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RE: [bolger] Re: Design With Plywood

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  • kreamer
    A piece of stiff paper of thin cardboard enforces its own just like plywood rules. You can maintain a certain bottom-centerline profile (which curve would be
    Message 1 of 19 , May 4, 2006
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      A piece of stiff paper of thin cardboard enforces its own "just like
      plywood" rules. You can maintain a certain bottom-centerline profile (which
      curve would be planar in the vertical orientation) and a certain planar
      chine curve (with its plane vertical, horizontal, and fore-and-aft, or at
      any other orientation), by fixing (gluing) in the workspace a thin planar
      piece of heavy cardboard with the curve of your choice cut in its edge.

      Then force the paper or cardboard against the rigid card-edge with fingers,
      glue or complementary curves cut in other card-edges. The only rules being
      enforced in this little system are that the paper will (must) act like
      plywood, and the two card-edge curves will be maintained. The edges of the
      paper (representing the plywood) can then be trimmed to a pleasing or
      functional curve. The starting curves, alternatively, can be the shear and
      chine. - Bill



      _____

      From: bolger@yahoogroups.com [mailto:bolger@yahoogroups.com] On Behalf Of
      Christopher C. Wetherill
      Sent: Wednesday, May 03, 2006 4:41 PM
      To: bolger@yahoogroups.com
      Subject: RE: RE: [bolger] Re: Design With Plywood



      I am looking for ways to do it with pencil and paper. I have been playing
      with hull.exe for a while and it's nice, but I like being able to do things
      the non-electric way.

      -----Original Message-----
      From: bolger@yahoogroups.com [mailto:bolger@yahoogroups.com]On Behalf Of
      Bruce Hallman
      Sent: Wednesday, May 03, 2006 3:51 PM
      To: bolger@yahoogroups.com
      Subject: Re: RE: [bolger] Re: Design With Plywood


      > From: "Christopher C. Wetherill" <wetherillc@...>
      > Subject: RE: [bolger] Re: Design With Plywood

      There are two issues,

      (1) the strength/durability of plywood materials, and
      (2) the topology of developed shapes / the curvature of plywood.

      For (2), the development of curved shapes by bending flat sheets,
      you can skip the book theory altogether and experiment directly
      with computer programs that automatically take care of the mathatics
      of bending flat plates.

      I especially like the opensource software FreeShip.
      [Also, I like the Hulls.exe software.] Both of these
      allow you to easily experiment with the bending of flat plates
      into curved surfaces.

      My personal favorite is to print the experimental hulls onto
      thin cardboard, and use sissors and tape to make models.

      After just a little practice you can get from an idea in your head
      to a 3D scale model in about one hour.

      http://www.flickr.com/photos/hallman/71601266/


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      - Pls add your comments at the TOP, SIGN your posts, and snip away
      - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
      (978) 282-1349
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      Yahoo! Groups Links








      Bolger rules!!!
      - NO "GO AWAY SPAMMER!" posts!!! Please!
      - no cursing, flaming, trolling, spamming, respamming, or flogging dead
      horses
      - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
      - Pls add your comments at the TOP, SIGN your posts, and snip away
      - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
      (978) 282-1349
      - Unsubscribe: bolger-unsubscribe@yahoogroups.com
      - Open discussion: bolger_coffee_lounge-subscribe@yahoogroups.com




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      [Non-text portions of this message have been removed]
    • adventures_in_astrophotography
      Hi Bruce, ... Several years ago I used Plyboats, but it never ported quite right to W2K, and since it has a lot of limitations (only two chines, among others),
      Message 2 of 19 , May 4, 2006
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        Hi Bruce,

        ...snip...
        > I also agree that hull.exe is nice. Though, FreeShip
        > has hull.exe beat ten times over when it comes to modeling and
        > visualization, key features when prototyping.

        Several years ago I used Plyboats, but it never ported quite right to
        W2K, and since it has a lot of limitations (only two chines, among
        others), I gave up on it. I've just downloaded Free!ship and look
        forward to giving it a try. One question for you, though, is how
        expanded panel dimensions are output from the program. Do I need
        some other application that can read .dxf files, or can I just print
        out the panel dimensions from Free!ship? Will it translate bulkhead
        locations onto the panels?

