Pontoon build

Discussion in 'Boat Design' started by C-mack, Aug 6, 2013.

  1. C-mack
    Joined: Jan 2010
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    Location: Dallas, Pa.

    C-mack Boat Dreamer

    Question when making pontoons out of wood does the interior space need to have vent? what if the interior space was filled with foam?... thinking of making some kind of craft with pontoons
    Thanks
    Chaz
     
  2. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    You can make very effective pontoons of wood. You should consider saturating the interior with epoxy formulated specifically for that purpose., See WEST system or similar suppliers. You must ventilate the interior of your pontoon even if it has a saturation water barrier. Not just one vent port, use two or more with at least one at or near each end.

    Make the ports big enough and you will have the advantage of extra storage space in the pontoons. When the boat is not in use, leave the ports open so that the interiors can ventilate the condensation that is sure to collect inside the hulls.

    Foam is not needed if the build is structurally sound. Foam will eventually cause trouble. It will almost surely become waterlogged over time. That is bad news for the wood that it supporting the foam. In addition the foam containing moisture will increase the weight of the boat.

    The only argument for foam is as insurance against sinking in case you hole the boat badly. If you use it, do not use poured in place foam.
     
  3. C-mack
    Joined: Jan 2010
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    Location: Dallas, Pa.

    C-mack Boat Dreamer

    Thanks for the info...I will try only something for a single person for a local lake... but in the future I have a larger project of at least 24' where there will be a narrow center hull, say 4' beam and then two smaller pontoon to keep the center upright... A triangle shape thingy.... I love low H.P. / high thrust outboards to move across the water....
     
  4. rasorinc
    Joined: Nov 2007
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    Location: OREGON

    rasorinc Senior Member

    C-mack, I, also would never recommend poured foam anywhere. I do have a supplier of strofoam used for floating docks, etc and they can cut it to any shape you want,
    cyclinders,triangles--what ever and in all lengths. I've had this stuff under a floating dock for 36 years now and no problems except a few musk rat bites. Never absorbs water. And yes, Ventilate well......
     
  5. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    When you are ready to do the bigger one, why do it as a trimaran? If you like low power (so do I ) then you will want to minimize wetted surface as much as is practical. Other designs may be better in that regard.


    For a 24 footer,to be moved with low power, a four foot beam main hull is pretty fat. You will need to ponder this and wet surface characteristics at length before you go for it.
     
  6. C-mack
    Joined: Jan 2010
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    Location: Dallas, Pa.

    C-mack Boat Dreamer

    Thanks for the info on the foam....I'm a home depot rigid foam kind of guy...used a lot of it around foundations....
    The 4' beam is just an idea really need a 30" beam since that is where I would walk thru it's length....It all started when I saw a freight canoe and said :idea:MMMMM!
     

  7. El_Guero

    El_Guero Previous Member

    30" + 12" + 12" = 54" .... The price of a tri is extra beam you cannot walk in, and the added resistance from the water wake between the hulls.
     
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