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25864Re: another Birdsmouth spar thread.....

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  • brucehallman <brucehallman@yahoo.com>
    Jan 3, 2003
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      > the spars for my Micro.

      I have also been thinking about
      this exactly, for my Micro
      Navigator. I don't know if I
      have the best solution, but
      the solution which I am leaning
      towards is as follows:

      I can buy 20' Doug Fir 2x6's in my
      local Home Depot, they appear
      strong and cheap. I plan to
      bevel both edges of two of them
      using my Skil Saw with a ripping
      guide. I will then sandwich two
      1 1/2"+ wide pieces in between, leaving
      a roughly 1 1/2" square hollow in
      the center. This will give me
      a crudely hexagonal spar, which I
      will then trim some more with an
      electric hand plane, and later
      with a belt sander.

      I plan to not bevel any edges for
      about three feet in length right
      at the mast partner, leaving the
      spar with a square cross section
      of 4 1/2" right where it needs
      strength the most.

      The middle 2/3rds of the Navigator
      mast need to be untapered and round
      to accomodate the 'jaws' of the boom,
      gaff, and battens called for on the
      sail plan. Above the top yard, I
      figure the mast can be tapered
      somewhat, removing mass from where
      it would help the most.

      I asked PCB the question: is the 4"
      untapered schedule 40 aluminum mast
      on the plans 'inside' or 'outside'
      diameter.

      He responded, I quote:

      4" outside diameter; 3 1/2" I.D.
      or, wood stave fir etc. mast like the
      original design, but not tapered. Without
      taper, the stave thickness can be reduced
      to 1 1/4" or 1 1/8".

      I am guessing that after I trim the 1 1/2"
      Home Depot lumber to a rounded cross section
      I will end up with staves around 1 1/4"

      I priced the aluminum tubing and it was
      $20 a foot, $400 total. Fir will cost
      less than $75, a no-brainer decision,
      for me at least.
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