        I was thinking of starting with the offsets for Cartoon 40, scaling
        the length at 125% per PCB's suggestion, and getting panel shapes and
        dimensions from the application. Think this will work? If it does,
        it would allow me to assemble the sides and bulkheads, then use a jig
        to hold everything square, rather than making critical measurements
        on the jig, erecting the bulkheads, then spiling the panel shapes.

        > I have the personal theory that to get a boat design 'right' you
        > need to go through many many itierations by trial and error.
        ...snip...

        I agree, and think it's true even using the software tools
        available. Using Plyboats, I made many cardboard models of different
        hull shapes, including a lot of sharpies and box-keel designs. It
        was always interesting to see just how bad a model could look when
        the wire-frame in the software looked so good. Slab-side sharpies in
        particular can look fine on the screen, but not so great in "the
        flesh." Part of the problem was Plyboats' limitation of fixing the
        lowest point of the sheer at the point of maximum beam.

        Jon Kolb
        www.kolbsadventures.com/boatbuilding_index.htm
      • Bruce Hallman
        ... I am not the best person to answer that question, as I have not kept up with Freeship since November of 2005. At that point in time, the expanded panel &
        Message 3 of 19 , May 4, 2006
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          > forward to giving it a try. One question for you, though, is how
          > expanded panel dimensions are output from the program.

          I am not the best person to answer that question, as I have not kept
          up with Freeship since November of 2005. At that point in time, the
          expanded panel & bulkhead dimensions was 'wishlisted' for software
          development, and exporting to Autocad and a plotter was the best choice.

          Check here:

          http://groups.yahoo.com/group/Freeship_HTandT_Group

          or the Sourceforge Freeship pages.
        • Bruce Hallman
          ... I should have looked before clicking send but the new version of Freeship, according to the website, has the new feature Export boundary coordinates of
          Message 4 of 19 , May 4, 2006
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            > > forward to giving it a try. One question for you, though, is how
            > > expanded panel dimensions are output from the program.

            I should have looked before clicking 'send' but the new version of
            Freeship, according to the website, has the new feature

            "Export boundary coordinates of developed plates to textfile"

            Which seems to fit the bill.

            http://www.freeship.org/
          • Michael Collins
            Chris, I ve had some pretty interesting results using arcs or arches. Arcs can be manipulated geometrically because their explicit mathematical expression is
            Message 5 of 19 , May 4, 2006
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              Chris,
              I've had some pretty interesting results using arcs or arches. Arcs can
              be manipulated geometrically because their explicit mathematical
              expression is relatively simple compared to NURBS. Arcs are simple to
              loft. All you need to know is the radius of curvature and the
              vertual center of radius. Using a compass or a string, you can draw
              your arc.

              I started using arcs as a means of analyzing other designers' work. For
              example, looking at Phil Bolger's Tortis and Brick in the profile and
              using the waterline as the chord, you see an approximate arc with a
              camber of about 10% of the chord below the water line. I reduced this
              arc to a single number, expressed as the arc Tan ( Camber/ (1/2
              chord)). By looking at several designs, I found that an arc of about 10
              degrees in the profile of the canoe body is characteristic of a
              relatively slow boat capable of carrying a large load.

              If chord is 10.7639 units in length, camber is 1.0, then I would call
              this a 10.5258 degree arc. By naming it in degrees it is easier to
              visuallize, since the angle is close to the entry angle.

              These arcs' geometry can be easily manipulated with a calculator - Easy
              to design with and loft in cardstock or plywood. I use a spreadsheet
              and a caculator for complex designs. The camber of an arc in a plywood
              pannel can be established from the arc in the profile and the angle of
              the pannel from the vertical. For example, say you choose the arc for
              the profile view, yet the topside is flared out 6 degrees. The profile
              arc can then be rotated through 6 degrees using triginometry to find the
              camber of the arc required on the plywood pannel. Now, you need to
              know the chord for the arc in the plywood pannel.

              Say you have a plan view with an arch for the side of a scow. This
              waterline arc effects the same pannel we were just discussing. This
              time we rotate the plan view arc until it's camber is perpendicular to
              the camber of the arc we just rotated from the profile. The length of
              the perimeter of the plan view arch rotated will give you the length of
              the chord you would need to loft the pannel for the topside.

