Propulsion, auxiliary, and electric machinery developments for surface combatants are surveyed---overall system characteristics are covered to permit a broad coverage of related activities. Prime movers in both propulsion and ship service sizes are discussed. All will demonstrate improved economy, especially at part power, and increased attention to thermal and acoustic signatures. Gas turbines are the source of propulsion power, but diesels join turbines in ship service application. Electric drives may be selected where machinery is widely separated or geometries are restrictive. Reversing motors or reversing gears will provide backing power without the inefficiencies of controllable--pitch (CP) propellers. Transmission component improvements, including surface-hardened gears and composite shafts, will increase power density. Shaftline elements compatible with contrarotating propellers may lead to significantly increased propulsive coefficients. Auxiliary machinery developments are driven by the need to improve performance in smaller, simpler packages with lower acquisition and operating costs. This encourages the development and adaption of new materials and design approaches such as composite structures, rotary screw pump and compressor arrangements, variable speed or geometry units, and molecular sieves and membrane separation for gas and fresh-water production. Ventilation system requirements will be expanded and integrated with the new demands of collective protection. The ship's service generation and distribution system will reflect the increasingly nonlinear character of electric loads. Developments will emphasize power quality and continuity in system arrangements which promote both survivability and energy efficiency. Propulsion-derived ship's service, uninterruptible power at the system and component levels, and variable-speed auxiliary motor drives reflect these thrusts.