Angle of GZmax

Discussion in 'Stability' started by Abhilash Satheesan, Jan 11, 2018.

  1. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    The USCG Part 170.173.b3 says than the angle of max. GZ mut be > 25 degrees.
    In my opinion, and forgive you if I am very insistent, until you get that, it is useless to continue.
     
  2. Abhilash Satheesan
    Joined: Jan 2018
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    Location: Rhode Island

    Abhilash Satheesan Junior Member

    Yes. You're right. But 170.173 point 1 says the vessel should meet either section 'b or c'. In section c2, the GZmax should occur not less than 15deg. I hope im not missing something here
     
  3. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    I did not know that option. If so, better for everyone.
    However, I have been able to verify that there are 3 other stability criteria that are not met.
    I would like to be wrong but humbly I think that hull has problems.
     

    Attached Files:

    Last edited: Jan 11, 2018
  4. Abhilash Satheesan
    Joined: Jan 2018
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    Location: Rhode Island

    Abhilash Satheesan Junior Member

    Thank you for the word file. Yes, the results fail when 2008 IS Code is performed. But, as i understand, section CFR 170.165b tells us 2008 IS Code and section 170.173 are alternatives. Which i think, mean that only one criteria need to be complied. I'm open to other opinions here
     
  5. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    I do not know if I understand you correctly but the boats must comply with several stability criteria, minimum initial GMt, minimum value of the maximum GZ, angle of that value of the GZ and 2 or 3 criteria relative to the area below the GZ curve. In addition there are complementary criteria for passenger ships, such as maximum angle of heel with the passage to a band, list by wind, etc. All of them, not just one, must be fulfilled.
    If I am wrong and I have not understood you well, I beg your pardon.
     

  6. Abhilash Satheesan
    Joined: Jan 2018
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    Location: Rhode Island

    Abhilash Satheesan Junior Member

    I understand your general view here. I have listed below all stability criteria that for my booklet:
    1. CFR 170.170 (Weather Criteria),
    2. CFR 170.173 (Righting Energy Criteria),
    3. CFR 171.050 (Intact stability requirements for propelled vessels), and
    4. CFR 171.080 (damage stability requirements)

    These were the USCG requirements when similar vessel was built 4 years ago. Hope im on right track?
     
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