intact stab. Am i just going to add the damage tank there or i have to do something else? Cause i don't like maxsurf doing it all the way. I prefer to do it manually with excel sheet. Can you please give me a quick brief. Or could you please share your spreadsheets?

    Thanks and regards,
    "Mactavish"
     
  2. Ad Hoc
    Joined: Oct 2008
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    Ad Hoc Naval Architect

    If you wish to do this by hand, it is easy to do, but just very time consuming.

    You can use either:

    The Lost Buoyancy Method
    or
    The Added Weight Method.

    If you are unfamiliar with these then you need to consult a typical Naval Architecture text book..or ask your tutor. As to explain how this is calculated is more than a simple one liner.
     
  3. mactavish
    Joined: Sep 2014
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    mactavish Junior Member

    Just to ask. Am i just going to add the damage tank to intact sta?
     
  4. Ad Hoc
    Joined: Oct 2008
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    Ad Hoc Naval Architect

    If you're unsure of such a basic question with regards to stability, i refer you to my previous reply.

     
  5. mactavish
    Joined: Sep 2014
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    mactavish Junior Member

    Actually i have asked my professor he said just add the damage tank in intact and that's it he said... Because in my point of view if i add the damage tank as weight of course my stability will change and it will of course affect my GZ. And i think this is the add weight method. Now with regards to lost bouyancy it is like you assume that the damage part is part of the sea already. Of course this will result to lost of bouyancy..etc and this is i'm not familiar with.... but still i have the concept in my mind....
     

  6. Don92
    Joined: Feb 2015
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    Don92 Principal Naval Architect

    I would advise you conduct the damage stability assessment using Maxsurf as it would save you a lot of time using this approach. It is however important that you have an understanding of how this software conducts these calculations so that you can set-up the assessment in a correct manner and interpret the results correctly. Maxsurf uses the lost buoyancy method whereby it is understood that the flooded portion of the vessel no longer provides buoyancy and so it can be thought of as open to the sea and no longer a part of the vessel.
    The nature of the assessment really depends on the type of vessel and this will effect the extent of damage you consider. Generally, you will have to define a number of damage cases and proceed to assess the stability of the vessel in the damaged condition against an applicable set of criteria.
     
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