This thesis presents the design and development of a new detachable shell component for Paralympic sit skiers. The research is aimed at enhancing the aerodynamics of a sitski without compromising stability, safety, or the user’s ability to control the ski. With user needs as a central focus, the design process began with an in-depth contextual and user experience analysis. This led to an extensive programme of requirements. By utilizing 3D scans of athletes in their ski, a CAD model of the shell was developed and iteratively refined using CFD simulations. 2 designs were created using CFD simulations and validated in a wind tunnel. The final shell component is 3D printed in flexible TPU for a built-in safety mechanism in the event of a crash. To validate reproducibility, the design approach was successfully applied to a second athlete. The finalised CAD models are printed for snow testing.