NOVELTY - The energy generating system (10) has a pair of vertically oriented sails (18) for opposing reciprocal swing motion in response to flow of fluid (20). A generator assembly (17) mechanically coupled to the sails generates electrical energy from the opposing reciprocal swinging motion of the sails. Each sail pitch is adjustable to promote the swinging motion.    USE - Energy generating system for generating electricity e.g. for remote cabin, construction workers, campers, or hunters at single remote site, or for powering city, using wind and or water flow.    ADVANTAGE - Sail pitch is changed at predetermined set points to improve efficiency of stroke of swinging arms. The sail and rudder combination can have a higher effective angle of attack, providing additional driving force in this portion of the stroke. The wind and water sails can be sized relative to the density of their respective flowing fluids, so that the typical energy output of the wind and water-based generators is substantially balanced, at least under certain conditions. The sail pitch and rudder pitch control systems can be configured to adjust the relative angles of these features to accommodate different wind conditions and to reduce damaging mechanical stress upon the system. The system is also relatively inexpensive to produce and operate, quick and easy to install or remove, and is relatively low-maintenance, and does not significantly affect birds, fish or other marine life, or river and air flows, since it generates electricity with no pollution emissions or fueling costs, and the swinging arms reciprocate at relatively low speeds.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method of generating electrical energy.    DESCRIPTION OF DRAWING(S) - The drawing shows the perspective view of an energy generating system in form of a hydrosail generating device mounted on a floating barge.    Energy generating system (10)    Arms (12)    Generator assembly (17)    Sails (18)    Fluid (20)