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RE: [Michalak] Re: Twin Leeboards

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  • John Trussell
    I had a Dovekie with a bow centerboard. It worked fine in shallow water. It somewhat offset the lee helm which developed when I reefed. However, if you are in
    Message 1 of 28 , Apr 4 3:30 PM
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      I had a Dovekie with a bow centerboard. It worked fine in shallow water. It
      somewhat offset the lee helm which developed when I reefed. However, if you
      are in the habit of heading up in a puff, be aware that the bow centerboard
      will resist heading up-best to ease the sheet.



      JohnT



      _____

      From: Michalak@yahoogroups.com [mailto:Michalak@yahoogroups.com] On Behalf
      Of jhargrovewright2@...
      Sent: Thursday, April 04, 2013 6:18 PM
      To: Michalak@yahoogroups.com
      Subject: Re: [Michalak] Re: Twin Leeboards





      Tim Anderson... I admire the Black Skimmer and the information. What swamp
      do you reside in? Can you add any comments experience with the bow dagger
      board. That is an unusual place for a foil and I wonder how and why Bolger
      came up with that arrangement. Any info would be appreciated. JIB

      ---------- Original Message ----------
      From: Tim Anderson <naturalist71261@...
      <mailto:naturalist71261%40gmail.com> >
      To: Michalak@yahoogroups.com <mailto:Michalak%40yahoogroups.com>
      Subject: [Michalak] Re: Twin Leeboards
      Date: Thu, 4 Apr 2013 15:47:55 -0500

      <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
      "http://www.w3.org/TR/html4/strict.dtd">
      I had twin air-foiled lee boards on my PCB Black Skimmer, i used the pivots
      that Phil used on Black Gauntlet with 1 degree toe-in. I also added a bow
      dagger board for beating in shallow water. She pointed very high so long as
      i sailed her as flat as possible. Tim P Anderson Swamp Dwelling Boat
      Builder

      [Non-text portions of this message have been removed]

      [Non-text portions of this message have been removed]





      [Non-text portions of this message have been removed]
    • prairiedog2332
      Jim drew a design called Eisbox that had a bow centreboard installed in the free-flooding bow well as an option. There is a cartoon in the files section. The
      Message 2 of 28 , Apr 5 5:19 PM
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        Jim drew a design called "Eisbox" that had a bow centreboard installed
        in the free-flooding bow well as an option. There is a cartoon in the
        files section.


        The idea was to lower it enough in shallow water to help prevent lee
        helm as the leeboard was raised. Very simple to add as you don't have to
        worry about sealing the case since it is already inside the
        free-flooding well, so it can be a very shallow rectangular box open at
        the top. The board is in the shape of a quarter circle about 18" in
        diameter. Just needs some weight added so it stays down and a control
        line leads from a tab added to the aft end leading up to a turning block
        at the bow and then back to the helm to raise it to the desired height
        and locked into a jam cleat.


        Eisbox has a 5 ft. deep leeboard so as it is raised in shallows will
        quite likely introduce lee helm and spoil upwind capability. So as the
        leeboard is raised you lower the bow board and hopefully maintain a
        neutral balance at the helm by adjusting both boards as you go along.
        The only thing is that you are restricted to 6" draft on Eisbox as it
        has a skeg ahead of the inboard rudder to protect it - which Jim doesn't
        like all that much - but the fellow who commissioned it insisted on as
        he wanted the OB to be mounted on the centreline. It was intended to
        motor more than sail in the purpose he wanted a boat for. He wanted to
        motor out offshore to fish when the winds were normally too low to sail
        and sail back home when the on-shore breeze arose in the afternoon.


        So a fellow like JIB might be interested in this information if used in
        hull with less draft than Eisbox and likes to sail in the shallows?

        Nels


        --- In Michalak@yahoogroups.com, "John Trussell" <jtrussell2@...> wrote:
        >
        > I had a Dovekie with a bow centerboard. It worked fine in shallow
        water. It
        > somewhat offset the lee helm which developed when I reefed. However,
        if you
        > are in the habit of heading up in a puff, be aware that the bow
        centerboard
        > will resist heading up-best to ease the sheet.
        >
        >
        >
        > JohnT
        >
        >
        >




