recycled water bottle floatation?

Discussion in 'Boat Design' started by jeffb957, Dec 29, 2013.

  1. jeffb957
    Joined: Dec 2013
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    jeffb957 Junior Member

    Hello everybody,
    I drink a LOT of bottled water at work. the thought occurred to me that I could recycle those water bottles by putting the caps back on, and filling the areas under the deck sole with them. seems like a cheap alternative to floatation foam. Of course they;d have to be secured in there, either by glue of some sort, or be having the areas they are filling securely closed so they stay put.
    Seems like a good use of something I would otherwise have pitched. Is there any important reason not to do this that I hadn't thought of?
    1 person likes this.
  2. alan white
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    alan white Senior Member

    It is a good idea. The redundancy of seperate containers means a guarantee of reliability of the flotation medium. The cost is quite low too. Box in the bottles and figure each two liter bottle is worth about 4 1/2 lbs. I would consider this method to be perfect for many situations where light weight is important.
  3. NavalSArtichoke
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    NavalSArtichoke Senior Member

    What happens if the bottles get crushed or holed for some reason? Then your flotation is history.
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    Maybe put them all in a net, something light would suffice, that way they will stay together and not disappear out of any holes ! There is quite a bit of this plastic bottle thing being done, it is almost standard practice in some places.
  5. JSL
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    JSL Senior Member

    If you need floatation for compliance reasons (USCG, etc for small boats) then air chambers are not compliant.
    You will be using lot of space which could be used for storage, tanks, and access.
  6. jeffb957
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    jeffb957 Junior Member

    I'm talking about the half liter water bottles. any one single bottle getting holed would be meaningless. There would have to be dozens holed to make any real differance
  7. jeffb957
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    jeffb957 Junior Member

    As far as I know, we don't have any state laws requiring floatation in owner built boats. I'm just thinking about it for an added safety margin, and for areas too inaccessable to be easily used for storage
  8. NeilG
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    NeilG Junior Member

    As a point of comparison, have you seen the Junk Raft project?
    When they first set off sailing from the USA mainland to Hawaii, they had to make a stop as many of their bottle lids were coming undone.
  9. michael pierzga
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    michael pierzga Senior Member

    Dont waste your time with plastic bottles. Use foam billets or pour foam .

    Pour foam deadens sound, stiffens panel sections and is easy to use.
  10. Village_Idiot
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    Village_Idiot Senior Member

    As I mentioned in the last thread dealing with this (several weeks ago), use the bottles, but add the two-part pour-in closed-cell foam once the bottles are in place in the chamber or bilge. The foam provides additional floatation, holds the bottles in place and keeps them from rattling around. The bottles greatly reduce the amount of expensive poured foam needed to fill a chamber.

    Additionally, I'd remove the labels from the bottles (reduces water/mold aborption) and maybe even glue the lids onto the bottles. I suspect that all foam eventually becomes waterlogged over the years, even from atmospheric moisture. Sealed bottles will help mitigate this effect also.

    You might also want to place some conduit (simple PVC pipe) in the chamber/bilge to be filled, so that you can run wiring, etc. through there if needed at a later date.
  11. jeffb957
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    jeffb957 Junior Member

    Hello V.I.
    I searched for, but could not find other threads on this topic. Hopefully I do better at constructing boats than I do constructing search strings. Your suggestions are well thought out. Brilliant ideas. Thank you
  12. philSweet
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    philSweet Senior Member

    You probably don't want to put them under the sole. They need to up higher in the boat and as far outboard as possible, and high in the ends of the boat, so that it keeps the boat upright. An exception to this is in small boats that can be recovered and sailed away from a deepwater capsize. Floatation under the sole midship will basically do nothing but ensure the boat rolls completely upside down and stays that way.

    With that in mind, bottles and foam work well together and cut cost. I've done this in the ends of boats mostly. Glue the caps on with plactic cement after they've been in the fridge. You want positve pressure. If the boat freezes, you may need to use some chemistry to get enough positive pressure after sealing. You don't want them to collapse. The bottles won't hold pressure very long, though (a couple years). They have a fairly high permeabilty to air. Use the thickest, biggest bottles you can. It's really a rowboat and dingy sort of thing.
  13. bpw
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    bpw Senior Member

    When Plastiki was built they dropped a little piece of dry ice in each bottle before putting the cap on to pressurize the bottles.

    Plastic bottles don't pack very space efficiently so you use up lots of space for a bit of flotation.

    On another note...have you every considered just drinking out of the tap? Nothing seems more insane to me than burning fuel to carry little bottles of water around the world.

  14. jeffb957
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    jeffb957 Junior Member

    I drive a tractor trailer all across the southeastern United States. For me to drink out of the tap I'd need a team of plumbers constantly lengthening the pipes. :))
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