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68867Re: [bolger] Re: Pegleg Mast

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  • Douglas Pollard
    Sep 29, 2012
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      My father made a mast for the 42ft sharpie my family had when I was a
      boy. It was hollow and it had a plug in it to a few feet above the
      partners. He cut the upper end of the plug on a long 30 degree angle
      and the lowest side of it had a 1 inch slot cut in it to let any water
      run out the bottom. The inside had been coated with a mixture of
      varnish and
      diluted pine tar. We poured more in through the slot at the bottom
      raised and lowered each end of the mast and rotated it at the same time
      so that there would be no uncovered wood in any corner. The mast was
      glued up with casein glue I think the brand name was Casamite It was
      thought to be very strong and a little more forgiving in fitting. The
      boat originally had a solid mast and I think my father was trying to get
      one up on some of the neighbors who had sharpies. When the boats were
      out fishing there was always a race home and a lot of chatter and
      teasing went on when we all got in the creek. A little speed was big
      bragging rights.
      All the boats had free standing masts so that at a mooring when
      the sails were drying the boom could not get up against shrouds. The
      sails being canvas they had to be set flying the next day after sailing
      as mildew was deadly to canvas and sunlight is deadly to mildew.
      Doug


      On 09/29/2012 11:14 AM, Eric wrote:
      > I concur. With regard to fiberglass on a mast, epoxy fiberglass has less
      > elasticity than the wood. Theoretically, if it is on the outside of a
      > mast it will take most of the strain until the fiberglass fails.
      > Fiberglassing the inside makes more sense from an engineering point of
      > view (there is less movement on the inside of the mast). Doug may be
      > correct that the weight to strength ratio compared to all wood may not
      > be good. I epoxy fiberglassed the inside of my masts to prevent rot and
      > perhaps add some strength. If I had read what Doug had to say before
      > building my masts I would not have done so. Nothing like experience to
      > point out the proper direction.
      >
      > Eric
      >
      > --- In bolger@yahoogroups.com <mailto:bolger%40yahoogroups.com>, Douglas
      > Pollard <dougpol1@...> wrote:
      > >
      > > I am setting here thinking through my probably flawed logic. It has
      > > always been my understanding that solid mast is not as strong as a
      > > larger one that is hollow. The thing being that they both weigh the
      > > same. Mr. Bolger told me that the mast compliments the lift on the sail
      > > by improving the shape of the sails leading edge. This may be true If
      > > you are using his figure eight lacing that allows the sail to revolve
      > > around the mast. So up to a point maybe the bigger diameter mast might
      > > be more efficient??? Epoxy and glass on the outside may well strengthen
      > > the mast if the weather is cool?? Epoxy softens in heat so I would not
      > > varnish the mast I would paint it white to reflect sunlight at least in
      > > the area of the splice. I built a mast for a 35 ft sail boat about 40
      > > years ago. It was rectangular in shape and I built it hollow from bottom
      > > to top with drip proof vents at the top and hollow all the way to the
      > > bottom so that air would be able to circulate up through it. I saw the
      > > boat a few years ago and she had been through several owners but still
      > > carried the same mast. I believe that fiberglassing a wooden mast is a
      > > mistake. I think a slightly larger mast that weighs the same as the
      > > fiberglassed one is stronger. All this is mostly my thinking and I am
      > > posting it only as speculation and food for thought. Doug
      > >
      > > On 09/29/2012 04:03 AM, Mark Albanese wrote:
      > > >
      > > >
      > > > Thanks for the encouragement, John. With so many steps I had to do
      > it in
      > > > 6 ounce dribs and drabs, so it took awhile to get this far. Still, much
      > > > easier than building another one. And Rick did some very nice work
      > worth
      > > > saving. Light it is. Except for this flaw, solid. Nice fittings. I love
      > > > its beautiful built in curve.
      > > >
      > > >
      > > > Here's how things looked after the accident. There is birdsmouth
      > fairing
      > > > around the outside of the lower plug. See how the glass was snapped
      > cleanly?
      > > >
      > > > **
      > > >
      > > > The original crack between the strakes is just above this break and
      > must
      > > > have been a quarter inch wide and six inches long before It stabilized
      > > > with the T88. No new damage there.
      > > >
      > > >
      > > > I cleaned up the shards, filled flush with a silica and epoxy, then
      > > > drilled stepped holes for a foot long piece of 3/4" zinc plated
      > > > all-thread. I'd thought 12" just right, long enough to reach into the
      > > > thick part of the foot, spanning the joint strongly, and not going so
      > > > far up as to create a perfect spot to snap just above the partners. Not
      > > > to mention 6" either way was about all I thought to get reliably
      > straight.
      > > >
      > > >
      > > >
      > > >
      > > > The original idea was to create nice threads in both the upper and
      > lower
      > > > sections and then screw them together, mating the faces carefully with
      > > > thick epoxy. I vaselined the metal in this first try, but hey it was
      > > > stuck for good. In the end I just stuffed as much not too thick and not
      > > > too thin epoxy down the hole as possible and stuck 'em together. Just
      > > > enough oozed out to make a good join.
      > > >
      > > >
      > > >
      > > > Here, ready for glassing.
      > > >
      > > >
      > > >
      > > > Just today I put the third coat on three layers of 12 oz. biaxial tape,
      > > > two at 45 45 straight round the joint, one spiral in between.
      > > >
      > > > It's the first time I've used this and like it rather more than the
      > > > selvage edge material. The edges will need less grinding off and they
      > > > don't unravel nearly as much as plain fabric. It doesn't go as clear as
      > > > looser fabric. No matter; maybe add a bright white racing stripe.
      > > >
      > > > This photo is of the drying second coat. At half 85 degrees; half 50
      > > > over night ( ah, Portland late summer), it needs some cleaning up on
      > > > Sunday morning and waiting till late next week for the Raka to mostly
      > > > harden.
      > > >
      > > >
      > > >
      > > >
      > > > Then it's off to give it a try with anemometer in hand. Whoopee!
      > > > Mark
      > > >
      > > >
      > > >
      > > >> On Sep 28, 2012, at 10:56 PM, John Kohnen wrote:
      > > >>
      > > >>> "Dime?" "Nickel?" I guess the tale is growing with the telling. ;o)
      > > >>>
      > > >>> Most of the stress on a mast is handled by the material near the
      > > >>> _outside_
      > > >>> of the mast. Your all-thread solution is a good one for holding
      > the two
      > > >>> parts of Sage's mast together and in line, Mark, but put plenty of
      > > >>> 'glass
      > > >>> on the outside of the mast to carry the load. And make sure you've
      > > >>> sanded
      > > >>> all the varnish away before you do it. <g>
      > > >>>
      > >
      >
      >
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