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Re: [bolger] Re: Sinkers v. Swimmers

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  • frboblynn@aol.com
    In a message dated 2/1/04 10:00:42 PM, jboatguy@cs.com writes:
    Message 1 of 23 , Feb 1, 2004
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      In a message dated 2/1/04 10:00:42 PM, jboatguy@... writes:

      << the day

      will come when a blue-water sailboat bum can ask a sailboat dealer if

      the dreamboat he or she is eyeing has positive flotation, and not be

      laughed out the door... >>

      OK, I don't understand this. While the discussion of ballast and flotation
      has been interesting, it really has been pretty impossible to be sure of
      anything except that things change. Now maybe someone can tell me something I need
      to know in addition to this truism. I have built a beautiful little dory I
      came across in the SBJ. It is not completely finished as I have not been able
      to bring myself to putting a hole in the bottom for a daggerboard and make
      other modification for a mast. It is said to be a "9 foot dory" but it is really
      6' along the bottom, and I believe that makes it a 6 foot dory. It has a tank
      at the stern and another at the bow. I filled both with Styrofoam thinking
      that I would be improving its safety. I never built a boat before. The bottom
      has been glassed--needs more sanding--and I thought I would glass the sides.
      It holds water. I know that because it was in the basement when my house
      burned and
      water from the fire department's hoses flooded it. But it has never been in
      the water. I am wondering if my putting Styrofoam fore and aft was a good
      idea or a bad
      one; it's all glassed in either way as I sealed these spaces with
      fiberglass. Any advice about this? I'd appreciate knowing if I should go on with the
      project or if my
      little addition of "positive flotation" will be a problem of some sort? I
      hope this is
      all clear.

      Thanks and best wishes to all,
      boblynn
      frboblynn@...
    • fountainb@switch.aust.com
      ... If your fore and aft spaces are completely sealed then the foam is perhaps redundant, but it can t do any harm. It also ensures that the spaces remain
      Message 2 of 23 , Feb 1, 2004
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        frboblynn wrote:
        > I am wondering if my putting Styrofoam fore and aft was a good
        > idea or a bad one; it's all glassed in either way as I sealed
        > these spaces with fiberglass

        If your fore and aft spaces are completely sealed then the foam
        is perhaps redundant, but it can't do any harm. It also ensures
        that the spaces remain bouyant even if the hull is breached.
        Personally I don't like completely sealed spaces - expanding
        air can blow the joints as the boat heats up in the sun. And
        if there is even a hairline crack it will suck water as the
        boat flexes. I prefer to install inspection hatches, and I
        usually use removably bouyancy (aka plastic milk bottles)
        rather than foam to make it easier to access the space for
        repairs. But that is just my personal preference.

        The ballast/floatation discussions don't really apply to
        your dory, since the only ballast in your dory is your
        good self.

        Don't stress over cutting a hole for the daggerboard.
        I know exactly how you feel, but it is really a very
        straighforward exercise. Make your centreboard case a
        little oversize, so that it pokes through the bottom.
        After glueing it in place from the inside, flip and trim
        the case down to the hull. Saves fiddling about working
        out the angle of the hull.

        Good to hear that the boat survived the fire. Maybe you
        should call her "Phoenix" :-)


        Bruce Fountain
        Senior Software Engineer
        Union Switch & Signal
        Perth, Western Australia
      • frboblynn@aol.com
        Thanks, Bruce, for sharing your opinion and for your encouragement. Phoenix would be a great name for this boat. I hadn t planned to name it. But I hadn t
        Message 3 of 23 , Feb 1, 2004
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          Thanks, Bruce, for sharing your opinion and for your encouragement. Phoenix
          would be
          a great name for this boat. I hadn't planned to name it. But I hadn't
          planned not to name it either. Just haven't thought about it. But great idea, and
          I thank you for the
          suggestion. Also, there would have been another tank at the thwart but I
          decided I
          need passage ways for water to run back to the back so I could bail it out.
          I feel sure
          if I sailed it, it will take on water through the centerboard case and
          possibly over the sides at times when wave action is high. I plan to put plastic
          bottles in that area.

