This SAE Recommended Practice provides guidance for defining the requirements for evaluating hydraulic pumps and motors and for preparing detailed specifications for these components. The user can follow this document to set forth the pump and motor environmental and performance considerations@ establish service life and reliability goals@ and define specific evaluation tests for marine vehicle applications. Purpose The application of aerospace technology to marine vehicle systems has generated the need for more rigorous system designs and detailed specifications of components for advanced surface craft and submersible vehicles. This Recommended Practice is intended to aid in the system design process for the selection of hydraulic pumps and motors and in the preparation of specifications for these components to be used in marine applications. While this Recommended Practices identifies many parameters that must be considered in hydraulic pump and motor selection and procurement@ the user must select those that are applicable to a particular system. For example@ unique requirements applicable to deep submersibles do not apply for pumps intended for use of surface ships.