Building a small trimaran

Discussion in 'Boat Design' started by Samhill, Mar 15, 2013.

  1. Samhill
    Joined: Mar 2013
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    Samhill Junior Member

    I'm contemplating building a small trimaran as a fast camp cruiser in Long Island Sound. I have a set of Supercat 17 hulls to use and am considering a Yngling for the center hull.
    I'd be essentially recreating the Soling Trimaran on a slightly smaller scale.

    Being that this would be my first build and having no experience with Trimarans,
    I would appreciate any advice you might have.

  2. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    Check out the "Multihulls" thread of the site-- good luck and welcome to the forum.
  3. Submarine Tom

    Submarine Tom Previous Member



    Do you have any pictures of what you're proposing showing spacing and positioning?
  4. Samhill
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    Samhill Junior Member

    No pictures yet, it is still theory. I am concerned primarily about two things...
    I am concerned about the weight and wetted surface for the center hull.

    Because of the consistently inconsistent choppy conditions of Long Island Sound, I would prefer to cruise with the center hull above the water.
    The Supercat hulls are very buoyant, and with sufficient cross beams, they should support the boat on a heel, but the Yngling hull could possibly be too heavy or have a greater than necessary wetted area to easily facilitate a full heel.

    I'm considering a Yngling, because not only have I found a cheap one, but it is only a few feet longer than the Supercat 17 hulls enabling a hull to amas ratio similar to what I have seen in production tri's.

  5. Skyak
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    Skyak Senior Member

    Personally I would build my own simple main hull. The soling is too big, heavy, weak, and tall. The soling will float high once the keel is off, so the waterline will be short wide and round. Take a look at where the crossbeams will need to be mounted, you might find that the large hull will be divided into small useless spaces once you mount and support the beams. I think the soling is made of polyester FG -modifying or attaching to it will be poor (if the hull is epoxy FG it wouldn't be bad -Read the Gougon bros. west system book about how to do this). I would want a transom hung kick-up rudder and a dagger board for shallow draft -major mods for a soling. I also disagree that the 26ft soling is a good match to 17ft supercat amas -proper size would be 17 to 21ft long with 2 ft max waterline beam and less than 400 lb.

    The main hull of a tri can be a simple flat bottom skiff with strong reinforcement between the beams. A tremolino would be perfect with the supercat 17 hulls.

    Attached Files:

  6. Samhill
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    Samhill Junior Member

    Thanks for the advice Skyak, you make some very goods points.
    I was considering a Yngling hull rather than a Soling.
    The Yngling is a 20ft boat so it would be closer in size to the Supercat 17 hulls.
    There have been successful Soling conversions though using Tornado hulls.

    I'll review the Tremolino specs, I hadn't seen those before
  7. upchurchmr
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    upchurchmr Senior Member


    Do you want a cruiser or a daysailor?

    For a daysailor use a Tornado main hull.
    For a cruiser perhaps the Yngling will work well, but it will be a lot of work for something no one else will want.
    The Supercat hulls may not have enough strength when you are flying the Yngling (minus keel) and the other supercat hull. Just a thought. The Supercat was not designed for that load. Of course the Tremolino has worked for a long time with Hobie 16 hulls. It goes faster with bigger amas.

  8. luckystrike
    Joined: Feb 2010
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    luckystrike Power Kraut


    I agree, check out the multihulls section of boatdesign net carefully. There are hidden a lot of trimaran projects using beachcat hulls as amas.

    A yingling is no good option as mainhull. As said, it is designed as a keelboat, to round in keelline, to much waterline beam.

    A special designed multihull mainhull will work better. If you choose a simple one, the build is fast an no more complicated or more expensive than a yingling conversion.

    Check out Richard Woods "Strike" Trimarans, or this one from my drawing board.

    Best Regards, Michel
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