All that sand in the bilge!

I got this off the A30 list, and wanted to capture it here for later reference – Thank you David. On Laughing Gull, I have done the aft end, but not he bilge under the batteries. This is next.

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—– Forwarded Message —–
From: David Van Denburgh <denburgh@andrews.edu>
To: Jonathan Adams <laughing_gull@verizon.net>; Chip Dance <chipdance01@gmail.com>; Chip Dance via Public-List <public-list@lists.alberg30.org>
Sent: Wednesday, March 2, 2016 10:53 AM
Subject: Re: [Public-List] 1975 bilge leak

Here is my experience – taken from my blog – about the cement/sand in my bilge and the repair:

In the area just forward of the aftermost floor, there was a piece of exposed ballast and aft of it a cement-like material intended, I suppose, to keep the ballast in place and the fill the aft area of the keel.

Water had apparently leaked through this area for some time because a previous owner installed a drain in the bottom of the keel just aft of this position.  Once I’d vacuumed the junk out of the bilge, I noticed a hole had been drilled down through the cement, and after rodding it out with a screw driver I was able to see through to the drain in the keel.  I’m not too keen on having a exposed fitting mounted to the bottom of the keel where it could be damaged or ripped loose in a grounding, so I will eventually remove it and install a garboard drain even with the bilge bottom.

I mixed up some epoxy and applied a thin coating over the exposed material in the keel as an initial seal.  Once it was tacky, I mixed up epoxy thickened with colloidal silica and used it to fill in some of the larger gaps.  Atop that I laid a layer of fiberglass cloth.  Although that provided some measure of protection to that area, it left an irregularly shaped bilge, so I cut a couple pieces of blue DOW styrofoam board to fit and fill the bottom of the bilge, creating a flat surface that sloped slightly forward from the aft portion of the bilge.  I then covered the area with a layer of 1708 biaxial cloth that attached well up the sides of the bilge, creating new bilge bottom and sealing the area beneath.

http://alberg30project.blogspot.com/2012/07/having-lot-of-other-stuff-to-do-canvas.html