Intermediate Stages of Flooding(GHS/Autohydro)

Discussion in 'Stability' started by sarath jose p, Nov 5, 2017.

  1. sarath jose p
    Joined: Jul 2013
    Posts: 1
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    Location: chennai

    sarath jose p New Member

    Can any one please help me with the code of intermediate stages of flooding for passenger craft in GHS/Autohydro.
    To verify the following criteria.
    "SOLAS 2000 hapter II-1,Regulation 8-
    2.4 In intermediate stages of flooding, the maximum righting lever
    shall be at least 0.05 m and the range of positive righting levers
    shall be at least 7 deg."
  2. jehardiman
    Joined: Aug 2004
    Posts: 3,515
    Likes: 901, Points: 113, Legacy Rep: 2040
    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    GHS/AutoHydro swill not help you with this.
    You need to understand the criteria.
    Then you can manipulate GHS/AutoHydro to make the calculation for you.
    Computer programs should be your slaves, NOT your master.
  3. Don92
    Joined: Feb 2015
    Posts: 28
    Likes: 5, Points: 3, Legacy Rep: 10
    Location: Glasgow

    Don92 Principal Naval Architect

    Dear Sarath, perhaps to answer in a less patronizing fashion, the intention behind the intermediate flooding stage criteria is to account for the potential that certain stages within the flooding evolution, prior to equalization, could in fact possess greater vulnerability than the final stage i.e. the equilibrium condition. By implementing such criteria it is hoped that vessel's are design with sufficient stability such to withstand the effects of 'transient' flooding which relates to the initial stages of flooding and which comes as a result of elements within the vessel's internal geometry design that retard the flooding process. This includes such features as cross/down-flooding ducts/flaps and other internal structures such as fire walls which are likely to inhibit instantaneous equalization. When preparing your calculation you should be wary of such design features and define your damage cases according to such design elements. Unfortunately I tend to use Napa and therefore cannot address your problem specifically, but you should define your damage cases in a manner, such that depending on the stage of flooding you apply the correct criteria. I know that within SOLAS 2009 this is a time dependent parameter, as you would imagine, and depending on the equalization time various stringency in residual stability requirements apply. For example, if the equalization time is less than a minute then the flooding process is assumed instantaneous and intermediate stages need not be accounted for. If the equalization time is greater than 60s or if active cross flooding techniques are applied, then the intermediate stage criteria must be applied and your damage cases for a given compartment must be segregated in to various stages according to different design features which inhibit the flooding process. There is also a stipulation that, should the flooding time take longer than 600s, then the same criteria which would apply to the equilibrium condition should also apply to intermediate stages, though cross flooding requiring a time grater than 600s is not allowed for passenger vessels. I hope this helps!
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