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Re: Commonsense Skiff

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  • gbship
    Graeme: Thanks. Found them. That beach cruiser is interesting. I m looking for womething that can be built of foam/epoxy/glass instead of ply/glass for an
    Message 1 of 20 , Jul 1, 2005
      Graeme:

      Thanks. Found them. That beach cruiser is interesting. I'm looking
      for womething that can be built of foam/epoxy/glass instead of
      ply/glass for an ultra-light boat, hopefully in the 70-80 pound
      range. Candidates are these two boats, Michalak's Woodbo, and maybe
      Gypsy, with some modifications (I want a reefing sail and room to
      sleep on board under a boom tent. Not sure the Beach Cruiser could be
      done light enough, but it sure is a seductive design.

      Gary

      --- In bolger@yahoogroups.com, "graeme19121984" <graeme19121984@y...>
      wrote:
      > Gary,
      > if you look in this group's files under Perfect Skiff, or here:
      >
      > http://groups.yahoo.com/group/bolger/files/Perfect%20Skiff/
      >
      > The boats here, 'CSD Skiff', and 'Beach Cruiser Concept', are
      great!
      > PCB writes 'BCC' can sail through very rough water, including surf.
      > What's rougher than surf :)?
      >
      > I'm inclined to prefer the 'BCC'. Is it a kind of
      > stretched'n'decked 'Jinni'? (not many images around of 'Jinni',
      > especially plan view, though the design is refered to plenty. Its
      in
      > an old book I've been unable to get yet.)
      >
      > Do you know if PCB proved the concept of 'BCC'? Has done a design
      > (perhaps for the allegedly infamous Woodenboat magazine early
      > 90's "Perfect Skiff Competition")? Or are the compromises (to power
      > etc)in 'CSD Skiff' it?
      >
      > cheers
      > graeme
      >
      > --- In bolger@yahoogroups.com, "gbship" <gbship@c...> wrote:
      > > Does anyone know of a link to pictures/plans for the Commonsense
      > Skiff,
      > > a rowing/sailing/power combo that Bolger drew several years ago?
      > >
      > > Thanks
      > >
      > > Gary Blankenship
    • graeme19121984
      Hi Gary, I just realised from here: (see pp 3 & 9) http://www.boatdesign.com/postings/Files/instbb/ib9.pdf that Jinni is a plumb-sided squareboat. Slightly
      Message 2 of 20 , Jul 1, 2005
        Hi Gary, I just realised from here: (see pp 3 & 9)

        http://www.boatdesign.com/postings/Files/instbb/ib9.pdf

        that "Jinni" is a plumb-sided squareboat. Slightly bigger than "June
        Bug" eh? Pretty. Fast. Camp space for two, a tent that could also
        cover both fore and aft storage compartents without the rainwater
        runs from a mast stepped in the forward well.

        Apparently Bolger mods include solent lug (easier reefing), lee
        boards, and
        Jim Michalak's mods of pivoting lee board/rudder, and balanced lug
        (easier reefing but rainwater dowm mast).

        Pre-glassed foam panels, cut and glued? Easy and quick build; but
        may exceed your 80lbs limit? Wooboo also takes six sheets of ply, I
        think.

