[Public-List] Mast Beam Fix - other notions

[Roger L. Kingsland]

Michael,

Sounds like a great plan.  I seem to recall from structures class a few
decades ago that the loads on a "simple" beam are greatest at the top, which
is under compression, and bottom, which is in tension, and, other than the
force necessary to hold the top and bottom apart, there is minimal stress in
the middle.  Point being that, if you add layers of FG cloth (or even some
of that fancy carbon fiber) top and bottom after you reglue the beam (might
have to decrease the beam depth accordingly), you will probably have a beam
stronger than the original without too much additional effort.

Just a thought.

Roger 148


-----Original Message-----
From: public-list-bounces at lists.alberg30.org
[mailto:public-list-bounces at lists.alberg30.org] On Behalf Of Michael
Connolly
Sent: Wednesday, March 05, 2008 11:36 AM
To: Alberg 30 Public List -- open to all
Subject: Re: [Public-List] Mast Beam Fix - other notions

Hello Bobby,
   
  I know that I am the Lone Ranger on this approach, but I am planning on
removing my original laminated beam and re-gluing with Epoxy Resin and then
reinstalling into the boat.
   
  My hull number is 133 and Brain Zinzer has hull number 132.  Brian's mast
beam is not quite as bad as mine and he is waiting to see how my project
turns out to see if he would proceed as I plan to.
   
  I have several reasons for attempting the repair this way.  No additional
holes in the beam, original appearance, no appreciable weight added, ability
to inspect the top surface of the beam for deterioration and perhaps to fill
the two holes drilled into the beam for the center two mast step bolts.
   
  My observations have been that it is the center section of the beam,
between the door jambs, that sags the most.  I have been told that the beam
does not extend to and is not fastened to the hull below the gunwale, thus
if/when it sags it should not push outward on the hull, at least not
appreciably.  I have also been told that the beam, at least on non-liner
boats, is just bolted to the bulkheads by either four or five bolts on
either side of the door jambs.  There is some tabbing to the coach ceiling
but that is already loose on my boat.
   
  The cost for this repair should be that of the Epoxy Resin = $60.00 plus
my labor and perhaps new bolts for the bulkheads.
   
  Michael

Bobby <capricebob at yahoo.com> wrote:
  Hello Fellow Albergers

Spring is approaching and I'm starting to make a list of projects for
Caprice #388 and one I was entertaining was the mast beam fix. I don't think
I have too much if any sagging but it looks like the beam is starting to
delaminate. The aluminum plates fix designed by Bruce Rankin seems pretty
straight forward although the cost for aluminum has gone up. I was recently
quoted $400 for the pair plus shipping. 

Another notion I had that would be relatively easy would be to install
wooden supports maybe 2 1/2 by 2 1/2 and run them from the beam all the way
down to the hull and just bolt them to those posts that from the door way to
the front cabin. Has anyone attempted this and would this help mitigate the
problem with the mast beam? 

The problem I have is that I'm not sure what the potential problem is
actually. Does the delamination cause sagging in the middle, pushing out the
sides, both, or some other issue? 

Any thoughts would be highly appreciated. 

Thanks,
Bobby 


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