              Sorry if this is confusing. It seems a bit complex to be describing by
              text. Hopefully it gives you some idea about the concept of designing
              with arcs. I'll try answering questions about the technique if you have
              any.

              Michael Collins

              >


              [Non-text portions of this message have been removed]
            • Michael Collins
              Chris, I ve had some pretty interesting results using arcs or arches. Arcs can be manipulated geometrically because their explicit mathematical expression is
              Message 6 of 19 , May 5, 2006
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                Chris,
                I've had some pretty interesting results using arcs or arches. Arcs can
                be manipulated geometrically because their explicit mathematical
                expression is relatively simple compared to NURBS. Arcs are simple to
                loft. All you need to know is the radius of curvature and the
                vertual center of radius. Using a compass or a string, you can draw
                your arc.

                I started using arcs as a means of analyzing other designers' work. For
                example, looking at Phil Bolger's Tortis and Brick in the profile and
                using the waterline as the chord, you see an approximate arc with a
                camber of about 10% of the chord below the water line. I reduced this
                arc to a single number, expressed as the arc Tan ( Camber/ (1/2
                chord)). By looking at several designs, I found that an arc of about 10
                degrees in the profile of the canoe body is characteristic of a
                relatively slow boat capable of carrying a large load.

                If chord is 10.7639 units in length, camber is 1.0, then I would call
                this a 10.5258 degree arc. By naming it in degrees it is easier to
                visuallize, since the angle is close to the entry angle.

                These arcs' geometry can be easily manipulated with a calculator - Easy
                to design with and loft in cardstock or plywood. I use a spreadsheet
                and a caculator for complex designs. The camber of an arc in a plywood
                pannel can be established from the arc in the profile and the angle of
                the pannel from the vertical. For example, say you choose the arc for
                the profile view, yet the topside is flared out 6 degrees. The profile
                arc can then be rotated through 6 degrees using triginometry to find the
                camber of the arc required on the plywood pannel. Now, you need to
                know the chord for the arc in the plywood pannel.

                Say you have a plan view with an arch for the side of a scow. This
                waterline arc effects the same pannel we were just discussing. This
                time we rotate the plan view arc until it's camber is perpendicular to
                the camber of the arc we just rotated from the profile. The length of
                the perimeter of the plan view arch rotated will give you the length of
                the chord you would need to loft the pannel for the topside.

                Sorry if this is confusing. It seems a bit complex to be describing by
                text. Hopefully it gives you some idea about the concept of designing
                with arcs. I'll try answering questions about the technique if you have
                any.

                Michael Collins



                Christopher C. Wetherill wrote:

                > I am looking for ways to do it with pencil and paper. I have been playing
                > with hull.exe for a while and it's nice, but I like being able to do
                > things
                > the non-electric way.
                >
                > -----Original Message-----
                > From: bolger@yahoogroups.com [mailto:bolger@yahoogroups.com]On Behalf Of
                > Bruce Hallman
                > Sent: Wednesday, May 03, 2006 3:51 PM
                > To: bolger@yahoogroups.com
                > Subject: Re: RE: [bolger] Re: Design With Plywood
                >
                >
                > > From: "Christopher C. Wetherill" <wetherillc@...>
                > > Subject: RE: [bolger] Re: Design With Plywood
                >
                > There are two issues,
                >
                > (1) the strength/durability of plywood materials, and
                > (2) the topology of developed shapes / the curvature of plywood.
                >
                > For (2), the development of curved shapes by bending flat sheets,
                > you can skip the book theory altogether and experiment directly
                > with computer programs that automatically take care of the mathatics
                > of bending flat plates.
                >
                > I especially like the opensource software FreeShip.
                > [Also, I like the Hulls.exe software.] Both of these
                > allow you to easily experiment with the bending of flat plates
                > into curved surfaces.
                >
                > My personal favorite is to print the experimental hulls onto
                > thin cardboard, and use sissors and tape to make models.
                >
                > After just a little practice you can get from an idea in your head
                > to a 3D scale model in about one hour.
                >
                > http://www.flickr.com/photos/hallman/71601266/
                >
                >
                > Bolger rules!!!
                > - NO "GO AWAY SPAMMER!" posts!!! Please!
                > - no cursing, flaming, trolling, spamming, respamming, or flogging dead
                > horses
                > - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
                > - Pls add your comments at the TOP, SIGN your posts, and snip away
                > - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
                > (978) 282-1349
                > - Unsubscribe: bolger-unsubscribe@yahoogroups.com
                > - Open discussion: bolger_coffee_lounge-subscribe@yahoogroups.com
                > Yahoo! Groups Links
                >
                >
                >
                >
                >
                >
                >
                >
                > Bolger rules!!!
                > - NO "GO AWAY SPAMMER!" posts!!! Please!
                > - no cursing, flaming, trolling, spamming, respamming, or flogging
                > dead horses
                > - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
                > - Pls add your comments at the TOP, SIGN your posts, and snip away
                > - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930,
                > Fax: (978) 282-1349
                > - Unsubscribe: bolger-unsubscribe@yahoogroups.com
                > - Open discussion: bolger_coffee_lounge-subscribe@yahoogroups.com
                >
                >
                >
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              • moose2much
                Hello Everybody, I have tried several of the DXF viewers and could not get any to work. They all seemed to be teasers for paid products. The best results I ve
                Message 7 of 19 , May 6, 2006
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                  Hello Everybody,

