Replacing rotted wood sandwiched between FG.

J

jmas

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The 30 gal fresh water tanks on my boat sit on 3/4 thick plywood shelves in the engine compartment.
The wood under one of the tanks has rotted badly.
I have removed all the rotted wood and the rotted wood that was sandwiched between fiber glass uprights that supported the plywood shelf.
The openings that I have to fill are about 1/2" wide x 6" long x 4" deep. Should I use Foam or resin. Any suggestions would be appreciated.
 
Google "pour a transom" and look at a product by Seacast .... I have not used it but it looks like it may be what you are looking for. Not sure if Boatfix has it.
 
quote:
Originally posted by psalzer

Google "pour a transom" and look at a product by Seacast .... I have not used it but it looks like it may be what you are looking for. Not sure if Boatfix has it.

Click to expand...

Thanks Pete, Looks like t would do the job.
I will check with local Fiberglass supplier to see if they have something comparable.
 
Joe, it might be stronger and easier to just rebuild the shelf. If you've worked with f glass before, laminate a new plywood shelf and install, or consider the nylon/composites?
There's a simple large paperbound book that will show you how- Fiberglass Boat Repair & Maintenance, <$5 at worst marine, #002-550
Buzz
 
I'm not a fan of seacast. You don't build a boat that way to begin with because you end up with too much weight in the wrong places. There is a reason mfg's don't do that, and its not just about cost.

That said, for the small dimensions posted, I think I might jut fill with resin myself, but you can't use just any ole resin as that much in a small space is going to generate a LOT of heat if you use a product not designed to cure slowly. If you can't find a small small amount of seacast or don't know what your doing in choosing an appropriately slow cure formula, then just bedding wood there would be more than appropriate, after all you still need to put a shelf back as well.

Before you use wood again, you need to determine the manufacturing flaw that caused it to sit wet in water and cure that. If the tank just sits on the wood and can EVER get wet, that's a huge design flaw. You could possibly put the tank back down thin strips of plastic to allow air ciruculation. Look, its not just bad for the wood, it will rot your tanks too if they are aluminum or any other commonly used metal. That area MUST not get wet. Any wood used should be pickled first in CPES, then sealed with fiberglass completely. The wood rotted because the mfg used a cheapo method of not sealing the wood. For a shelf you don't want to use foam, not strong enough. Ply is good, solid pieces of hard wood are even better. Done right, you won't have to touch again in your lifetime.
 
Ghost, The tank is Polyethylene. I think water slowly and steadily leaked from a fitting near bottom of tank and eventually caused the rot. Starboard engine blocks the view of bottom part of tank, so I missed it.
I'm thinking of shoving some chopped glass fibers in the openings to take up some space and pouring in the resin to fill the gaps.
I guess Sea cast would do the same thing. I definitely will cap the tops of the uprights with glass cloth. I have a pc of 3/4 tan Starboard in the shop that would make a nice shelf. Ill post some pix.
 
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