        graeme


        --- In bolger@yahoogroups.com, "gbship" <gbship@c...> wrote:
        > Graeme:
        >
        > Thanks. Found them. That beach cruiser is interesting. I'm looking
        > for womething that can be built of foam/epoxy/glass instead of
        > ply/glass for an ultra-light boat, hopefully in the 70-80 pound
        > range. Candidates are these two boats, Michalak's Woodbo, and
        maybe
        > Gypsy, with some modifications (I want a reefing sail and room to
        > sleep on board under a boom tent. Not sure the Beach Cruiser could
        be
        > done light enough, but it sure is a seductive design.
        >
        > Gary
        >
        > --- In bolger@yahoogroups.com, "graeme19121984"
        <graeme19121984@y...>
        > wrote:
        > > Gary,
        > > if you look in this group's files under Perfect Skiff, or here:
        > >
        > > http://groups.yahoo.com/group/bolger/files/Perfect%20Skiff/
        > >
        > > The boats here, 'CSD Skiff', and 'Beach Cruiser Concept', are
        > great!
        > > PCB writes 'BCC' can sail through very rough water, including
        surf.
        > > What's rougher than surf :)?
        > >
        > > I'm inclined to prefer the 'BCC'. Is it a kind of
        > > stretched'n'decked 'Jinni'? (not many images around of 'Jinni',
        > > especially plan view, though the design is refered to plenty.
        Its
        > in
        > > an old book I've been unable to get yet.)
        > >
        > > Do you know if PCB proved the concept of 'BCC'? Has done a
        design
        > > (perhaps for the allegedly infamous Woodenboat magazine early
        > > 90's "Perfect Skiff Competition")? Or are the compromises (to
        power
        > > etc)in 'CSD Skiff' it?
        > >
        > > cheers
        > > graeme
        > >
        > > --- In bolger@yahoogroups.com, "gbship" <gbship@c...> wrote:
        > > > Does anyone know of a link to pictures/plans for the
        Commonsense
        > > Skiff,
        > > > a rowing/sailing/power combo that Bolger drew several years
        ago?
        > > >
        > > > Thanks
        > > >
        > > > Gary Blankenship
      • graeme19121984
        Actually, is the Jinny hull a slightly bigger June Bug , or a re- worked Cold Water Sailboard (Chapter 5 FS)? I ve thought about camper mods to CWS .
        Message 3 of 20 , Jul 1, 2005
          Actually, is the "Jinny" hull a slightly bigger "June Bug", or a re-
          worked "Cold Water Sailboard" (Chapter 5 FS)?

          I've thought about camper mods to "CWS".

          cheers
          graeme


          --- In bolger@yahoogroups.com, "graeme19121984" <graeme19121984@y...>
          wrote:
          > Hi Gary, I just realised from here: (see pp 3 & 9)
          >
          > http://www.boatdesign.com/postings/Files/instbb/ib9.pdf
          >
          > that "Jinni" is a plumb-sided squareboat. Slightly bigger than "June
          > Bug" eh? Pretty. Fast.
        • Chris Lasdauskas
          ... Gary, I forget the details, but a few years ago I sat down and worked out the weight for Gypsy built out of various types of Ply and alternatively from
          Message 4 of 20 , Jul 2, 2005
            gbship wrote:

            > Graeme:
            >
            > Thanks. Found them. That beach cruiser is interesting. I'm looking
            > for womething that can be built of foam/epoxy/glass instead of
            > ply/glass for an ultra-light boat, hopefully in the 70-80 pound
            > range. Candidates are these two boats, Michalak's Woodbo, and maybe
            > Gypsy, with some modifications (I want a reefing sail and room to
            > sleep on board under a boom tent. Not sure the Beach Cruiser could be
            > done light enough, but it sure is a seductive design.
            >
            > Gary


            Gary,
            I forget the details, but a few years ago I sat down and worked out the
            weight for Gypsy built out of various types of Ply and alternatively
            from glassed foam. The foam was heavier than at least the lightest
            (possibly all) ply variation.

            I vaguely recall the issue was getting reasonable penetration protection.

            Chris
          • gbship
            Graeme, I m not sure Jimmi would row as well as the others, although it would be a possibility. It would be a better bet if two of us do this competition
            Message 5 of 20 , Jul 2, 2005
              Graeme, I'm not sure Jimmi would row as well as the others, although it
              would be a possibility. It would be a better bet if two of us do this
              competition instead of me doing it solo. I would tend to think a multi-
              chine like Gypsy or Woodbo would be better, or if it's a sharpie hull,
              it would have to be faily narrow for its length, like the Beach Cruiser.

              Chris: How do you figure scantlings for foam/glass construction? I've
              done some online looking, but haven't found any resources. A friend
              laminated a couple layers of glass on either side of 3/8 inch foam (I
              think that was the thickness) and you could whack it with a hammer
              without damage and it was considerably lighter than a ply sandwich
              would have been. I made some hatches for our Frolic2 of glass over 1/4-
              inch foam and those are reasonably strong, and very light, but not
              strong enough for use for a hull. I have no idea if I should use
              thicker foam, more glass, or both for suitable strength. For that
              matter, if the budget allows, it's possible I'll got to carbon
              fiber/foam, which should be even lighter, but again, I have no idea of
              the suitable scantlings....

