: My partner and I are preparing to build 17ft fiberglass sea kyaks. We were
: told that one layer of 17oz double bias stich mat with vinylester resin
: would be strong enough. We used some to erinforce cross bracing on the
: mold and noticed that it is only 1/16 inch thick. Is this thick enough to
: not oilcan in the hull?

I would not use mat alone to make a kayak, the mat acts like a glue to bind the other layers together. you should use mat first than a layer of roven woven or cloth, you said it is double stitched mat are you sure that it is not roven or cloth as with mat the stuff that holds it together is starch. or is it possible that what you have is fabmat, I used some of that to build a pram last year and it worked great but I used two layers of kevelar fab mat to get the stiffness but it still reguired two bulkheads. fabmat is mat attached to roven woven it simplifies the layup process but it is a little on the heavy side.