• Flatten/develop plank shapes from lofted offsets

    From Dale Rogers@21:1/5 to All on Mon Sep 7 17:34:11 2015
    Hi folks, is there a 'paper' way to develop the 'flat' plank shapes from offsets and lofted lines?

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  • From bruceinbangkok@nowhere.org@21:1/5 to dale@madethings.com.au on Tue Sep 8 18:13:19 2015
    On Mon, 7 Sep 2015 17:34:11 -0700 (PDT), Dale Rogers
    <dale@madethings.com.au> wrote:

    Hi folks, is there a 'paper' way to develop the 'flat' plank shapes from offsets and lofted lines?

    Certainly there is. It is called "spiling". Try
    http://tinyurl.com/p4qymfk
    and click on the first entry - Planking a Carvel planked boat
    which should get you a PDF from the Pennsylvania State University
    or http://www.boat-building.org/learn-skills/index.php/en/wood/making-plank-templates/
    which has a video and instructions.

    there are several other sited on the same page that cover things

    In rough terms, you simply divide the length of each timber (rib) by
    the number of planks you will use and that gives you the width of the
    plank at that station.

    That is not an exact measurement as you likely will have to allow for
    the outgage and perhaps for having to hollow the back of the plank to
    fit a timber.
    --
    Cheers,

    Bruce

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  • From Wayne.B@21:1/5 to bruceinbangkok@nowhere.org on Tue Sep 8 13:29:44 2015
    On Tue, 08 Sep 2015 18:13:19 +0700, bruceinbangkok@nowhere.org wrote:

    On Mon, 7 Sep 2015 17:34:11 -0700 (PDT), Dale Rogers
    <dale@madethings.com.au> wrote:

    Hi folks, is there a 'paper' way to develop the 'flat' plank shapes from offsets and lofted lines?

    Certainly there is. It is called "spiling". Try
    http://tinyurl.com/p4qymfk
    and click on the first entry - Planking a Carvel planked boat
    which should get you a PDF from the Pennsylvania State University
    or >http://www.boat-building.org/learn-skills/index.php/en/wood/making-plank-templates/
    which has a video and instructions.

    there are several other sited on the same page that cover things

    In rough terms, you simply divide the length of each timber (rib) by
    the number of planks you will use and that gives you the width of the
    plank at that station.

    That is not an exact measurement as you likely will have to allow for
    the outgage and perhaps for having to hollow the back of the plank to
    fit a timber.

    ===

    Good links Bruce, thanks. I would argue however that creating cutting templates on the framing is not quite the same thing as lofting
    dimensions from the plans. There may be a way to do it with computer
    design systems, at least for larger pieces of steel, aluminum or
    tortured plywood.

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  • From Mark Reuten@21:1/5 to Dale Rogers on Tue Sep 8 16:58:22 2015
    On Monday, 7 September 2015 17:34:13 UTC-7, Dale Rogers wrote:
    Hi folks, is there a 'paper' way to develop the 'flat' plank shapes from offsets and lofted lines?

    There is but it may not always be perfectly successful. It's referred to as an expansion. it works best on panels that do not have much twist to them or in which you can determine a common point or plane in which the twist occurs. It is best done from a
    full scale lofting. It's pretty strait forward in the case of a curved transom for instance but becomes trickier when you get into planking.
    Howard Chapelle covers it in "Boatbuilding" in his portion on lofting and also in which he applies the plank expansion technique to a grand banks dory lines. For plywood panels, John Teal covers "conical expansions" in his book "Designing Small Craft".
    Paul Gartside also discusses conical expansions in a Watercraft Magazine article and explains his builders method which utilizes a simple station mould scale half model.

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  • From bruceinbangkok@nowhere.org@21:1/5 to waynebatrecdotboats@hotmail.com on Wed Sep 9 12:25:28 2015
    On Tue, 08 Sep 2015 13:29:44 -0400, Wayne.B
    <waynebatrecdotboats@hotmail.com> wrote:

    On Tue, 08 Sep 2015 18:13:19 +0700, bruceinbangkok@nowhere.org wrote:

    On Mon, 7 Sep 2015 17:34:11 -0700 (PDT), Dale Rogers >><dale@madethings.com.au> wrote:

    Hi folks, is there a 'paper' way to develop the 'flat' plank shapes from offsets and lofted lines?

    Certainly there is. It is called "spiling". Try
    http://tinyurl.com/p4qymfk
    and click on the first entry - Planking a Carvel planked boat
    which should get you a PDF from the Pennsylvania State University
    or >>http://www.boat-building.org/learn-skills/index.php/en/wood/making-plank-templates/
    which has a video and instructions.

    there are several other sited on the same page that cover things

    In rough terms, you simply divide the length of each timber (rib) by
    the number of planks you will use and that gives you the width of the
    plank at that station.

    That is not an exact measurement as you likely will have to allow for
    the outgage and perhaps for having to hollow the back of the plank to
    fit a timber.

    ===

    Good links Bruce, thanks. I would argue however that creating cutting >templates on the framing is not quite the same thing as lofting
    dimensions from the plans. There may be a way to do it with computer
    design systems, at least for larger pieces of steel, aluminum or
    tortured plywood.

    Well, you did say "plank" which does infer the exterior covering of a
    hull :-)

    If you are building a smallish plywood boat then it is possible to
    developer planking straight from the design, and in fact I had a
    simple boat design application that would do it automatically. That
    application was called "Hulls" and was a freebe. I used it to make sew
    and glue small boats and it certainly worked well on small - 12 - 20
    ft. dinghy sort of things, where if it doesn't quite fit you just glob
    a bunch of epoxy in the hole.

    But if you are talking about doing it on a larger boat than I think I
    would be a bit apprehensive about cutting planking directly from a,
    say 3 ft x 3 ft. drawing and expect them to fit perfectly on a, say 35
    ft. boat. And if you are talking about "tortured" planking then it
    adds the element of how much you are torturing them :-)

    Again, if you have a hull design application it is certainly possible
    for the software to accomplish the job, but that also means that every
    thing you cut to shape and fit has to be exact also. If, for example,
    you pre-cut your planking to exactly fit on a specific curve and than
    cut one of the formers, ribs, etc. a tiny bit over size, or get the
    curve a tiny bit wrong... the plank doesn't fit.
    --
    Cheers,

    Bruce

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