          Thanks again. Hope you are sailing. It has been below zero here lately (was
          warmer
          today but still way too cold to put a boat in the water.

          Fair winds,
          boblynn
          frboblynn@...
          Just outside Chicago in Park Forest, IL, USA
        • grant corson
          on 2/2/04 1:04 AM, frboblynn@aol.com at frboblynn@aol.com wrote: What you have done is made your boat more seaworthy by adding the styrofoam, hopefully of the
          Message 4 of 23 , Feb 2, 2004
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            on 2/2/04 1:04 AM, frboblynn@... at frboblynn@... wrote:
            What you have done is made your boat more seaworthy by adding the styrofoam,
            hopefully of the closed cell variety. You could have achieved the same
            effect or better by sealing the "tanks" and having simply dead air in them
            with a drain plug should they develop a leak over time, rock on!!!
            Grant

            I am wondering if my putting Styrofoam fore and aft was a good
            > idea or a bad
            > one; it's all glassed in either way as I sealed these spaces with
            > fiberglass. Any advice about this? I'd appreciate knowing if I should go on
            > with the
            > project or if my
            > little addition of "positive flotation" will be a problem of some sort? I
            > hope this is
            > all clear.
            >
            > Thanks and best wishes to all,
            > boblynn
            > frboblynn@...
            >
            > Bolger rules!!!
            > - no cursing, flaming, trolling, spamming, 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
            >
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            >
          • Nels
            ... Design ... Hi John, Are you sure the figures you are using above are correct? The reason I ask is that 74 cubic feet of water is a pretty large tank. For
            Message 5 of 23 , Feb 2, 2004
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              --- In bolger@yahoogroups.com, "oneillparker" <jboatguy@c...> wrote:
              > Continuing from my last post (34128), I worked out the numbers for
              > St. Valery, (25' overall) based on the drawings of her in Boat
              Design
              > Quarterly (#10) as for water vs. lead ballast.
              >
              > Bolger shows 2.1 m3 (74.2 ft3) of water ballast, about 4700 pounds,
              > stuck in the bilge. From what I can tell it seems to be distributed
              > outboard port and starboard, mostly under dressers and berths, and
              > doesn't seem to impact centerline headroom at all.
              >
              Hi John,

              Are you sure the figures you are using above are correct? The reason
              I ask is that 74 cubic feet of water is a pretty large tank. For
              example if the tank was 15 feet long by 5 feet wide by 1 foot high it
              would contain 75 cubic feet, and would indeed hold 4700 pounds of
              water if your weight per cubic figure is correct. That is almost 21/2
              tons of water to pump in and out of the boat every time you want to
              go sailing. How is this accomplished I am wondering?

              I really admire the looks of the design, but feel there must be a
              glitch in the ballest figures somewhere. 470 pounds on each side
              would make more sense to me, as you would need more because I don't
              think you would have the same righting leverage as lead installed in
              a salient keel like LONG MICRO. (With 520 pounds)

              I would consider locating the closed cell foam as insulation in
              between the roof beams and upper hull sides above the dressers. This
              would add comfort, (preventing condensation) as well as safety.

              Nels
            • oneillparker
              Nels, I think you re right, and I m wrong. St. Valery is drawn to metric measurements. The profile view in BDQ shows C.B. next to a bulls- eye type symbol
              Message 6 of 23 , Feb 2, 2004
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                Nels,

                I think you're right, and I'm wrong. St. Valery is drawn to metric
                measurements. The profile view in BDQ shows "C.B." next to a bulls-
                eye type symbol then "2.1 m3," then below it "(c.4700 LBS.)" All
                those numbers and symbols are within the confines of the water
                ballast tanks, which led to my quick assumption that he was referring
                to the ballast.

                But you're right, that assumption makes no sense; it's too big. Taken
                with the fact that there are other numbers showing 4700lbs
                displacement(how did I not notice that!) it's clear 4700 is total.

                The article also shows 1000 lbs trailer weight (which seems low to
                me...) That's a min. 3700 lbs ballast, but a lot of that (1700 lbs?)
                is probably assumed to be folks and gear. Maybe 2000 lbs ballast?

