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Old 11-11-2007
dohenyboy dohenyboy is offline
all these confusing ropes
 
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Can I build a fiberglass tank inside leaking metal tank?

I appreciate the knowledge base of the forum members, so I am throwing out this question.
Boat has leaking metal water tanks. I can't remember if they are aluminum or galvanized. The leaks are probably not very big, because the tanks seem to hold water to some degree when the bladders (PO installed bladders) broke last year. I am ready to bite the bullet and cut open the teak & holly to do it right if necessary. Bladders just don't provide the capacity and reliability I want. Since the boat is located far from my usual haunts, I am thinking of the second best way to do it. Obviously the best way would be to get exact measurements and have new tanks professionally fabricated, but this would be very expensive in terms of shipping not to mention the customs duty this caribbean island imposes. And no matter how exact the new tanks are made, there would be some fitting and adusting to make them snug.
The tanks are pretty big, and conform to the bottom of the hull (with a layer of insulating foam), so they are the shape of 1/4 of a cylinder.
What I am thinking about is cutting off the top of the metal tank, leaving about 1" all around on top to fit a lid. Then I was thinking of laying down, inside the tank, two layers of heavy roving with West Epoxy (available locally) and building in baffles as well. Then I could fit a lid of fiberglass on the top. I suppose I would chemically (acetone) clean the metal and rough it up so there was good adhesion, although this is probably not critical. The existing metal tank would provide strength so that the fiberglass would be primarily to seal.
In fact if I do it this way I might not have to cut up the floor. I might be able to access it all through the existing access doors. This would save me a week of work.
Does anyone have thoughts about this? Will this work or will I just create a mess? Is epoxy okay for potable water tanks or do have to put on a coat of another epoxy?

Last edited by dohenyboy; 11-11-2007 at 08:56 PM. Reason: grammar
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