plywood fuel tanks

I wnat to increase the fuel capacity of my lobster boat and I want to built epoxy covered diesel fuel tanks.*I saw the suggestion on one of the Gougeon's brother ( west system) boat building book. anybody having any experience with epoxy covered plywood fuel tank

Only to know that the "last" usually top seal will be difficult , unless the man holes are large enough to actually glass thru. And big home made man holes are then hard to seal.

Diesel is tough to seal!!!

With all the fish boats being regulated out of business , a used tank setup should not be that hard to find. Boats & Harbors and a $15.00 add?

FF

thank you ..I am thinkink about plywood tnk because I can build the exact size and shape that will fit were I want to put them..but you are wright about the problem of sealing the top part..

Perhaps plywood structure with bladders might be a good way to go?* Now the plywood doesn't come in contact with the fuel at all, but you can still make pretty much any shape you want.

"... the problem of sealing the top part.."

There is no reason the top should be any more difficult to seal than the sides or bottom. If you make the top so that it fits as a "plug" and is mechanically supported by the design of the joint/seating area it should not cause any sealing issues.

Seal and glass the bottom and sides and the area in which the top will seat. Glass and seal the top by itself and when you are ready to install the top, use a thickened mixture of epoxy to complete the joint. You can screw it in place then lap the joint with cloth and you will have a top to side connection that is probably less likely to leak than the bottom or sides unless you designed them the same way.

If one has made up his mind to go "plywood" then I think Chris has hit on it. Years ago I worked on a project for one of the big pineapple companies. The problem was how to ship pineapple juice in bulk but in a container that could be palletized, moved easily and reused many times over. The solution was plywoood containers that "knocked down" (folded) easily and could be shipped, economically, back to the filling plant empty. (They didn't have to be cleaned all the time either.) A bladder was used and the program was very successful. The dimensions of the "box" was 4 feet cubed.