Stability Criteria for TAD Barge

Discussion in 'Stability' started by d362622563, Jan 12, 2013.

  1. d362622563
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    d362622563 Junior Member

    Dear all, this is my first post and thanks for taking time reading it.

    Is there anyone who is familiar with tender assistant drilling barge? I am now designing one, and I want to know what criteria shall I use for intact and damage stability calculation.

    The barge is to comply with ABS MOU Rules and ABS Steel Barge Rules, after reading these rules I feel like complying MODU Rules is sufficient for stability calculation. But I am considering whether I should include IMO A749 for intact and MARPOL for damage, because I may have seen some ship complying these rules.
     
  2. TANSL
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    TANSL Senior Member

    Of course you have to comply with IMO Resolution A.749 of, or equivalent regulations of the Administration of your country . I do not think you have to do any study of stability after damage.
    MARPOL is a regulation on pollution of the sea. If your boat has no danger to contaminate, in general, do not have to comply with MARPOL
     
  3. JRMacGregor
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    JRMacGregor Junior Member

    This is not a SHIP - it can be considered as a MODU. It therefore does not have to comply with IMO SOLAS. Instead IMO will accept compliance with IMO MODU Code.

    IMO MODU Code contains the stability criteria required for MODU.

    For stability rules the IMO MODU sections on SURFACE UNIT are those you have to follow.

    Check with the flag state that they accept compliance with IMO MODU Code (I am 99% certain that they will).

    As already said - you don't need to comply with MARPOL tanker damaged stability criteria for your TAD MODU - so long as you are not storing oil in bulk onboard.
     
  4. d362622563
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    d362622563 Junior Member

    Dear TANSL, thanks for your reply. I have done the calculation for 749 and MODU, actually this barge can pass both of them. However considering 749 the allowance is so small that it makes me a little nervous. Cause this is basic design, I hope it is not only a "pass".

    Basically I most want to know what criteria is contained in ABS Steel Barge Rules, because I didn't find any useful information about stability calculation.
     
  5. d362622563
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    d362622563 Junior Member

    I have to say that I am very glad to hear this. In MODU I found criteria as follows:

    Intact:
    1. All units are to have positive metacentric height in calm water equilibrium position for all afloat conditions, including temporary positions when raising or lowering.
    2. For surface and self-elevating units the area under the righting moment curve to the second intercept or downflooding angle, whichever is less, should be not less than 40% in excess of the area under the wind heeling moment curve to the same limiting angle.
    3. The righting moment curve should be positive over the entire range of angles from upright to the second intercept.

    Damage:
    The unit should have sufficient reserve stability in a damaged condition to withstand the wind heeling moment based on a wind velocity of 25.8 m/s (50 knots) superimposed from any direction. In this condition the final waterline, after flooding, should be below the lower edge of any downflooding opening

    Would you please tell me if these are all the criteria I am going to follow? Thanks for your reply!
     
  6. JRMacGregor
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    JRMacGregor Junior Member

    This looks OK - although I have not checked every detail.

    I think the criteria for MODU in A749 (section 4.6) - where you probably got this from - are the same as those in the IMO MODU Code - which is as it should be.

    The criteria you quote look like the ones in the IMO MODU Code.
     

  7. d362622563
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    d362622563 Junior Member

    OK, thank you very much!
     
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