              Gary
            • graeme19121984
              Gary, competition changes things. IIRC Tom F Jones in Low Resistance Boats wrote of a
              Message 6 of 20 , Jul 2, 2005
                Gary, "competition" changes things. IIRC Tom F Jones in "Low
                Resistance Boats" wrote of a <100 lbs garvey he once designed for a
                week-or-so long beachcruising race in which boats (solo) had to
                carry all their necessaries, and be able to be beached well above
                high water by their crew without any assistance of any kind each
                night. I liked the idea of that little cute sneakbox style 3/4
                decked cruiser a lot, and swear I would have built one if Jones
                published plans. Its owner loved it and enjoyed lengthy cruises and
                messing about in it for many years. It was no racer though. A wiser
                Jones wrote that if he had to do it again for that type of
                competition he would design something minimumalist canoe like. The
                sailing was not quite as important a factor as lightness and rowing.

                How about an adjusted "Zephyr" for two? length/beam > 6/1. (with
                reduced scantlings? Anhinga at 23'5" has only 0.25" ply sides)

                graeme

                --- In bolger@yahoogroups.com, "gbship" <gbship@c...> wrote:
                > Graeme, I'm not sure Jimmi would row as well as the others,
                although it
                > would be a possibility. It would be a better bet if two of us do
                this
                > competition instead of me doing it solo. I would tend to think a
                multi-
                > chine like Gypsy or Woodbo would be better, or if it's a sharpie
                hull,
                > it would have to be faily narrow for its length, like the Beach
                Cruiser.
                >
                > Chris: How do you figure scantlings for foam/glass construction?
                I've
                > done some online looking, but haven't found any resources. A
                friend
                > laminated a couple layers of glass on either side of 3/8 inch foam
                (I
                > think that was the thickness) and you could whack it with a hammer
                > without damage and it was considerably lighter than a ply sandwich
                > would have been. I made some hatches for our Frolic2 of glass over
                1/4-
                > inch foam and those are reasonably strong, and very light, but not
                > strong enough for use for a hull. I have no idea if I should use
                > thicker foam, more glass, or both for suitable strength. For that
                > matter, if the budget allows, it's possible I'll got to carbon
                > fiber/foam, which should be even lighter, but again, I have no
                idea of
                > the suitable scantlings....
                >
                > Gary
              • Howard Stephenson
                Gary, If you go to: http://boatdesign.net/forums/archive/index.php/t-6334 .. you will find useful guidance on foam/glass scantlings. Following the advice
                Message 7 of 20 , Jul 2, 2005
                  Gary,

                  If you go to:

                  http://boatdesign.net/forums/archive/index.php/t-6334

                  .. you will find useful guidance on foam/glass scantlings. Following
                  the advice there, you should be able to decide what your scantlings
                  would need to be and then compare the calculated weight per unit area
                  with that of a ply skin -- and compare the cost too!

                  Howard

                  --- In bolger@yahoogroups.com, "gbship" <gbship@c...> wrote:> Chris:
                  How do you figure scantlings for foam/glass construction? I've
                  > done some online looking, but haven't found any resources.
                • Chris Lasdauskas
                  ... Gary, as I said it was a few years back, so this may not be right, but I think I used The Elements of Boat Strength for Builders, Designers, and Owners
                  Message 8 of 20 , Jul 2, 2005
                    gbship wrote:
                    >
                    > Chris: How do you figure scantlings for foam/glass construction? I've
                    > done some online looking, but haven't found any resources.

                    Gary, as I said it was a few years back, so this may not be right, but I
                    think I used "The Elements of Boat Strength for Builders, Designers, and
                    Owners" by Dave Gerr (though that is copyright 2000, and I thought I did
                    this in about 1999..., perhaps I used his "The Nature of Boats"), I
                    think I also didn't find much online.

                    > A friend
                    > laminated a couple layers of glass on either side of 3/8 inch foam (I
                    > think that was the thickness) and you could whack it with a hammer
                    > without damage and it was considerably lighter than a ply sandwich
                    > would have been.

                    Which reminds me of this cautionary story from "The Nature of Boats":

                    'A Warning About Being Thin-Skinned

                    'A final word of warning is in order. When using these high-strength
                    fibers and sandwich construction, the skin thickness required for
                    overall —- remember overall -— structural strength can become almost
                    unbelievably thin, even on quite large vessels. This works out well on
                    paper, but what about hitting a floating log? A well-known designer
                    related a story both amusing and worrisome. A local builder of large
                    (90-foot, 27-meter) high-speed sportfishermen proudly showed him an
                    all-Kevlar, foam-sandwich hull panel that he'd used in a couple of
                    recent craft. The builder explained that his computer confirmed the
                    very, very thin skins (on the inside and outside of the foam) were more
                    than up to the job.

