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[bolger] MJ Musings

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  • John Gerty
    Can we handle one more message w/o sinking? Here s Zephyr s contribution: New to the group, so who is he? Since October 1993, proud and happy owner/skipper of
    Message 1 of 11 , Mar 11, 2000
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      Can we handle one more message w/o sinking? Here's Zephyr's
      contribution:

      New to the group, so who is he? Since October 1993, proud and happy
      owner/skipper of Zephyr, the first Martha Jane (and the one in the
      BwaOM picture on page 259 despite the caption), built by Richard
      Cullison who launched her in June 1990. Richard took Zephyr up to
      Gloucester that summer, and Mr. Bolger sailed her. Maybe I'm the oldest
      codger in the group with less sailing experience than most of you, but
      I have enjoyed my MJ for nearly seven years. I have found her stable,
      fast and forgiving of even my worst mistakes. Also Steve and I have had
      voluminous e-mail correspondence starting even before he purchased his
      plans (Steve, do you hold me responsible?) and continuing throughout
      the building of Landroval. With that background, may I be allowed to
      add my two cents to the pot? My only previous contribution was no. 3497
      Mar. 7 suggesting a possible scenario for Steve's situation leading to
      capsize.

      I started this before seeing the most recent batch of messages, but I
      can now add "well said Donald" to his "Well said Bennett" in their
      postings of 10 Mar. Like Bennett, Cullison also built Zephyr `to
      plan' with the same exception of 3/8" ply for the cabin top. One does a
      lot of walking over that top. And like Donald, I cautioned Steve about
      modifications and about the effect of his 200 pounds further aft in
      that tempting extra space. I don't know how that might affect handling,
      but I have found Zephyr can be made to go a bit faster when I move
      further forward in the cockpit, and being `tail heavy' might make it
      more difficult to head up in marginal conditions. Try turning a canoe
      to windward while paddling from the stern as an extreme example.

      The only times Zephyr has approached knockdown were when I made
      mistakes like an accidentally cleated sheet in strong, gusty conditions
      on Lake Champlain and a poorly controlled jibe on the Chester River
      severe enough to catapult me overboard and snap the downhaul which of
      course had a weak link I had neglected to fix. That time we were headed
      down wind with mizzen furled, wind at least 20, being forced toward a
      lee shore and unable to tack around without the mizzen. Fortunately we
      had the anchor in the cockpit, so my wife could stop the boat and I
      could get back aboard to deal with 200 (less reefs) square feet of kite
      (mainsail/boom/yard) tethered only by sheet and halyard, and flailing
      madly about trying to destroy everything within reach including me. One
      of the mizzen ties had also slipped down releasing a balloon of sail
      slatting in the wind violently enough to shear off the mizzen mast
      step. Throughout all this mistreatment Zephyr never heeled far enough
      to ship any water, and only I got wet. She dutifully held to her anchor
      (and probably snickered) while I straightened out the mess. From my
      experiences I cannnot agree with `Pippo's, "---MJ is an inherently
      tender design." or, forgive me Steve, your comment, "----needs little -
      a mizzen is enough - to knock her over." Are all MJs created equal?

      Perhaps it is time to sort and assess the mountain of messages produced
      so far, and I too am glad Mr. Bolger has returned -his `ruminating'
      usually produces excellent results. For what they ar3e worth, here are
      some questions and comments that come to my mind:

      1. How many Martha Janes have been built and sailed, how many have
      really suffered ninety degree knockdownI (is it really 6 of 7?), and
      under what conditons did they occur?

      2. Which were built strictly to plan and which have design or
      construction differences which could contribute to easier knockdown?
      For instance, at least one seems to have a heavy mast, and Steve has
      said he built Landroval to be bullet proof (is that the correct word,
      Steve?) to survive the Florida climate. If memory serves me all his
      plywood panels have fiberglass/epoxy skins on both surfaces. Would that
      add significant topside weight to require more ballast?

      3. All the discussions of ballast material and location boil down to
      `500 pounds is 500 pounds' as long as it is in the designated space and
      cannot shift. And that sealed space is what determines that part of
      total buoyancy not the material within. That is why I first suggested
      to Steve that he might consider sand bags at least as a simple
      temporary way of providing ballast if he wanted to avoid wet tanks and
      thru hull openings and was willing to tote the extra trailer weight. (I
      suggested 25 ten pound bags tightly packed in each tank.) Unless I'm
      mistaken the important thing about ballast is its contribution to the
      location of the center of gravity (c.g.) of the whole vessel. Stability
      or righting moment at any attitude of roll is determined by where the
      c.g. is with respect to the center of buoyancy (c.b.) which in turn
      depends on the geometry of whatever part of the boat is in the water
      (preferably the hull!) and changes location with attitude as in
      heeling. The c.g. also can change position with any change in weight or
      location of crew, equipment, etc. In other words you cannot get the
      whole picture considering only ballast.

