Development of bespoke design methodologies to make them recognizable to designers working in a speci c engineering domain is a requirement to making them more acceptable. Application of domain-speci c design methodologies by industry will promote the adoption of systematic design, bringing with it the inherent advantages of adopting a systematic approach. This paper examines the development of a domain-speci c methodology for uid power systems, a specialist design discipline within mechanical engineering, and describes the implementation of the methodology within a computerized design support tool. Key technical and methodological features of the design tool are described with speci c reference to the knowledge capture and representation processes employed. As such, the need for design theory to be adapted to meet the needs of speci c engineering domains within industry is demonstrated.