[Alberg30] A30 mast support beam

Daniel Sternglass dans at stmktg.com
Fri Feb 15 11:12:46 PST 2002


George Dinwiddie wrote:
> 
> Mike Lehman made the template that Washington Aluminum digitized.  He's
> in France right now, so he can't jump in and say how he did it.

Dan,

We made our own template 15 years or so ago, and then made the brace out
of stainless steel. We ended up with a weldment that had a bottom as
well as two sides. If you plan on making the brace yourself, let me know
and I can probably recall some more details.

Here are three things I remember about making the cardboard template
that we used:

1. Jack the existing brace into the -final- position that you want it
before measuring and drawing. I think we used a screw-type house jack
and a 4 x 4 down to the topo of the keel through the floor hatch.

2. Make sure to leave a 1/8" gap between the top edge of the brace and
the "ceiling" (e.g. the bottom of the deck. This is -very- important, in
order to avoid cracking of the deck gelcoat while the brace flexes under
load. Probably should have a 3/16 gap if you make the measurement this
with the mast off due to the lack of compression.

3. Once everything is in place, you can trace the curve of the bottom of
the laminated brace, and use that as the starting point for fine tuning
the curve of the top, since the top and bottom are -nearly- parallel
(but not quite since there is delamination).

Also, I seem to recall that we piloted the bolt holes in the metal brace
with small holes on one side only, and drilled the actual holes with the
welde brace (or plates maybe in your case) jacked in place.

Hope this helps,

--Dan Sternglass
dans at stmktg.com
Watcher of the Skies, #201, 1966, Cayuga Lake, Ithaca, NY
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