                That's more reasonable. 31+ ft3 of tanks. The tanks shown extend
                about 7' fore and aft.

                Thank for pointing it out...

                By the way, the drawings show a flotation fore and aft in the wells.

                John O'Neill



                --- In bolger@yahoogroups.com, "Nels" <arvent@h...> wrote:
                > Are you sure the figures you are using above are correct? The
                reason
                > I ask is that 74 cubic feet of water is a pretty large tank. For
                > example if the tank was 15 feet long by 5 feet wide by 1 foot high
                it
                > would contain 75 cubic feet, and would indeed hold 4700 pounds of
                > water if your weight per cubic figure is correct. That is almost
                21/2
                > tons of water to pump in and out of the boat every time you want to
                > go sailing. How is this accomplished I am wondering?
                >
                > I really admire the looks of the design, but feel there must be a
                > glitch in the ballest figures somewhere. 470 pounds on each side
                > would make more sense to me, as you would need more because I don't
                > think you would have the same righting leverage as lead installed
                in
                > a salient keel like LONG MICRO. (With 520 pounds)
                >
                > I would consider locating the closed cell foam as insulation in
                > between the roof beams and upper hull sides above the dressers.
                This
                > would add comfort, (preventing condensation) as well as safety.
                >
                > Nels
              • pvanderwaart
                By comparison, the Jochems schooner is about the same size and the displacement is given as 5000lbs. I don t know about the amount of water. As the thead on
                Message 7 of 23 , Feb 2, 2004
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                  By comparison, the Jochems schooner is about the same size and the
                  displacement is given as 5000lbs. I don't know about the amount of
                  water.

                  As the thead on water ballast has amply demonstrated, it's not an
                  easy topic to understand. The bottom line, however, is that water
                  ballast works best in a fairly light boat with a flat or nearly flat
                  bottom. St. Valery, Jochems and Martha Jane are all examples, and
                  together sugggest that PCB would agree. In addition, due to it's
                  bulk, it works best with a ballast/displacement ratio that is low to
                  moderate, say about 25% tops. With metal ballast, a hull like this
                  might go as high as 50%, e.g. the LFH Meadowlark.

                  Peter
                • frboblynn@aol.com
                  Thanks for your response, Grant. By rock on I hope you don t mean that I am going to be rocking up and down in my little dory. I am interested in your
                  Message 8 of 23 , Feb 2, 2004
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                    Thanks for your response, Grant. By "rock on" I hope you don't mean that I
                    am going to be "rocking" up and down in my little dory. I am interested in
                    your idea about a drain
                    plug for my fore and aft tanks. In part, my interest comes from a concerned
                    expressed by Bruce Fountain about the tanks developing cracks that leaks due
                    to sun
                    and their being sealed. So good idea. Thanks.
                    best wishes,
                    boblynn
                    frboblynn@...
                    living just outside Chicago
                  • Nels
                    ... mean that I ... interested in ... I have owned about 15 diferent canoes over the years and almost all of them had sealed floatation tanks at both ends.
                    Message 9 of 23 , Feb 2, 2004
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                      --- In bolger@yahoogroups.com, frboblynn@a... wrote:
                      > Thanks for your response, Grant. By "rock on" I hope you don't
                      mean that I
                      > am going to be "rocking" up and down in my little dory. I am
                      interested in
                      > your idea about a drain
                      > plug for my fore and aft tanks.

                      I have owned about 15 diferent canoes over the years and almost all
                      of them had sealed floatation tanks at both ends. Never had one crack
                      and that includes dumping in rapids many times.

                      They have been left outside in tmeperatures ranging from 40 below to
                      100 above. Closed cell foam doesn's seem to change too much but the
                      inserts are just snug and not expanded foam.

