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Thread: Lapstrake flat bottom / deadrise

  1. #1
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    Default Lapstrake flat bottom / deadrise

    Quote Originally Posted by djtil View Post
    The picture quoted above showed up in a thread yesterday about the 2010 Mystic WBS. The boat in the background looks like lapstrake on a flat bottom skiff. I suppose this was how most skiffs were built before plywood. Probably also true of deadrise skiffs and sharpies. In modern context, would this be done with a glued-lap approach? If the boat would live on a trailer, that is... And is there any reason other than old-timey aesthetics to go this route?

  2. #2
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    Default Re: Lapstrake flat bottom / deadrise

    ^ The absence of framing tells us that it most probably is glued lap plywood.
    Reasons for why, aesthetics, easy to keep clean and paint, no worries about nail sickness and drying shakes.
    It really is quite difficult to build an ugly wooden boat.

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  3. #3
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    Default Re: Lapstrake flat bottom / deadrise

    The advantage to lapstrake above the chine, vs. a single piece of plywood, is the topsides do not have to be developable surfaces. And glued lapstrake has all the advantages Nick mentioned.

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    Default Re: Lapstrake flat bottom / deadrise

    Depending on the design, there may be no compelling reason for glued lap vs a single sheet of ply -- however I vastly prefer the glued lap for both looks and strength. Redmond's Whisp is a good example, where the faux glued lap sides are built flat on the ground, then installed just as a single piece of ply would be used. I've even teased Mik about doing something similar for his Goat Island Skiff, as his Australian friends think that all Yank-built boats seem to require lapstrake hulls. ;-)
    Last edited by Thorne; 12-15-2016 at 05:04 PM.
    "The enemies of reason have a certain blind look."
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  5. #5
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    Default Re: Lapstrake flat bottom / deadrise

    Yes, Thorne, it seems like lapstrake sides do a world of good toward making an otherwise slab-sided hull look less slabby.

  6. #6
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    Default Re: Lapstrake flat bottom / deadrise

    I use flat panel bottoms and lapstrake sides a lot, but the sides are very rounded, the entry at water level very fine, and the boats have a lot more rocker in the bottom than the skiff above.
    It would not be possible to build the shapes I use with solid wood planks unless they were scarfed to get the quite extreme edge curves that they need to follow the planking line, which is easy with plywood.

    John Welsford
    An expert is but a beginner with experience.

  7. #7
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    Default Re: Lapstrake flat bottom / deadrise

    Also an added advantage of lapped sides is the "stringer effect" built in, that one sheet topsides would probably need.

  8. #8
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    Default Re: Lapstrake flat bottom / deadrise

    Regarding J.W.'s statement below, I am going to pour through his designs. I am where the saltwater
    deepens slowly, as one walks from the shore outward, toward the middle of the G.O.M. Referring to
    the picture at the top of this thread, my very first thought was, that the flat bottomed boat would be
    immeasurably MORE BEAUTIFUL, if it had SIDES shaped exactly as the boat in the forefront of the picture!
    Quote Originally Posted by john welsford View Post
    I use flat panel bottoms and lapstrake sides a lot, but the sides are very rounded, the entry at water level very fine, and the boats have a lot more rocker in the bottom than the skiff above.
    It would not be possible to build the shapes I use with solid wood planks unless they were scarfed to get the quite extreme edge curves that they need to follow the planking line, which is easy with plywood.

    John Welsford
    Jack

  9. #9
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    Default Re: Lapstrake flat bottom / deadrise

    Suggest that you try a flat bottomed boat on the water before building one!

  10. #10
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    Lightbulb Re: Lapstrake flat bottom / deadrise

    Thank you neil.henderson for: "Suggest that you try a flat bottomed boat on the water before building one!"
    Due to our saltwater shallowness, 12" or less draft is a great feature. I am hoping that I can beach a boat of
    about 17-19 feet with ease, the boat looking like the photo I've attached.
    Attached Images Attached Images
    Jack

  11. #11
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    Default Re: Lapstrake flat bottom / deadrise

    One challenge for glued lap is getting the kind of flare that one might want say the way Pete Culler did it in his skiffs which certainly can have a solid ply bottom. Don't know if anyone has tried to do a Culler skiff in glued lap.

    Some boats have used the tops of a lap for seat support.

    Glued lap generally doesn't have and need much interior structure. There is no riser which makes maintenance easy. At the same time a riser has lots of other uses, besides stiffening and seat support. Places to stow oarlocks, tie on a gear hammock, places to attach handy short lanyards, lash in buoyancy bags, a rail for a removable seat, tie in a gear bag, anchor bag. Just thinking about the riser useage in various boats around the door yard here.

  12. #12
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    Default Re: Lapstrake flat bottom / deadrise

    Here's a flat bottomed, round sided beauty by J. Welsford (called PENGUIN):
    Attached Images Attached Images
    Jack

  13. #13
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    Default Re: Lapstrake flat bottom / deadrise

    Quote Originally Posted by Thorne View Post
    Depending on the design, there may be no compelling reason for glued lap vs a single sheet of ply -- however I vastly prefer the glued lap for both looks and strength. Redmond's Whisp is a good example, where the faux glued lap sides are built flat on the ground, then installed just as a single piece of ply would be used. I've even teased Mik about doing something similar for his Goat Island Skiff, as his Australian friends think that all Yank-built boats seem to require lapstrake hulls. ;-)
    Hmmmmmmmmmm - Iain Oughtred is an Aussie living on Skye................

  14. #14
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    Default Re: Lapstrake flat bottom / deadrise

    AdvenJack:
    If the tides and currents in Tampa Bay are anything like Charleston Harbor, think carefully about beaching. Your boat could be floating away or your waiting fo the next high tide to launch. LOL!

  15. #15
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    Default Re: Lapstrake flat bottom / deadrise

    Arlc, Thanks for the friendly advise! You're a good internet buddy!
    Jack

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