Tanker Barge 15.8x6x3

Discussion in 'Stability' started by naserrishehri, Jul 5, 2015.

  1. naserrishehri
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    naserrishehri Senior Member

    DEAR FRIENDS
    there is a tanker barge(15.8X6X3m) with a single tank (9.8X6X2.9m) in the middle and carry fresh water.
    i want to calculate the minimum free board for that barge.
    which criteria shall i use for stability analysis?
     
  2. Jamie Kennedy
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    Jamie Kennedy Senior Member

    Is your tank half empty or half full ? ;-)
     
  3. TANSL
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    TANSL Senior Member

    The freeboard of any boat is governed by the International Convention on Load Lines, 1966 and subsequent amendments. In principle it has nothing to do with the stability but with reserve of buoyancy.
    If you have to calculate stability after damage, the boat, in the worst case of damage, can not submerge the margin line. This can give you an idea of the minimum freeboard must, from this point of view.
    Stability criterion ? : as a tanquer or as a barge, depending on how are you considering your boat.
     
  4. naserrishehri
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    naserrishehri Senior Member

    there is no criteria in is code 2008 for vessels under 15m.I can not consider it as pontoon because b/h ratio should be more than 3 and it should be deck cargo.
     
  5. TANSL
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    TANSL Senior Member

    Even for calculating scantlings, you must know if it's a tanquer or barge. A barge not self-propelled. Perhaps you should consider a normal freighter, loaded on deck, and a large water tank.
    If in doubt about the criteria, it is best to consult with the local maritime authority.
     
  6. Jamie Kennedy
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    Jamie Kennedy Senior Member

    Would it qualify as a fishing vessel or something general if that length, particularly where it is fresh water and not something that may requiring regulation? Is the fresh water to be sold, if that matters?

    p.s. If a tank is half empty, does it require more margin of safety than a tank half full? ;-)
     
  7. TANSL
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    TANSL Senior Member

    If we are talking about water for drinking water for the crew or to be sold, it is always much safer ship if it is half full. It is logical, right?
     
  8. Jamie Kennedy
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    Jamie Kennedy Senior Member

    Those with their tanks half empty might disagree.
    To them nothing is safe enough. Not logical, but there it is. ;-)
     
  9. TANSL
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    TANSL Senior Member

    They might desagree but they are not rigth. It is not a matter of logic, but of safety. Nor is it a subjective matter.
    It's easy, think a bit about it.
    Since this is not what naserrishehri wondering, I will not continue along this path.
     
  10. Jamie Kennedy
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    Jamie Kennedy Senior Member

    I think I was being too subtle. I was trying to make a joke about optimists thinking their glass is half full while pessimists see their glass as half empty. There is no doubt a similar saying in Spanish but it didn't translate well when talking about tanks and ship stability. My apologies. :)

    https://www.youtube.com/watch?v=u7Ty3fggeBA
     
  11. TANSL
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    TANSL Senior Member

    From the first moment I thought it was a joke, given how irrelevant was the question. I also thought that naserrishehri, who has an important question that he wants to solve, the joke would seem very unfunny.
    And, yes, in Spanish also we say something very similar.
    Cheers
     
  12. Jamie Kennedy
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    Jamie Kennedy Senior Member

    Thanks TANSL. Cheers.
     
  13. naserrishehri
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    naserrishehri Senior Member

    DEAR TANSL
    i apologize because i did not clarify the problem well.
    many years ago a vessel was manufactured as the attachment to supply fresh water for other ships in the port.
    i want to calculate a minimum free board for it , so i should consider a criteria for stability calculations.i 'm looking for that criteria.
     

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  14. TANSL
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    TANSL Senior Member

    In my opinion you have to calculate in accordance with Resolution A.749 (18) of the IMO and select one of the criteria that you will find there.
    There is doubt whether your ship can be considered a cargo ship, which can carry cargo on deck and in tanks, or a barge, as the pontoons are not self-propelled. I do not know how to consider it, so I said you should consult with the administration of your country.
    But beyond that, the Load Line Regulations indicates how to calculate the minimum freeboard for any vessel.
    If the stability conditions force you to a higher freeboard, you must take the greatest of freeboard.
    Moreover, I fear the effect of free surfaces of the tank is so big, you have to divide it into several tanks by longitudinal bulkheads and any cross bulkhead.
     

  15. NavalSArtichoke
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    NavalSArtichoke Senior Member

    "Any boat" casts too wide a net where the ICLL is concerned. In particular, vessels which are less than 24 m in length are not required to carry a load line, even on an international voyage. There are other categories of vessel which are not required to have a LL, as is explained in the Convention itself.
     
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