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

[Wes Gardner]

Hi All,

When replacing knees, I'd use G-10. Strong, forever...


Wes

On Mon, Nov 25, 2019 at 9:49 AM John Birch via Public-List <
public-list at lists.alberg30.org> wrote:

> 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
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