Abstract: The fabricated pressure vessel is a filament wound structure having a connt winding angle assuring maximum filament utilization efficiency and also having polar end openings of different sizes. Fabrication of the vessel includes a first step of forming a structure having filament windings and identically-sized polar openings equal to or less than the smaller of the openings dictated by the design. Identical openings permit the constant winding angle. In the winding operation, wafer-like mats formed of dimensionally-stable material are interspersed between the filament layers at each polar end. In the final step, the polar openings then are machined to the desired size. The interspersed mats encircle the polar openings and reinforce the polar regions.