      I strongly recommend all of you Bolgeristas get "WoodenBoat" magazine
      Number 114, September/October 1993, and read Mike O'Brien's article
      `Shoal-Draft Sharpies' - Simple, self-righting, and roomy, starting
      on page 64. Mike is a recognized authority on these subjects, and his
      article gives loads of information on various sharpie design concepts,
      components and performnce including several Bolger boats. There is more
      good stuff on stability including "Surprising Stability Curves" of
      Bruce Kirby's 31' Norwalk Islands Sharpie calculated by AeroHydro, Inc.
      It is an excellent graphic explanation of c.g./ c.b. interaction. Look
      carefully and you will even find mention of Martha Jane. Turn the page
      and you will find PCB's article "A New (?) Tack for a Dipping Lug".
      This issue is a short course education for all Bolger devotees. Enjoy!

      If this is too long, at least it's free - and worth every penny. --John
      Gerty
    • Hwal@aol.com
      Hi John - I am smiling down here !:-) Grinning actually - as I read about how stiff zephyr is because I remember how much you told me she weights! According to
      Message 2 of 11 , Mar 12, 2000
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        Hi John - I am smiling down here !:-) Grinning actually - as I read about how
        stiff zephyr is because I remember how much you told me she weights!
        According to the number you gave me a couple months ago I figure that you
        have at least three times the ballast that I have! Of course it comes in the
        form of batteries, electronics, extra gasoline, drinkable water, canned
        goods, books, a 9.9 honda, paddles, head, whatever is in the head, galley,
        maps, anchors, line, camera, clothing, lights ( you don't have an inflatable
        dingy in there do you?) . John! You could shinny up to the top of the mast in
        a gale and not wobble one centimeter - which also explains how you could even
        fly a tops'l above your main! Landroval on the other hand has a piddly 500 (
        600 now - I added another hundred) pounds of sand and whatever the cooler
        weights after lunch is gone! And my little honda only weights 25 lbs and
        doesn't even have an eternal gas can :-(

        And of course - should you ever need a sea anchor - you have plenty to choose
        from
        - in my case I would have to choose between my sand bags and my wife. But we
        won't go there :-0

        Happy cruising. You have a class a1 cruising vessel.

        Incidentally - I just heard recently that the nis23 normally carries 700 lbs
        of ballast but that the racers ( those who aren't loaded up with cruising
        stuff ) normally add 300 more pounds. That's a 1000 lbs. of ballast. Wow -.

        steve
      • Giuseppe 'Pippo' Bianco
        John - Martha Jane s ballast/displacement ratio is 0.21, and I estimate by looking at the drawings in BWAOM that the center of gravity (center of mass would be
        Message 3 of 11 , Mar 12, 2000
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          John - Martha Jane's ballast/displacement ratio is 0.21, and I estimate
          by looking at the drawings in BWAOM that the center of gravity (center
          of mass would be more proper, but less nautical) is at least 30 cm
          above the water level. Well, you may not agree, but I consider this a
          tender boat. This of course is a relative term. My benchmarks are Micro
          and Long Micro. PCB himself speaks of "a good range of stability": he
          correctly never mentions self-righting, which ever boat is within its
          range of stability.
          Best, Pippo

          "john gerty" <gertyjand-@...> wrote:

          > experiences I cannnot agree with `Pippo's, "---MJ is an inherently
          > tender design." or, forgive me Steve, your comment, "----needs little
          -
          > a mizzen is enough - to knock her over." Are all MJs created equal?
        • John Gerty
          Pippo - Thanks for the semantics lesson, and I agree center of mass would be more proper , but back in my early engineering days, center of gravity was
          Message 4 of 11 , Mar 12, 2000
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            Pippo - Thanks for the semantics lesson, and I agree 'center of mass
            would be more proper', but back in my early engineering days, center of
            gravity was commonly used; I was not attempting nautical airs just
            reverting to old habits - old fart privilege. You are of course
            correct about the O.21 ballast/displacement ratio based on the 2350
            lb.nominal displacement. Did you read Steve's grinning (?) response to
            my message? He is close to the mark on how loaded down Zephyr tends to
            be. Add another 300 or so pounds of miscellaneous gear to the
            displacement, and you can calculate ratios of 0.19 or 0.30 depending on
            whether you add it just to displacement or to both displacement and
            ballast. Figures don't lie, but liars sure can figure?? At least some
            of the 'extras' are low enough to be ballast as long as they stay put!
            By your benchmarks you may now consider my MJ either more or less
            tender than designed. Your choice.

