Skin-on-frame scow

Discussion in 'Boat Design' started by hospadar, Feb 21, 2012.

  1. ancient kayaker
    Joined: Aug 2006
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    Location: Alliston, Ontario, Canada

    ancient kayaker aka Terry Haines

    A couple of notes FWIIW.

    There may be a confusion of terms: "flare" describes an outward curve in the hull below the sheerline at the bow - it helps deflect water out of the boat; on a SOF it requires a saddle surface and flexible skin material. I don't know the correct boating term for the angle of the outward slope but I call it the "flare angle" . . .

    In your design, bear the following points in mind:

    For a multiple build lots of temporary built-up or ply frames form part of a permanent building mold but for a one-off boat it is simpler and more economical to have fewer and embed them in the boat. In a sailboat these frames can be used distribute the concentrated sailing forces from the mast to the centerboard or daggerboard and to the gunnel and seats to support the crew's weight.

    The forces on the sail balanced by the offset weight of the crew develops a twisting force. In a fully-decked boat the deck and hull form a closed structure which resists twisting. In an open boat this is harder to achieve, especially in a SOF with its thinner skin. While standing rigging helps to stiffen a boat, it gets on the way and most sailors prefer a free-standing mast in a small boat. A fore-and-aft closed box structure can be located under the side decks - if the boat has them - or the seats. A fabric skin over an open frame helps a bit but a better job is done using diagonal stiffeners so all the open shapes become triangles. A radio mast illustrates this principle very well . . .
     
  2. hoytedow
    Joined: Sep 2009
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    Location: North of Cuba

    hoytedow Wood Butcher

    I had to re-post this photo because it made my neck hurt to look at it as it was.

    :)
     

    Attached Files:

  3. hospadar
    Joined: Apr 2011
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    Location: Michigan

    hospadar Junior Member

    Update:
    The boundary waters canoe area called to me, and this skin-on-frame project turned into a canoe.

    I think I will still build a little sailboat of approximately the same dimensions, but using 1/4" underlayment ply, as I suspect that will be more suited to the partyboating and inland sailing I want to do in it (and also just to mix up my summer boat projects a bit).

    Anyways, the canoe is coming along great, all the stringers are on forms right now and awaiting ribs which will probably start this weekend.
     
  4. Collin
    Joined: Nov 2011
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    Location: Olympia, WA

    Collin Senior Member

    The luan stuff is pretty bad for longevity. If you leave it in the water or out in the weather, it can delaminate in a season or two
     

  5. Easy Rider
    Joined: Oct 2009
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    Location: NW Washington State USA

    Easy Rider Senior Member

    Little Peter
    A punt designed by Atkin seems like just about exactly what you want.
    Length 12'2" X 3'10". Very nice lines for a punt and plenty of rocker.
    See it at
    Atkin Boat Plans (atkinboatplans.com)
    It has everything but the large radius chine.

    Easy Rider
     
    1 person likes this.
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