Composite materials offer a unique opportunity for offshore applications were high stiffness and light weight are the major design criteria. Deep water drilling and production riser are one area where detailed design studies of potential composite applications are required. This thesis outlines the essential considerations for multiaxial load bearing structures. The work focuses on the analytical experimental characterization of prototype tubes and the development and implementation of an optimization technique to study the design of prototype and full scale components. A progressive failure criteria in the finite element procedure is utilized to accurately capture detailed failure behavior of composite tubes and correlate analytical results with experimental data. Once confidence in the analytical approach is gained and design requirements are established, the developed design optimization methodology is applied to the optimization of a potential rise tube for a tension leg platform (TLP). Further analyses are then used to select a final optimized design and confirm its capabilities.