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Re: Moving rudder & its effects

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  • donm172001
    In a light boat the center of resistance is not fixed. You can easily add more weather helm or lee helm simply by moving forward or backward in the cockpit
    Message 1 of 2 , Jan 4, 2006
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      In a light boat the center of resistance is not fixed. You can
      easily add more weather helm or lee helm simply by moving forward or
      backward in the cockpit which in effect changes the center of
      resistance. You can, in fact, steer the boat without a rudder simply
      by changing your position fore and aft. Try it the next time you are
      out sailing in light winds and need a little bit more of a challenge.



      --- In bolger@yahoogroups.com, "Joe Cronley" <joe@c...> wrote:
      >
      > In my continuing study of the His & Hers/Singlehand Schooner, I
      have come to
      > the following conclusions:
      >
      > 1) I will not scale the boat up, 19 feet is long enough for four
      boys and an
      > adult. I am reconfiguring the cockpits to make more of an open
      racing dinghy
      > style sidedeck/gunwale (think of a 470 or 505, even the
      spectacular Flying
      > Dutchman) . Current plan is to groove plywood in order to make
      longitudinal
      > curved sections and bend them into place in cockpit fore & aft of
      mainmast
      > step & bulkhead. Will experiment with some 1/4" ply first. This
      would also
      > be sealed (airbagged if I can do it economically) in order to
      provide
      > flotation and would be positioned to float the boat high on its
      side and
      > minimize swamping.
      >
      > 2) The rudder structure is too complex. While the (sic) foil
      itself is very
      > straightforward, it's mounted in a lifting trunk that comprises the
      > rudderhead, shaft and foil on a lifting stage to allow beaching and
      > trailering. A simpler solution is to create an outboard rudder:
      simpler to
      > construct and mount, can be constructed as a folding rudder,
      allows more
      > cockpit room. In appearance, it would be rather like a tiny Nova
      Scotia
      > pinky schooner: outboard rudder on a double ended boat with long,
      curved
      > tiller.
      >
      > While I haven't scaled it, this would place the rudder perhaps as
      much as a
      > foot aft of the current design. Due to the sternpost rake, the
      bottom of an
      > outboard rudder would nearly meet the bottom of the designed
      rudder. My
      > thought is to duplicate area of the rudder.
      >
      > Question: While the placement of center of effort and daggerboard
      is
      > critical for helm performance, how could I predict how this action
      would
      > affect handling? Ast the center of effort and center of resistance
      are
      > already defined and remain fixed, the rudder should just be a
      trailing foil
      > and not affect balance. Would likely affect control response under
      sail and
      > may even allow a smaller rudder, but I can't see it inducing
      weather or lee
      > helm. Perhaps it would limit control under short sail (reefed
      main) as CE
      > moves forward? Not even sure I would reef this boat, just drop
      foresail and
      > proceed under somewhat balanced main & Jib.
      >
      > Joe Cronley
      >
      > 678-352-8983
      >
      > cel 404-295-5712
      >
      >
      >
      >
      > [Non-text portions of this message have been removed]
      >
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