An axial flow hydraulic transmission is being investigated when using such a transmission in conjunction with ship propulsion driving a propeller. The investigation covers the procedure to discern the theoretical and predicted operating points for an axial flow hydraulic transmission. Theoretical performance characteristics of the primary and secondary units are determined and actual performance is predicted based on design and fluid losses. The performance curves of each component are then overlayed, and the intersection of these curves represents the transmissions’ operating point. Since actual performance curves are highly non-linear, graphic representations provide the best way to predict actual operating points.