build a sailing catamaran without fin

Discussion in 'Multihulls' started by freeman1, Apr 25, 2012.

  1. freeman1
    Joined: Apr 2012
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    freeman1 Junior Member

    I am going to build my first sailing catamaran. I plan to use 2 inflatable pontoon as the hull. It's hard to install fin or something like that on the bottom of the pontoon. So my question is if there is no fin or something work as a heel, can I keep the boat on track without sideslipping? Are there any other problems I will run into?
     
  2. Corley
    Joined: Oct 2009
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    Corley epoxy coated

    I've seen some catamarans with a daggerboard case to hold a daggerboard (your fin) mounted in the tramp between the hulls (the Arrow catamaran comes to mind) you will definetly need some form of leeway resistance or you will go sideways rather than forward on any point of sail except directly down wind, a centrally mounted rudder would be a good idea too so you have some ability to control your direction. There are some negatives since the fins will be surface piercing they will be less efficient than a hull mounted solution but they should still do the job.
     
  3. freeman1
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    freeman1 Junior Member

    Corley, thank you for your suggestions.
    Another question, what is the best or most durable material for the inflatable floating device? I am going to use it in a small bay.
     
  4. Corley
    Joined: Oct 2009
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    Corley epoxy coated

    Sorry, I've not much experience with inflatable fabrics. I'm sure someone will be along soon with some good suggestions on that front.
     
  5. champ0815
    Joined: Apr 2008
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    champ0815 Senior Member

    Since inflatable catamarans are quite common on the market, there are some manufacturers where you can find reference about the used materials.
    Here's a list of manufacturers.
    For home build I think the problem is in airproofing the pontoons in a reliable way.
     
  6. freeman1
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    freeman1 Junior Member

    Thank you champ0815. The list is really useful. I am not going to make pontoons by myself. I just want to know which kind of pontoon I should buy. So airproofing should not be problem to me:)
     
  7. mydauphin
    Joined: Apr 2007
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    mydauphin Senior Member

    Had an old hobbie cat, it had oversized rudders and asymentrical hulls instead
     
  8. spidennis
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    spidennis Chief Sawdust Sweeper

  9. Doug Lord
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    Doug Lord Flight Ready

    =====================
    Illustration of placement of centerboard on small cat:

    click on image-
     

    Attached Files:

  10. Bruno Froes
    Joined: Apr 2012
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    Location: Porto Seguro, Bahia, Brazil

    Bruno Froes Flower Power Boat

    Will you use neoprene, pvc or hypalon?
    Hey this is my first post in this site, sorry for my english...
     
  11. spidennis
    Joined: Feb 2007
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    spidennis Chief Sawdust Sweeper

    Welcome to the forums Bruno!
    ...... and don't worry about your english, you're doing great!
     
    1 person likes this.
  12. freeman1
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    freeman1 Junior Member

    hi Bruno, I am going to use PVC pontoon, 0.9mm thickness. BTW, ur ENG is better than mine:)
     
  13. DimitriW
    Joined: Jun 2013
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    DimitriW Junior Member

    inflatable sailing catamaran with tubeclamps

    Check out my project/thread: inflatable sailing catamaran with tubeclamps.
    A centreboard is a must indeed, I'm able to tack mine but I still got a lot of drift. I'm going to increase the surface of my centreboard. My float are from neoprene/hypalon, originally from a cataraft but I build a new frame. Without the mast I still use it on white water.
     
  14. spidennis
    Joined: Feb 2007
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    spidennis Chief Sawdust Sweeper

    is your link not there?
     

  15. DimitriW
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    Location: belgium

    DimitriW Junior Member

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