            I'm not sure what Zephyr's actual displacement is with or without
            impedimenta, but it is probably somewhere near that range. Based on how
            she sits in the water I would reduce your 30 cm to about 23 cm for what
            that is worth. Since you allow that 'tender' is a relative term, I can
            consider Zephyr not a tender boat based on how she has performed, and
            how forgiving she has been. From my experience so far I have no quarrel
            with Mike O'Brien's summary,"Built as drawn, MARTHA JANE should be
            self-bailing, self-righting, unsinkable, easily trailerable, and fast
            under sail. She's a most significant sharpie." Like Bennett I have no
            intentions of further testing self-righting, but she has lived up to
            all my other expectations. Meanwhile I'll live with PCB's "a good range
            of stability" and try to improve my skills.
            Best to you, too - John
          • John Gerty
            Hello Steve - Keep grinning. Your loading assessment is not too far off. My Honda is only 8 HP not 9.9 so shave off a couple lbs. Guess what - I DO have an
            Message 5 of 11 , Mar 12, 2000
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              Hello Steve - Keep grinning. Your loading assessment is not too far
              off. My Honda is only 8 HP not 9.9 so shave off a couple lbs. Guess
              what - I DO have an inflatable up there, but it only weighs 17 lb. bag
              and all, and can't count as ballast on house top. I agree, I have an a1
              cruising vessel, but isn't that what Martha Jane is all about? Her
              capabilities are wasted if the only use is day sailing which we seldom
              do being so far from launch sites. In fact only once did I take a
              couple of friends down to Buzzards Bay for the day. Far more drive,
              launch, retrieve, drive than sailing. When we go it's usually long
              distance and supplies for a week or two with usual overkill. 2 anchors,
              tools and all the plugger nicities. One of our SWS friends forgot his
              camp stove up on Lake Champlain, so I found a spare one burner job
              under the bunk for them. Be prepared! Can't complain though, cause she
              usually out performs her companions even loaded down and with me at the
              helm. - John
            • Giuseppe 'Pippo' Bianco
              Hi John ... I didn t intend to teach anything, I was just self-ruminating. Sorry if appeared like that. I use the term COG as well, as it s used in all boat
              Message 6 of 11 , Mar 13, 2000
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                Hi John

                "john gerty" <gertyjand-@...> wrote:

                > Pippo - Thanks for the semantics lesson

                I didn't intend to teach anything, I was just self-ruminating. Sorry if
                appeared like that. I use the term COG as well, as it's used in all
                boat design books. Luckily enough, the gravity field around a boat is
                sufficiently constant to make the two points coincide within microns, I
                guess! ;-)

                > with Mike O'Brien's summary,"Built as drawn, MARTHA JANE should be
                > self-bailing, self-righting, unsinkable, easily trailerable, and fast
                > under sail. She's a most significant sharpie."

                I think that MJ is a very clever design, and I like it except for the
                name and the leeboards, buth this is just a personal bias.

                Best, Pippo
              • Hwal@aol.com
                John - not only is zephyr a class a1 cruiser - so are you! A dingy and an extra stove. I love it! Steve ( I m grinning)
                Message 7 of 11 , Mar 13, 2000
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                  John - not only is zephyr a class a1 cruiser - so are you! A dingy and an
                  extra stove. I love it! Steve ( I'm grinning)
                • Hwal@aol.com
                  In a message dated 3/13/2000 6:04:16 AM Eastern Standard Time, giuseppe.bianco@asi.it writes:
                  Message 8 of 11 , Mar 13, 2000
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                    In a message dated 3/13/2000 6:04:16 AM Eastern Standard Time,
                    giuseppe.bianco@... writes:

                    << I think that MJ is a very clever design, and I like it except for the
                    name and the leeboards, buth this is just a personal bias.

                    Best, Pippo >>

                    Pippo!!!! Who cares about self righting, self bailing and "most significant"?
                    It's the name and the leeboards that count! Steve
                  • c.ruzer
                    Enjoy that recommended educational reading from below:
                    Message 9 of 11 , Dec 29, 2013
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                      Enjoy that recommended educational reading from below:


                      http://groups.yahoo.com/neo/groups/bolger/files/Shoal%20Draft%20Sharpies%2C%20and%20Bolger%20on%20lugsail%20peak%20halyards/



                      ---In bolger@{{emailDomain}}, <gertyjandp@...> wrote:

                      Can we handle one more message w/o sinking? Here's Zephyr's
                      contribution:

                      New to the group, so who is he? Since October 1993, proud and happy
                      owner/skipper of Zephyr, the first Martha Jane (and the one in the
                      BwaOM picture on page 259 despite the caption), built by Richard
                      Cullison who launched her in June 1990. Richard took Zephyr up to
                      Gloucester that summer, and Mr. Bolger sailed her. Maybe I'm the oldest
                      codger in the group with less sailing experience than most of you, but
                      I have enjoyed my MJ for nearly seven years. I have found her stable,
                      fast and forgiving of even my worst mistakes....

