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Thread: A skin on frame small Catboat ?

  1. #1
    Join Date
    Mar 2016
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    France
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    Default A skin on frame small Catboat ?

    Good morning,

    I love the shape of catboats, and I am considering building a small one, may be a Tom Cat one.

    But I also like the technique of skin on frame. So, I wonder if it would make sense to build a catboat with a skin on frame structure.

    I know that usually, SOF is best for long and narrow hulls, as stiffness is easier to obtain with such long and narrow hulls. But on the other hand, there are some dinghies using SOF: Plat Montfort built some, or David Gentry proposes a 10' x 4 " dinghy, Annabelle:

    http://gentrycustomboats.com/Annabelle.html




    Therefore I have the impression that it would be possible to built a 11'x 5' or 12 'x 6 ' catboat using SOF technique, obviously with adding certain strengthenings inside the hull.

    But may be it would be not heavy enough for a catboat ? or any other issues ?

    Many thanks for your attention to my "out of the box" thoughts...

  2. #2
    Join Date
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    West Boothbay Harbor, Maine
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    Default Re: A skin on frame small Catboat ?

    I'd think the twisting of the structure near the bow, centerboard box and rudder by a true gaff catboat rig like Tom Cat's would be too much for a skin on frame boat, unless the whole structure were so beefed up that there wouldn't be much weight savings. Just a guess.
    "It's a pirate's life for me. Savvy??"

  3. #3
    Join Date
    Sep 2007
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    Northeast
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    Default Re: A skin on frame small Catboat ?

    I know that Dave Gentry is considering a SOF Catboat. The boat in the image above, as you say, is one of his designs (Annabelle) which is after a Chapelle design.

    Brian Schulz of Cape Falcon Kayak also built a fairly substantial sailing dinghy for a trip to Baja, Mexico. He's got a SOF version of a Delaware Ducker as well.

    As Dave mentions, you really need to think of the torsional forces applied to an SOF hull from the mast, daggerboard/centerboard and rudder. The forces can be up there, but there should still be some weight savings if the design is well thought out. The use of ply, laminations and box structure helps along with curvature of stringers and other forms of diagonal frame bracing - much like Platt Monfort's designs.
    "The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails."
    -William A. Ward



  4. #4
    Join Date
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    Charlottesville, Virginia - USA
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    2,004

    Default Re: A skin on frame small Catboat ?

    Quote Originally Posted by PierreDesvaux View Post
    So, I wonder if it would make sense to build a catboat with a skin on frame structure.
    Yes.
    And, what Craig said. Considerable weight savings, though. And time, and money, too (not including the sailing bits).
    Most of my SOF sailing boats have the mast right up front, and they have turned out very well. A lot of thought goes into it, though.

    My catboat is is currently on the drawing board, not just under consideration . . . .

    Feel free to email me if you have questions: GentryCustomBoats@yahoo.com

    Dave
    Last edited by DGentry; 01-09-2018 at 09:00 PM.

  5. #5
    Join Date
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    Cushing, Maine
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    3,334

    Default Re: A skin on frame small Catboat ?

    Brian's Baja boat as an open boat with reiforcments had torsional issues. I worked with him on the ducker and what seemed to work pretty well is putting a plywood deck on it, and running the dagger board trunk through the deck the way some of the old ones did.
    Ben Fuller
    Ran Tan, Liten Kuhling, Tipsy, Tippy, Josef W., Merry Mouth, Imp, Macavity, Look Far, Flash and a quiver of other 'yaks.
    "Bound fast is boatless man."

  6. #6
    Join Date
    May 2009
    Location
    Vienna, Austria
    Posts
    554

    Default Re: A skin on frame small Catboat ?

    Not a catboat, but a nice SOF sailing dinghy:

    Providence River Boat built by Mark Reuten






    Last edited by flo-mo; 01-09-2018 at 07:28 PM.

  7. #7
    Join Date
    Mar 2016
    Location
    France
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    Default Re: A skin on frame small Catboat ?

    Many thanks for all your answers. And it's great to know that Mr Dave Gentry is working on a SOF catboat! I am extremelly interested, Dave! I will contact you.

    Pierre

  8. #8
    Join Date
    Sep 2011
    Posts
    508

    Default Re: A skin on frame small Catboat ?

    Quote Originally Posted by PierreDesvaux View Post
    Many thanks for all your answers. And it's great to know that Mr Dave Gentry is working on a SOF catboat! I am extremelly interested, Dave! I will contact you.

    Pierre
    And I was shopping small catboats not that long ago. Very interested.

  9. #9
    Join Date
    Dec 2011
    Location
    North East England
    Posts
    1,254

    Default Re: A skin on frame small Catboat ?

    Slightly off topic but this popped in my inbox, shows what sort of stresses a SOF craft can take, just foot for thought

    https://youtu.be/SbjZ2FlEHTA

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