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24937Re: Advice on bottom thickness of piccup pram

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  • prairiedog2332
    Jun 3 9:33 PM
      Great to hear the feedback on this discussion. I think it will all be
      very useful for perspective builders.

      Some added thoughts and observations;

      1. I think in a multichine hull like the piccup pram I like what Anders
      wrote.

      2. In a bigger hull like the Light Schooner I would go with thicker
      plywood. 3/8" MDO would be my choice.

      3. It would be easier to go with heavier glass on the bottom than adding
      another layer of plywood. Say 10 oz instead of 6?

      4. Glassing the interior would add strength but a lot of extra work.
      Thicker plywood also adds flotation but glass adds extra weight.

      5. On a single chine boat you already have abrasion resistance if the
      chine logs are on the outside which Jim Michalak seems to suggest works
      better than interior chine logs. But even then he suggests some tape
      over the chine logs.

      6. Mike Monies has chosen to no longer use Sureply but only Occume. But
      he builds boats for others on consignement from what I understand. I
      agree that is the better choice if one can afford it.

      Nels












      --- In Michalak@yahoogroups.com, Martin Houston <mtnridr13@...> wrote:
      >
      > Glass surly does add weight, but it also adds streangth. I tend to be
      hard on equipment, if it is weak I will break it. I plan to glass my AF3
      inside & out. I believe It will be strong & watertight. It is big enough
      to handle the extra weight, it won't be that much. Extra thickness in
      ply would add streangth without needing extra glass & is probably the
      way to go. My boats tend to be heavy & strong but I don't car top them.
      So far none has broke.
      >
      >
      >
      > ________________________________
      > From: Mike rudder59@...
      > To: Michalak@yahoogroups.com
      > Sent: Sunday, June 3, 2012 7:17 PM
      > Subject: [Michalak] Re: Advice on bottom thickness of piccup pram
      >
      >
      >
      > Â
      >
      > I checked the patriot web site -maker of the Sureply - and the Sureply
      underlayment thickness is 5.2 -5.5 mm. I chose it because it is
      guaranteed not to have any voids in it, has good glue qualities etc.
      > I plan on fiberglassing the bottom up to about six inches up the side
      panels. May think about taking it all the way up the sides based on
      concerns that everyone has expressed.
      >
      > Plan on fiberglassing inside portion between bulkheads A&C where you
      sit and most wear and tear will occur. Wondering if I should also glass
      the inside portion of the bottom in the front and rear compartments for
      strength or if I only need to be concerned about the open area.
      >
      > Thanks everyone for the feedback and suggestions.
      >
      > Mike
      >
      > --- In Michalak@yahoogroups.com, David Calloway david@ wrote:
      > >
      > > An inch is 25.4 mm, making 6mm ply a 1/4 inch. I'd feel safe with
      5mm
      > > glassed both sides, just my 2 cents,
      > >
      > > dave
      > >
      > > On Sun, Jun 3, 2012 at 5:36 PM, Martin Houston mtnridr13@ wrote:
      > >
      > > > **
      > > >
      > > >
      > > > Or glass the heck out of it, both sides.
      > > >
      > > > ________________________________
      > > > From: Scot McPherson scot.mcpherson@
      > > > To: "Michalak@yahoogroups.com" Michalak@yahoogroups.com
      > > > Sent: Sunday, June 3, 2012 5:48 PM
      > > > Subject: Re: [Michalak] Re: Advice on bottom thickness of piccup
      pram
      > > >
      > > >
      > > >
      > > >
      > > >
      > > > Dude, that's not slightly thinner...that's a ALOT thinner. 4mm is
      just a
      > > > touch over 1/8th inch. I inch is approximately 30mm. 30 / 4 = 7.5,
      > > > therefore 7.5 mm = approximate 1/4 inch. 4mm is just over half
      that. I
      > > > would either scratch using that, or double up on every panel. That
      boat may
      > > > crumple under load.
      > > >
      > > > Scot McPherson, PMP CISSP MCSA
      > > > Old Lyme, CT
      > > > Le Claire, IA
      > > > http://www.linkedin.com/in/scotmcpherson
      > > > Sent from my iPhone
      > > >
      > > > On Jun 3, 2012, at 12:03 PM, "Mike" rudder59@ wrote:
      > > >
      > > > > David,
      > > > > Thank you. JM 's plans call for 1/4 " plywood . Sureply is
      slightly
      > > > thinner then that (4mm) so wanted to be sure I wasn't creating a
      problem
      > > > with it.
      > > > > Mike
      > > > >
      > > > > --- In Michalak@yahoogroups.com, "D.G. Cassidy" <d.cassidy@>
      wrote:
      > > > > >
      > > > > > What does JM call for in the plans?
      > > > > > I would suggest doing whatever the plans specify.
      > > > > > This is one of JM's most popular designs; if the was a problem
      with
      > > > bottom thickness, he would have corrected the plans long ago.
      > > > > >
      > > > > > Adding extra weight will not necessarily make the boat any
      safer
      > > > (though it will make it harder to get on the roof of a car). That
      being
      > > > said, a protective layer of fiberglas on the bottom is a good idea
      of you
      > > > are going to be doing a lot of beaching, using concrete ramps,
      etc. (6 oz.
      > > > cloth is sufficient for this purpose).
      > > > > >
      > > > > > Holding weight is usually not the problem with thin bottoms.
      It is
      > > > puncture resistance. If it is something that keeps you awake at
      nights,
      > > > simply do not walk around in the boat when it is out of water and
      you
      > > > should never see a problem (a good idea with any plywood boat).
      > > > > >
      > > > > > David C
      > > > > >
      > > > > > On Jun 3, 2012, at 9:58 AM, Mike wrote:
      > > > > >
      > > > > > > Got sidetracked on my build of piccup pram by some health
      issues but
      > > > getting back on track now and should finish tie wraps of panels so
      I can do
      > > > the fillets on inside seams by next week. I've used Sureply
      plywood
      > > > underlayment (4 pr 5 mm thickness).
      > > > > > >
      > > > > > > I would appreciate any advice regarding the bottom thickness
      in the
      > > > area that you sit in. I thought about doubling up the thickness by
      just
      > > > putting in another a layer of the sure ply in that area since it
      will get
      > > > the most abuse or possibly just putting a layer of fiberglass
      cloth and
      > > > resin on that open area.
      > > > > > >
      > > > > > >
      > > > > >
      > > > > >
      > > > > >
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      > > > > >
      > > > >
      > > > >
      > > >
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      > > >
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      > > >
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      > > >
      > >
      > >
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      > >
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