                      I strongly recommend all of you Bolgeristas get "WoodenBoat" magazine
                      Number 114, September/October 1993, and read Mike O'Brien's article
                      `Shoal-Draft Sharpies' - Simple, self-righting, and roomy, starting
                      on page 64. Mike is a recognized authority on these subjects, and his
                      article gives loads of information on various sharpie design concepts,
                      components and performnce including several Bolger boats. There is more
                      good stuff on stability including "Surprising Stability Curves" of
                      Bruce Kirby's 31' Norwalk Islands Sharpie calculated by AeroHydro, Inc.
                      It is an excellent graphic explanation of c.g./ c.b. interaction. Look
                      carefully and you will even find mention of Martha Jane. Turn the page
                      and you will find PCB's article "A New (?) Tack for a Dipping Lug".
                      This issue is a short course education for all Bolger devotees. Enjoy!


                    • c.ruzer
                      Enjoy that recommended educational reading from below:
                      Message 10 of 11 , Dec 29, 2013
                      • 0 Attachment


                        Enjoy that recommended educational reading from below:


                        http://groups.yahoo.com/neo/groups/bolger/files/Shoal%20Draft%20Sharpies%2C%20and%20Bolger%20on%20lugsail%20peak%20halyards/



                        ---In bolger <gertyjandp@...> wrote:

                        Can we handle one more message w/o sinking? Here's Zephyr's
                        contribution:

                        New to the group, so who is he? Since October 1993, proud and happy
                        owner/skipper of Zephyr, the first Martha Jane (and the one in the
                        BwaOM picture on page 259 despite the caption), built by Richard
                        Cullison who launched her in June 1990. Richard took Zephyr up to
                        Gloucester that summer, and Mr. Bolger sailed her. Maybe I'm the oldest
                        codger in the group with less sailing experience than most of you, but
                        I have enjoyed my MJ for nearly seven years. I have found her stable,
                        fast and forgiving of even my worst mistakes....

                        I strongly recommend all of you Bolgeristas get "WoodenBoat" magazine
                        Number 114, September/October 1993, and read Mike O'Brien's article
                        `Shoal-Draft Sharpies' - Simple, self-righting, and roomy, starting
                        on page 64. Mike is a recognized authority on these subjects, and his
                        article gives loads of information on various sharpie design concepts,
                        components and performnce including several Bolger boats. There is more
                        good stuff on stability including "Surprising Stability Curves" of
                        Bruce Kirby's 31' Norwalk Islands Sharpie calculated by AeroHydro, Inc.
                        It is an excellent graphic explanation of c.g./ c.b. interaction. Look
                        carefully and you will even find mention of Martha Jane. Turn the page
                        and you will find PCB's article "A New (?) Tack for a Dipping Lug".
                        This issue is a short course education for all Bolger devotees. Enjoy!

                      • c.ruzer
                        Enjoy that recommended educational reading from below:
                        Message 11 of 11 , Dec 29, 2013
                        • 0 Attachment

                          Enjoy that recommended educational reading from below:


                          http://groups.yahoo.com/neo/groups/bolger/files/Shoal%20Draft%20Sharpies%2C%20and%20Bolger%20on%20lugsail%20peak%20halyards/



                          ---In bolger@yahoogroups.com, <gertyjandp@...> wrote:

                          Can we handle one more message w/o sinking? Here's Zephyr's
                          contribution:

                          New to the group, so who is he? Since October 1993, proud and happy
                          owner/skipper of Zephyr, the first Martha Jane (and the one in the
                          BwaOM picture on page 259 despite the caption), built by Richard
                          Cullison who launched her in June 1990. Richard took Zephyr up to
                          Gloucester that summer, and Mr. Bolger sailed her. Maybe I'm the oldest
                          codger in the group with less sailing experience than most of you, but
                          I have enjoyed my MJ for nearly seven years. I have found her stable,
                          fast and forgiving of even my worst mistakes....

                          I strongly recommend all of you Bolgeristas get "WoodenBoat" magazine
                          Number 114, September/October 1993, and read Mike O'Brien's article
                          `Shoal-Draft Sharpies' - Simple, self-righting, and roomy, starting
                          on page 64. Mike is a recognized authority on these subjects, and his
                          article gives loads of information on various sharpie design concepts,
                          components and performnce including several Bolger boats. There is more
                          good stuff on stability including "Surprising Stability Curves" of
                          Bruce Kirby's 31' Norwalk Islands Sharpie calculated by AeroHydro, Inc.
                          It is an excellent graphic explanation of c.g./ c.b. interaction. Look
                          carefully and you will even find mention of Martha Jane. Turn the page
                          and you will find PCB's article "A New (?) Tack for a Dipping Lug".
                          This issue is a short course education for all Bolger devotees. Enjoy!


                                              
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