                    'To demonstrate his point, the builder took a hammer and wacked at the
                    sample panel mightily. With the hammer bouncing off harmlessly, he
                    offered it confidently to the skeptical architect. Taking the hammer,
                    the architect turned it claw-side down and -— with virtually no force at
                    all -— drove it right through Kevlar, the foam, and out the other side.
                    The builder's face turned white. He had a couple of boats out on the
                    water with this layup. The moral -— there's always a moral -— is that
                    the structural design of high-tech hulls is a complicated business.
                    Before you dash off to build or have built one of these miracle hulls,
                    make sure a good naval architect does a detailed structural analysis.'

                    That's what I was talking about when I mentioned penetration strength.
                    Sure a Gypsy isn't going to hit logs at 30 knots, but the scantlings
                    will already be redeuced in proportion to the speed. You can't let the
                    skins get too thin. 'Too thin' on foam is thinnner than 'too thin' on
                    ply. Avoiding that was where the extra weight came from.

                    Chris
                  • gbship
                    ... strength. ... the ... Thanks everyone for the thought and advice. I should have explained better the use for this boat. It s for an expedition type
                    Message 9 of 20 , Jul 3, 2005
                      >
                      > That's what I was talking about when I mentioned penetration
                      strength.
                      > Sure a Gypsy isn't going to hit logs at 30 knots, but the scantlings
                      > will already be redeuced in proportion to the speed. You can't let
                      the
                      > skins get too thin. 'Too thin' on foam is thinnner than 'too thin' on
                      > ply. Avoiding that was where the extra weight came from.
                      >
                      > Chris

                      Thanks everyone for the thought and advice. I should have explained
                      better the use for this boat. It's for an expedition type competition
                      of around 1,000 miles, give or take, for kayaks and small sailboats.
                      Among the salient features, are you must beach launch your craft (You
                      can use mechanical assistance, but you must carry whatever you use for
                      the entire race), the ability to go under a 9-foot high bridge with 10-
                      foot horizontal clearance, deal with open water and inland waterways
                      churned by powerboat wakes, etc. This race is around the peninsula part
                      of Florida, so at one point, competitors have to go up the St. Mary's
                      river (in S. Georgia) and then portage their boats 40 MILES to the
                      Suwanee. The kayakers balance their boats on a set of wheels, attach
                      the bow to the back of their belt and walk it. They can also tow it
                      with a folding bike -- as long as they carry the bike for the entire
                      race. Obviously this won't work for sailboats, which even in a small
                      size weigh much more. So those comeptitors are allowed to switch to a
                      canoe for the necessary river portions and the portage. You can see the
                      details at Watertribe.com, check the Ultra Florida Challenge section.
                      We're only planning to do the shorter Everglades Challenge in 2006, in
                      our Frolic2, but I'm intrigued with trying the longer race in 2007. My
                      particular itch right now is to wonder if a small sailboat could be
                      built light enough so that switching to the canoe would be unnecessary,
                      even for the portage (which I would do with a bike!).

                      But, alas, I know almost nothing of composite construction, which is
                      why everyone's advice is so helpful and much appreciated. It does no
                      good to have an ultralight hull if it's punctured by a razor sharp
                      shell on an oyster bar, or a cypress knee or mangrove root in the
                      Everglades, or by a rock or log in the Suwanee. The weight concern is
                      why I've been mostly looking at ply instant-type boats in the 125 to
                      150 pound range and wondering if that weight could be cut in half with
                      composite construction. There are intriguing hints. For example, my 25-
                      30 pound solid wood mast on the Rolic2 could be replaced by a carbon
                      fiber spar that would weight less than 10 pounds. In Pete Goss' book
                      about single handed racing around the world, he mentions that the bare
                      hull of his 50 footer could be turned over by 6 husky guys --- about
                      what the 1/2 inch ply/fiberglass bare hull weighs on our 30-footer
                      (which is a Gypsy-type hull).