        [Non-text portions of this message have been removed]
      • jhargrovewright2@juno.com
        Nels, I was not familiar with Eisbox. Interesting boat. I did not find any info on the bow centerboard but have thought about the effects/uses that it might
        Message 3 of 28 , Apr 6 6:37 AM
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          Nels, I was not familiar with Eisbox. Interesting boat. I did not find any info on the bow centerboard but have thought about the effects/uses that it might have. I think I understand the purpose and function balancing the boat in shallow water....Clever. I prefer to set up my boats with significant weather helm and rely on the rudder for a good portion of the LR.... I am just as careful building the rudder as the leeboard. I may do a centerboard again but, that is not on the list yet... Thanks for the information. That bow centerboard device has long been a mystery to me. Thanks, you have expanded my understanding of the sailboat, again.,,, I do love to sail in shallow water. At the Texas200 a couple of years ago in my Laguna....I stood on the bow of the boat....in the shade of the forward sail and followed the Matagorda Bay shore in 6" to 1' water sneaking up on the fish and other creature of the shallows. Interesting was that in displacement mode in 5"-6" the boat created a significant breaking 1/4 wave following off the transom. I was running directly down wind (10 mph) and did not have the push needed to plane. JIB
          --------------
          <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> Jim drew a design called "Eisbox" that had a bow centreboard installed
          in the free-flooding bow well as an option. There is a cartoon in the
          files section.

          The idea was to lower it enough in shallow water to help prevent lee
          helm as the leeboard was raised. Very simple to add as you don't have to
          worry about sealing the case since it is already inside the
          free-flooding well, so it can be a very shallow rectangular box open at
          the top. The board is in the shape of a quarter circle about 18" in
          diameter. Just needs some weight added so it stays down and a control
          line leads from a tab added to the aft end leading up to a turning block
          at the bow and then back to the helm to raise it to the desired height
          and locked into a jam cleat.

          Eisbox has a 5 ft. deep leeboard so as it is raised in shallows will
          quite likely introduce lee helm and spoil upwind capability. So as the
          leeboard is raised you lower the bow board and hopefully maintain a
          neutral balance at the helm by adjusting both boards as you go along.
          The only thing is that you are restricted to 6" draft on Eisbox as it
          has a skeg ahead of the inboard rudder to protect it - which Jim doesn't
          like all that much - but the fellow who commissioned it insisted on as
          he wanted the OB to be mounted on the centreline. It was intended to
          motor more than sail in the purpose he wanted a boat for. He wanted to
          motor out offshore to fish when the winds were normally too low to sail
          and sail back home when the on-shore breeze arose in the afternoon.

          So a fellow like JIB might be interested in this information if used in
          hull with less draft than Eisbox and likes to sail in the shallows?

          Nels

          --- In Michalak@yahoogroups.com, "John Trussell" <jtrussell2@...> wrote:
          >
          > I had a Dovekie with a bow centerboard. It worked fine in shallow
          water. It
          > somewhat offset the lee helm which developed when I reefed. However,
          if you
          > are in the habit of heading up in a puff, be aware that the bow
          centerboard
          > will resist heading up-best to ease the sheet.
          >
          >
          >
          > JohnT
          >
          >
          >

          [Non-text portions of this message have been removed]



          [Non-text portions of this message have been removed]
        • prairiedog2332
          As well as Dovekie and Black Skimmer Bolger added a bow board to his Whalewatcher for the same reasons - to help with helm balance. Bolger also tried to
          Message 4 of 28 , Apr 6 11:32 AM
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            As well as Dovekie and Black Skimmer Bolger added a bow board to his
            Whalewatcher for the same reasons - to help with helm balance.

            Bolger also tried to develop a bow steering design, based I think on ice
            boats? So a bow board you could adjust a bit to port or starboard would
            probably be interesting like toed in or out with leeboards. I think the
            control mechanisms quickly become complicated for the small gains in
            performance. I think at planing speeds a bow board should be raised.

            Nels
            --- In Michalak@yahoogroups.com, "jhargrovewright2@..."
            <jhargrovewright2@...> wrote:
            >
            > Nels, I was not familiar with Eisbox. Interesting boat. I did not
            find any info on the bow centerboard but have thought about the
            effects/uses that it might have. I think I understand the purpose and
            function balancing the boat in shallow water....Clever. I prefer to
            set up my boats with significant weather helm and rely on the rudder for
            a good portion of the LR.... I am just as careful building the rudder
            as the leeboard. I may do a centerboard again but, that is not on the
            list yet... Thanks for the information. That bow centerboard device
            has long been a mystery to me. Thanks, you have expanded my
            understanding of the sailboat, again.,,, I do love to sail in shallow
            water. At the Texas200 a couple of years ago in my Laguna....I stood on
            the bow of the boat....in the shade of the forward sail and followed the
            Matagorda Bay shore in 6" to 1' water sneaking up on the fish and other
            creature of the shallows. Interesting was that in displacement mode in
            5"-6" the boat created a significant breaking 1/4 wave following off the
            transom. I was running directly down wind (10 mph) and did not have the
            push needed to plane. JIB




            [Non-text portions of this message have been removed]
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