                      Cheers, Nels
                    • frboblynn@aol.com
                      Well, thanks, Nels. Thanks good to know. I was attracted to this dory because it could be constructed inexpensively, quickly, and when finished weighs 45
                      Message 10 of 23 , Feb 2, 2004
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                        Well, thanks, Nels. Thanks good to know. I was attracted to this dory
                        because it could be constructed inexpensively, quickly, and when finished weighs 45
                        lbs. (which
                        was particularly attractive as I needed to carry it over a dune to get to the
                        beach),
                        and because its is such a beautiful boat. I need to get busy and finish it.
                        Maybe this
                        spring will be the year.

                        Best wishes,
                        boblynn
                        frboblynn@...
                        just outside Chicago
                      • fountainb@switch.aust.com
                        ... I used to sail a laser, and that would suck water through the tiniest holes (usually the join between the hull and deck) as the hull flexed. Mind you, the
                        Message 11 of 23 , Feb 2, 2004
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                          Nels wrote:
                          > I have owned about 15 diferent canoes over the years and almost all
                          > of them had sealed floatation tanks at both ends. Never had one crack
                          > and that includes dumping in rapids many times.

                          I used to sail a laser, and that would suck water through the
                          tiniest holes (usually the join between the hull and deck) as
                          the hull flexed. Mind you, the enclosed space on a laser is
                          very large (the entire 14ft hull) and subject to continuous
                          stress.

                          I tend to be pessimistic about these things - any enclosed
                          space will eventually leak, and you will wish you had installed
                          an access port.

                          > They have been left outside in tmeperatures ranging from 40 below to
                          > 100 above. Closed cell foam doesn's seem to change too much but the
                          > inserts are just snug and not expanded foam.

                          Oh, 100F. I was talking about HOT weather :-)

                          I think that your spaces must have leaked to some extent, or your
                          canoe would have looked like a blimp on a hot day. Or maybe the
                          walls were very rigid.

                          Bruce Fountain
                          Senior Software Engineer
                          Union Switch & Signal
                          Perth, Western Australia
                        • Nels
                          ... Can t blame you for being pessimistic based on your experience. I know of only one canoe that leaked water into a floatation compartment and that was an
                          Message 12 of 23 , Feb 2, 2004
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                            --- In bolger@yahoogroups.com, fountainb@s... wrote:
                            > I tend to be pessimistic about these things - any enclosed
                            > space will eventually leak, and you will wish you had installed
                            > an access port.
                            >
                            > I think that your spaces must have leaked to some extent, or your
                            > canoe would have looked like a blimp on a hot day. Or maybe the
                            > walls were very rigid.

                            Can't blame you for being pessimistic based on your experience.

                            I know of only one canoe that leaked water into a floatation
                            compartment and that was an aluminum model, owned by a friend. You
                            would soon know once you start on a long portage if one leaked as the
                            weight of the water in either end would soon become intolerable.
                            (Which is what happened to the aluminum one.)

                            One could easily test a block of foam for expansion by measuring it
                            and then putting it into an over at whatever temperature you consider
                            to be hot. My guess is the air expands inside and compresses the cell
                            walls around it and the outer volume hardly changes. This of course
                            would not be the case with a plastic bottle or something that doesn't
                            enclose the air in small compressable chambers. An empty tank would
                            build up more pressure than one filled with foam I would think. So
                            therefore an empty chamber should have a relief valve of some kind
                            perhaps. I don't consider an empty sealed chamber to be that safe
                            myself. Better than nothing perhaps.

                            Nels
                          • dbaldnz
                            I beg to disagree Bruce. I raced a laser for 3 years, and it never wracked or leaked. Your one must have been a real dunger! Also I built an Elegant Punt. I
                            Message 13 of 23 , Feb 3, 2004
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                              I beg to disagree Bruce.
                              I raced a laser for 3 years, and it never wracked or leaked. Your one
                              must have been a real dunger!
                              Also I built an Elegant Punt. I glued ply sides to the full length
                              thwart, down to the bottom to form a permanent air chamber. Until it
                              was stolen after 8 years, always outside uncovered, it never leaked
                              or showed any signs of unwanted activity.
                              Providing the inner space is epoxy sealed, and joins are taped, there
                              need be no problem.
                              DonB