                      BTW Graeme, thanks for the suggestion of the Zephyr, but I ruled that
                      out because while it is an excellent daysailer and can handle some
                      nasty weather, it doesn't row very well, possibly because the 16-inch
                      sides are too high. (I had one for many years, and was very fond of it.)

                      Gary Blankenship
                    • John B. Trussell
                      There have been various threads wich suggest that PCB doesn t design racing boats. You might take a look at Paul Gartside s web site--His Flashboat is a
                      Message 10 of 20 , Jul 3, 2005
                        There have been various threads wich suggest that PCB doesn't design
                        "racing" boats. You might take a look at Paul Gartside's web site--His
                        Flashboat is a very light, very fast row boat and he has camp cruised around
                        Alaska in it.

                        It appears to me that the rules you described favor a kayak with a sail.
                        I've always thought that a two person rowing boat would do well in this sort
                        of race--the two rowers could alternate and maintain speed more or less
                        continuously; they would also have the ability to row together and buck
                        currents if needed.

                        I'm way too old and decrepit to participate or even enjoy the kind of boat
                        needed for this kind of event, but iy si fun to think about.

                        John T
                        ----- Original Message -----
                        From: "gbship" <gbship@...>
                        To: <bolger@yahoogroups.com>
                        Sent: Sunday, July 03, 2005 7:57 AM
                        Subject: [bolger] Re: Commonsense Skiff


                        > >
                        > > That's what I was talking about when I mentioned penetration
                        > strength.
                        > > Sure a Gypsy isn't going to hit logs at 30 knots, but the scantlings
                        > > will already be redeuced in proportion to the speed. You can't let
                        > the
                        > > skins get too thin. 'Too thin' on foam is thinnner than 'too thin' on
                        > > ply. Avoiding that was where the extra weight came from.
                        > >
                        > > Chris
                        >
                        > Thanks everyone for the thought and advice. I should have explained
                        > better the use for this boat. It's for an expedition type competition
                        > of around 1,000 miles, give or take, for kayaks and small sailboats.
                        > Among the salient features, are you must beach launch your craft (You
                        > can use mechanical assistance, but you must carry whatever you use for
                        > the entire race), the ability to go under a 9-foot high bridge with 10-
                        > foot horizontal clearance, deal with open water and inland waterways
                        > churned by powerboat wakes, etc. This race is around the peninsula part
                        > of Florida, so at one point, competitors have to go up the St. Mary's
                        > river (in S. Georgia) and then portage their boats 40 MILES to the
                        > Suwanee. The kayakers balance their boats on a set of wheels, attach
                        > the bow to the back of their belt and walk it. They can also tow it
                        > with a folding bike -- as long as they carry the bike for the entire
                        > race. Obviously this won't work for sailboats, which even in a small
                        > size weigh much more. So those comeptitors are allowed to switch to a
                        > canoe for the necessary river portions and the portage. You can see the
                        > details at Watertribe.com, check the Ultra Florida Challenge section.
                        > We're only planning to do the shorter Everglades Challenge in 2006, in
                        > our Frolic2, but I'm intrigued with trying the longer race in 2007. My
                        > particular itch right now is to wonder if a small sailboat could be
                        > built light enough so that switching to the canoe would be unnecessary,
                        > even for the portage (which I would do with a bike!).
                        >
                        > But, alas, I know almost nothing of composite construction, which is
                        > why everyone's advice is so helpful and much appreciated. It does no
                        > good to have an ultralight hull if it's punctured by a razor sharp
                        > shell on an oyster bar, or a cypress knee or mangrove root in the
                        > Everglades, or by a rock or log in the Suwanee. The weight concern is
                        > why I've been mostly looking at ply instant-type boats in the 125 to
                        > 150 pound range and wondering if that weight could be cut in half with
                        > composite construction. There are intriguing hints. For example, my 25-
                        > 30 pound solid wood mast on the Rolic2 could be replaced by a carbon
                        > fiber spar that would weight less than 10 pounds. In Pete Goss' book
                        > about single handed racing around the world, he mentions that the bare
                        > hull of his 50 footer could be turned over by 6 husky guys --- about
                        > what the 1/2 inch ply/fiberglass bare hull weighs on our 30-footer
                        > (which is a Gypsy-type hull).
                        >
                        > BTW Graeme, thanks for the suggestion of the Zephyr, but I ruled that
                        > out because while it is an excellent daysailer and can handle some
                        > nasty weather, it doesn't row very well, possibly because the 16-inch
                        > sides are too high. (I had one for many years, and was very fond of it.)
                        >
                        > Gary Blankenship
                        >
                        >
                        >
                        >
                        > Bolger rules!!!
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                      • Gary Lepak
                        Gary, For what it s worth, I once built a Bolger Dolphin, (Small Boats, Design #259, 18 x 4 ) out of 3/8 Airex foam with two layers of 6 oz glass inside and
                        Message 11 of 20 , Jul 3, 2005
                          Gary,

