[Public-List] Backstay Knee Rot - prevention and fix

[John Birch]

Hi Andrew, et al,

The backstay chainplate knee has a known and established builder's defect.
When constructed, they cut the glassed in top off the chainplate before
fitting the deck, exposing the plywood to leak vulnerability.
Doubtless this was to ensure the knee didn't obstruct the placement of the
deck. 

If you use plywood again (recommended), simply glass over the top of the
knee, and fillet the knee to soften (radius) the curve at the knee / hull
interface. 

For those whose knees are in good shape, I recommend using Marine Tex epoxy
putty and sealing the top of the knee in place. That is what we did on our
A-30, as well as our A-37.

The builder should have sealed the knee at the top, but didn't, doubtless
due to the production schedule which was intense at the time. In its heyday,
A-30s were coming out of the molds at a rate of 3 times a week.

Hope this is helpful.

Cheers,

John

 

-----Original Message-----
From: Public-List [mailto:public-list-bounces at lists.alberg30.org] On Behalf
Of Andrew Johns via Public-List
Sent: November 25, 2019 9:26 AM
To: Alberg 30 Public List -- open to all
Cc: Andrew Johns
Subject: [Public-List] Backstay Knee Rot

Good Morning All,
While we are on the subject of cautionary tales... I would like to mention
what I found when removing our backstay chainplate.  On the outside, the
knee looked great, nicely pained with no signs of anything abnormal.

When removing the chainplate, I found loose bolts and the plywood used to
create the knee was entirely rotted out inside its fiberglass covering. I
suspect ignored leaks between the deck and chainplate contributed to its
demise.

I'm planning on opening up the knee this spring and replacing it with
either fiberglass board, Coosa or some sort of nonwood composite.

Hopefully, this helps someone else.  Maybe pull one of the bolts and hope
the plywood doesn't come out in liquid form!

Andrew
ECOLA #104
_______________________________________________
These businesses support your Association:
http://www.alberg30.org/store/A30supporters.html
Please support them.
_______________________________________________
Public-List mailing list
Public-List at lists.alberg30.org
http://lists.alberg30.org/listinfo.cgi/public-list-alberg30.org