examples of (classed) yachts using bladder tanks

Discussion in 'Boat Design' started by expedition, Oct 16, 2009.

  1. apex1

    apex1 Guest

    The "ventilation" I have overlooked! Hence my comment that of course they "have to" collapse. And yes I thought about multiple bags or liners as I named them, what else?
     
  2. baeckmo
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    baeckmo Hydrodynamics

    Neee Apex, not much, you summed it up pretty clearly. My comment was more towards the blue noses of the LR, who were inclined to reject the collapsing bladder, based on a "nonunderstanding" of the working principles. One of the main features of the bladder is the total absence of vented fuel fumes from a fuel storage!
     
  3. wardd
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    wardd Senior Member

    volume could be replaced by water to maintain trim

    ala, old diesel subs
     
  4. apex1

    apex1 Guest

    That was,nt uncommon, but as Thorwald said, it is hard to find that stuff today. And according to his experience it seems some classification bodies do┬┤nt like it anymore.
     
  5. expedition
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    expedition Thorwald Westmaas

    'salto mortale' and venting

    Nada de salto mortale !!

    We are using a bladder tank NOT because we want a non-venting tank but because we need a flexible tank we can put inside another tank through a manhole. This creates a cofferdam equivalent class is looking for.

    Bladder tanks happen to fullfill that need.

    So of course for this particular application where they are not allowed to collapse, we need to add a venting connection (not to the cofferdam of course). It is exactly this connection (and that of the fuel piping) that class wants fixed which in turn requires it's not collapsible.

    I hope it's clear now.

    Have a look at my post at http://www.expeditionyacht.org/safety/jet-fuel-in-bladder-tank - maybe that clarifies it.
     
  6. expedition
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    expedition Thorwald Westmaas

  7. TeddyDiver
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    TeddyDiver Gollywobbler

    So Thorwald to be precise, what you want is a liner in your tank, not a bladder tank.
    That fire-supressant-material seems to be enough to take care of the non-collapse issue as well..
     
  8. expedition
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    expedition Thorwald Westmaas

    Well, all liner applications I have seen do just that: they line anothe surface to seal it and make it leak proof and are usually open on the top. I need a real tank, a tank that collapses. And we need air around the tank to created the cofferdam function.

    So I'd call it a bladder tank. Just because we put a vent on it doesn't make it a liner.

    No manufacturer I have contacted so far told me 'ahh, you're talking about a liner'.

    Anyway, I'm just happy I found a solution that can be approved by class :).
     
  9. apex1

    apex1 Guest

    Which one now, Thorwald?
     
  10. Yellowjacket
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    Yellowjacket Senior Member

  11. apex1

    apex1 Guest

    Yeah, thats the stuff we need! It seems they have no difficulties to pass the class survey.

    Thank you Yellow.
     
  12. baeckmo
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    baeckmo Hydrodynamics

    Guess we have a question of definition here, to me a "bladder tank" is just that, a bladder. By definition collapsible and without venting and perfect to fit into a closed structure. In my book your arrangement is a liner, and as such in need of a vent. My finger was pointing towards one-eyed rules that have no provision for new thinking. I was not stepping on your toe here (at least not intentionally)!!!!
     

  13. TeddyDiver
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    TeddyDiver Gollywobbler

    ATL seems to call that a "fuel cell"
     
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