Propulsion Machinery Considerations for Contrarotating Propeller Systems

Abstract

Contrarotating (CR) propellers offer one attractive solution to meeting the needs for higher power, more efficient ship propulsion. A planetary second-reduction gear system is proposed to provide the CR energy to a pair of propellers from a conventional turbine power source. The concentric line shafts, bearings, and lubrication system are discussed as vital components to a CR system. Some favorable full-scale operating experience has been obtained on all components except a high-power second-reduction planetary gear operating in the CR mode. The use of a CR propeller system should have a significant economic impact on the powering of ships.