                          For what it's worth, I once built a Bolger Dolphin, (Small Boats, Design
                          #259, 18' x 4') out of 3/8" Airex foam with two layers of 6 oz glass inside
                          and out. It was a stripped down rowboat version, no centerboard, rudder or
                          rig. It weighed about a 100 lbs. I never weighed it, but two people could
                          throw it over their heads like a canoe. It seemed quite tough, and I never
                          worried about punctures or breakage. Of course it is a compound curved
                          hull so the bulding took some time with lofting and moldmaking, but you
                          would get a strong light hull this way. These days I would use Corefoam,
                          though it is expensive.

                          For a cheaper light boat that would be quicker to build I might try
                          lapstrake plywood. You could vary the plank thickness, say 4 to 5 mm on the
                          bottom and 3mm topsides.

                          Gary Lepak
                          Port Angeles, WA
                        • Howard Stephenson
                          To see a boat that is suitable for South Georgia, go to: http://www.ibiblio.org/ebooks/Shackleton/South/057.jpg Howard ;-]
                          Message 12 of 20 , Jul 3, 2005
                            To see a boat that is suitable for South Georgia, go to:

                            http://www.ibiblio.org/ebooks/Shackleton/South/057.jpg

                            Howard ;-]

                            --- In bolger@yahoogroups.com, "gbship" <gbship@c...> wrote:

                            > so at one point, competitors have to go up the St. Mary's
                            > river (in S. Georgia) and then portage their boats 40 MILES
                          • graeme19121984
                            Perhaps *the* small boat team time trial endurance event.
                            Message 13 of 20 , Jul 3, 2005
                              Perhaps *the* small boat team time trial endurance event.

                              --- In bolger@yahoogroups.com, "Howard Stephenson" <stephensonhw@a...>
                              wrote:
                              > To see a boat that is suitable for South Georgia, go to:
                              >
                              > http://www.ibiblio.org/ebooks/Shackleton/South/057.jpg
                              >
                              > Howard ;-]
                              >
                              > --- In bolger@yahoogroups.com, "gbship" <gbship@c...> wrote:
                              >
                              > > so at one point, competitors have to go up the St. Mary's
                              > > river (in S. Georgia) and then portage their boats 40 MILES
                            • James Greene
                              Wow, when I was thinking abut glass over foam construction I was considering 1 inch foam or thicker for the hulls. You guys are using foam that s less than
                              Message 14 of 20 , Jul 3, 2005
                                Wow, when I was thinking abut glass over foam construction I was
                                considering 1 inch foam or thicker for the hulls. You guys are using
                                foam that's less than half this thickness! Interesting ...

                                James Greene


                                On Jul 3, 2005, at 09:58, gbship wrote:

                                > A friend
                                > laminated a couple layers of glass on either side of 3/8 inch foam (I
                                > think that was the thickness) and you could whack it with a hammer
                                > without damage and it was considerably lighter than a ply sandwich
                                > would have been. I made some hatches for our Frolic2 of glass over 1/4-
                                > inch foam and those are reasonably strong, and very light, but not
                                > strong enough for use for a hull.
                              • James Greene
                                ... I wonder if the cheapest available foam might not be good enough for most small boats, provided it fills the void between the inner and outer skins and
                                Message 15 of 20 , Jul 3, 2005
                                  > These days I would use Corefoam,
                                  > though it is expensive.

                                  I wonder if the cheapest available foam might not be "good enough" for
                                  most small boats, provided it fills the void between the inner and
                                  outer skins and does not separate from them. Does this leave out good
                                  old fashioned styrofoam I wonder?