                              > I used to sail a laser, and that would suck water through the
                              > tiniest holes (usually the join between the hull and deck) as
                              > the hull flexed. Mind you, the enclosed space on a laser is
                              > very large (the entire 14ft hull) and subject to continuous
                              > stress.
                              >
                              > I tend to be pessimistic about these things - any enclosed
                              > space will eventually leak, and you will wish you had installed
                              > an access port.
                              > Bruce Fountain
                              > Senior Software Engineer
                              > Union Switch & Signal
                              > Perth, Western Australia
                            • Roger Derby
                              I guess the Laser must not have the vent built into the Sunfish? On the Sunfish, high up on the forward side of the footwell, hidden under the deck overhang,
                              Message 14 of 23 , Feb 3, 2004
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                                I guess the Laser must not have the vent built into the Sunfish? On the
                                Sunfish, high up on the forward side of the footwell, hidden under the deck
                                overhang, is a small hole, smaller than 1/8" which serves to prevent
                                "pumping." One has to really look to find it.

                                It didn't prevent the leaks which resulted from:
                                1) slamming the (old style) rudder down with leeway on so that it missed
                                the catch and poked a hole in the transom, and
                                2) running full speed into a gravel beach with the dagger board all the way
                                down (then's when it got the bumper someone else mentioned earlier).

                                Roger
                                derbyrm at starband.net
                                http://derbyrm.mystarband.net

                                ----- Original Message -----
                                From: "dbaldnz" <oink@...>
                                To: <bolger@yahoogroups.com>
                                Sent: Tuesday, February 03, 2004 2:22 PM
                                Subject: [bolger] Re: Sinkers v. Swimmers


                                > I beg to disagree Bruce.
                                > I raced a laser for 3 years, and it never wracked or leaked. Your one
                                > must have been a real dunger!
                                > Also I built an Elegant Punt. I glued ply sides to the full length
                                > thwart, down to the bottom to form a permanent air chamber. Until it
                                > was stolen after 8 years, always outside uncovered, it never leaked
                                > or showed any signs of unwanted activity.
                                > Providing the inner space is epoxy sealed, and joins are taped, there
                                > need be no problem.
                                > DonB
                                >
                                > > I used to sail a laser, and that would suck water through the
                                > > tiniest holes (usually the join between the hull and deck) as
                                > > the hull flexed. Mind you, the enclosed space on a laser is
                                > > very large (the entire 14ft hull) and subject to continuous
                                > > stress.
                                > >
                                > > I tend to be pessimistic about these things - any enclosed
                                > > space will eventually leak, and you will wish you had installed
                                > > an access port.
                                > > Bruce Fountain
                                > > Senior Software Engineer
                                > > Union Switch & Signal
                                > > Perth, Western Australia
                                >
                                >
                                > Bolger rules!!!
                                > - no cursing, flaming, trolling, spamming, 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
                                >
                                > To visit your group on the web, go to:
                                > http://groups.yahoo.com/group/bolger/
                                >
                                > To unsubscribe from this group, send an email to:
                                > bolger-unsubscribe@yahoogroups.com
                                >
                                > Your use of Yahoo! Groups is subject to:
                                > http://docs.yahoo.com/info/terms/
                                >
                                >
                              • fountainb@switch.aust.com
                                ... Small leaks at the hull/deck join are pretty common on older lasers (mine was around 37400 or so). I saw the same thing on a couple of other hulls at my
                                Message 15 of 23 , Feb 3, 2004
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                                  dbaldnz wrote:
                                  > I raced a laser for 3 years, and it never wracked or leaked. Your one
                                  > must have been a real dunger!

                                  Small leaks at the hull/deck join are pretty common on
                                  older lasers (mine was around 37400 or so). I saw the same
                                  thing on a couple of other hulls at my club. I fixed it by
                                  gouging out a channel in the join with a blade and filling
                                  with epoxy. Plus, of course, all the other opportunities for
                                  damage around the dagger board, mast step, pintles etc.
                                  Lasers are sailed pretty hard and the flexing of the hull
                                  will suck a surprising amount of water through a very small
                                  hole.

                                  Bruce Fountain
                                  Senior Software Engineer
                                  Union Switch & Signal
                                  Perth, Western Australia
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