[Public-List] Mast beam - Welded channel section

[Daniel Sternglass via Public-List]

Hello,

On the subject of the mast beam... A few years after we bought our 
(non-liner)  boat in 1986, we had to make a doubler for the mast beam. 
My boat partner, at the time, and I had the good fortune of working at 
Borg Warner automotive, advanced development labs. One of the machinist 
was kind enough made us a stainless doubler, like the two aluminum 
sister-plates, but with a curved piece of stainless welded across the 
bottom. The channel section gives it great rigidity. Admittedly, the 
labor for this would have been very expensive if not for the g-job from 
a machinist friend of ours.

It is certainly more fabrication work than the plates, but I believe it 
is far stronger. We jacked the beam up before drilling the through 
bolts, and more than 25 years later the top of the brace has not shifted 
relative to the cabin-top.

One question -- Back in the day, plain old elastomeric caulk was 
recommended for the shroud chain plates, and we've been doing that for 
30 years with no evident problems. I tighten the (5/16") chainplate 
bolts as-needed every year, and they are solid. I take that to indicate 
that there is no evidence of rot in the support structure. Does that 
seem reasonable?

Thanks,

--Dan Sternglass
Watcher of the Skies, #201, 1966
Cayuga Lake, Ithaca, NY

dans at stmktg.com
mobile: +1607-592-8012

Strategic Marketing Associates
403 Highgate Road
Ithaca, NY 14850