a method for the manufacture of a fiber reinforced plastic structure , comprising the steps of winding a continuous long - staple fiber impregnated with a liquid resin around a plurality of winding jigs until the resultant bundle of resin impregnated fibers attains a predetermined thickness ; setting rings tightly in place on the linear portions of the resin impregnated fiber bundle between the jigs ; and moving the tightly set rings relative to the linear portions thereby wringing the resin impregnated fiber bundle and expelling bubbles entrapped within the fiber bundle .