It sounds like you are using fiberglass chopped strand mat.

According to the Raka web site "These mats have a binder designed for polyester resins and though they are sometimes used with epoxy resins with satisfactory results, the binder may cause clouding and prevent thorough wet out."

If it is mat, I think you will end up with a heavy kayak and I would not use it on the exterior surfaces. It is difficult to get smoth.