                                  James Greene
                                • Clyde Wisner
                                  I think I used inch and a half foam for my Brick and had to use a lot of glass and epoxy to get strength to stand in. I also made a deck of sorts from 1/4 ply
                                  Message 16 of 20 , Jul 4, 2005
                                    I think I used inch and a half foam for my Brick and had to use a lot of
                                    glass and epoxy to get strength to stand in. I also made a deck of sorts
                                    from 1/4 ply so the sides wouldn't bolge out. Overall, not worth the
                                    money in glass and epoxy, and the trouble. If you do go forward, I would
                                    think a multi
                                    chine rather than large flat areas like the bottom of a Brick. My foam
                                    Brick floats upside down of course and almost floated away during
                                    Isabell, which might not have been bad. Clyde.


                                    James Greene wrote:

                                    > > These days I would use Corefoam,
                                    > > though it is expensive.
                                    >
                                    > I wonder if the cheapest available foam might not be "good enough" for
                                    > most small boats, provided it fills the void between the inner and
                                    > outer skins and does not separate from them. Does this leave out good
                                    > old fashioned styrofoam I wonder?
                                    >
                                    > James Greene
                                    >
                                    >
                                    >
                                    >
                                    >
                                    >
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                                    [Non-text portions of this message have been removed]
                                  • Chris Stewart
                                    ... the ... at ... side. Consider skin on frame constuction using 26 ounce double ply woven nylon skin. Quoting from UMIAK An Illustrated Guide by Skip
                                    Message 17 of 20 , Jul 4, 2005
                                      --- In bolger@yahoogroups.com, Chris Lasdauskas <cml@t...> wrote:
                                      > 'To demonstrate his point, the builder took a hammer and wacked at
                                      the
                                      > sample panel mightily. With the hammer bouncing off harmlessly, he
                                      > offered it confidently to the skeptical architect. Taking the hammer,
                                      > the architect turned it claw-side down and -— with virtually no force
                                      at
                                      > all -— drove it right through Kevlar, the foam, and out the other
                                      side.


                                      Consider skin on frame constuction using 26 ounce double ply woven
                                      nylon skin. Quoting from "UMIAK An Illustrated Guide" by Skip Snaith:
                                      "The 26-ounce double-weave nylon skin on Tim's boat was incredibly
                                      tough; you could hit it with the claw end of a hammer as hard as you
                                      liked, and the hammer would bounce back."

                                      Skin on frame can produce very light boats. Platt Monfort's Geodesic
                                      Aerolight boats are incredibly light, but probably not strong enough
                                      for the Watertribe Challenge. Up the scantlings a bit, with the frame
                                      lashed rather than glued to preserve flexibility, and use a much
                                      tougher skin and you'd end up with a light, resilient boat.

                                      Chris Stewart
                                    • Gary Lepak
                                      James, The boatbuilding foams like Airex, Corecell and Divinicell are more dense than styrofoam. 5 to 8 lbs per cubic ft. compared to 1.1 (white) to 2 (pink
                                      Message 18 of 20 , Jul 4, 2005
                                        James,
                                        The boatbuilding foams like Airex, Corecell and Divinicell are more dense
                                        than styrofoam. 5 to 8 lbs per cubic ft. compared to 1.1 (white) to 2
                                        (pink or blue). The lighter the foam the thicker the skin needs to be to
                                        maintain the bond when struck. I've built two boats from blue foam, a tri
                                        that didn't last very long made of 1" thick foam with glass/epoxy skins,
                                        and a solid foam paddleboard I still have. The board has two layers of 6
                                        oz glass in epoxy resin on the bottom and a 3mm ply deck. The two layers of
                                        6 are about minimum I think, and it is still easily punctured or dented. It
                                        just doesn't matter much if it is, as it still floats, being solid foam. If
                                        you are always building boats with epoxy anyway, you fill the dings easily.
                                        The ply deck seems to take a lot of abuse without delaminating though, and
                                        could make a good boat with 1" foam inside 3mm ply with glass inside, but
                                        would probably weigh as much as 1/4" ply. I like using the blue foam though
                                        and still use it for things like outrigger floats or sponsons, i.e. solid
                                        foam objects with glass skin, rather than as a foam sandwich hull skin .
                                        Gary Lepak


                                        ----- Original Message ----- > I wonder if the cheapest available foam might
                                        not be "good enough" for
                                        > most small boats, provided it fills the void between the inner and
                                        > outer skins and does not separate from them. Does this leave out good
                                        > old fashioned styrofoam I wonder?
                                        >
                                        > James Greene
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