A stiffened mandrel used in the manufacture of a composite tubular. The mandrel is placed on a filament winding machine and is comprised of an outer and inner shell. A pressure source is connected to the mandrel to exert a tensile force on the outer shell to stiffen the mandrel and thereby prevent sagging and bending of the mandrel. The stiffened mandrel allows for the manufacture of a composite tubular without undesirable flexing, wrinkling, or contamination of the uncured composite.