[Public-List] Mast beam.

[Jonathan Bresler]

Greg,

On Salacia, the mast beam was replaced with G10 fiberglass
http://svsalacia.blogspot.com/2016/07/final-stages-of-alberg-30-mast-beam.html
Looking at the original mast beam, the laminates run horizontally, like a
layer cake.  Downward pressure from the rig tension and weight of the
mast tries to flatten the beam by removing the upward arch.  To flatten the
beam the various layers must slide a bit which means that the glue
has to hold the layers from sliding against one another.  Guess that it was
made like a layer cake cause its possible to bend each piece to form
the curve of the desired arch.  As the arch flattens, the wood is returning
to its original shape.

Perhaps it would have been better if Whitby had cut the arch from sections
of wood sufficiently tall and then laminated them front to back.  Then
in order to sag, the wood would have to deform rather than return to its
original shape.

Using a nice wood facing, fore and aft, to cover G10 or aluminum plates in
the center of the sandwich might look nicer.

Jonathan

On Wed, Dec 19, 2018 at 8:36 AM P Seidel via Public-List <
public-list at lists.alberg30.org> wrote:

>  Greg;When you take the aluminum plates off please save them.  They could
> be used on several race boats that currently do not have the support
> brace.  We can cover the cost of shipping.Thanks tons.Pat SeidelRC
> RacingChesapeake A30 Assoc
>     On Wednesday, December 19, 2018, 6:59:12 AM EST, Greg Dawson via
> Public-List <public-list at lists.alberg30.org> wrote:
>
>  Dear all
> This winter I intend to laminate a new mast beam.  Currently we have two
> very ugly aluminum plates bracing the original beam.
> Does anyone have knowledge of this and if yes what material would you use?
> I'm thinking of 1/4 inch oak or ash strips to build the laminate. Also what
> glue would you use in the construction and why.
> Any help appreciated and best wishes to all.
> Greg #348
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-- 
Jonathan M Bresler
S/V Constance Alberg 30 #262
Annapolis/Eastport MD