                  I have tried several of the DXF viewers and could not get any to
                  work. They all seemed to be teasers for paid products. The best
                  results I've had so far is with OpenOffice Draw available free from
                  www.OpenOffice.Org I need to work with it more. Started working with
                  Plyboats and then FreeShip.

                  Somehow I was able to make Plyboats work in XPpro and print to a
                  parallel laser printer. Even have an icon on the desktop that works.

                  From and Plyboats Email to Ray Clark:

                  I had some problems with the DEMO not accepting mouse and cursor
                  movement when I tried to run the program from the XP command promp.
                  I extracted the ZIP some other way in XP, maybe using XP's extractor
                  and an icon was placed on the desktop and the program now works.
                  This may help if someone else has the same problem

                  Plyboats running in whatever mysterious way actually takes much
                  more time to execute calculations than FreeShip.

                  Roger Van Arnam
                  Micanopy Beach Florida


                  --- In bolger@yahoogroups.com, "adventures_in_astrophotography"
                  <jon@...> wrote:
                  >
                  > Hi Bruce,
                  >
                  > ...snip...
                  > > I also agree that hull.exe is nice. Though, FreeShip
                  > > has hull.exe beat ten times over when it comes to modeling and
                  > > visualization, key features when prototyping.
                  >
                  > Several years ago I used Plyboats, but it never ported quite right
                  to
                  > W2K, and since it has a lot of limitations (only two chines, among
                  > others), I gave up on it. I've just downloaded Free!ship and look
                  > forward to giving it a try. One question for you, though, is how
                  > expanded panel dimensions are output from the program. Do I need
                  > some other application that can read .dxf files, or can I just
                  print
                  > out the panel dimensions from Free!ship? Will it translate
                  bulkhead
                  > locations onto the panels?
                  >
                  > I was thinking of starting with the offsets for Cartoon 40, scaling
                  > the length at 125% per PCB's suggestion, and getting panel shapes
                  and
                  > dimensions from the application. Think this will work? If it
                  does,
                  > it would allow me to assemble the sides and bulkheads, then use a
                  jig
                  > to hold everything square, rather than making critical measurements
                  > on the jig, erecting the bulkheads, then spiling the panel shapes.
                  >
                  > > I have the personal theory that to get a boat design 'right' you
                  > > need to go through many many itierations by trial and error.
                  > ...snip...
                  >
                  > I agree, and think it's true even using the software tools
                  > available. Using Plyboats, I made many cardboard models of
                  different
                  > hull shapes, including a lot of sharpies and box-keel designs. It
                  > was always interesting to see just how bad a model could look when
                  > the wire-frame in the software looked so good. Slab-side sharpies
                  in
                  > particular can look fine on the screen, but not so great in "the
                  > flesh." Part of the problem was Plyboats' limitation of fixing the
                  > lowest point of the sheer at the point of maximum beam.
                  >
                  > Jon Kolb
                  > www.kolbsadventures.com/boatbuilding_index.htm
                  >
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