A "clean sheet" perspective unbound by current design programs has revealed a critical finding in determining ship power needs. In discussing the results of a comprehensive study of ship propulsion alternatives completed and released this spring, Howard Fireman, the Navy's chief naval architect, said that missions and required operational performance, not ship displacement, are the most important factors in evaluating options for propulsion architectures that produce the right "energy demand signal" for various ship types.
By that measure, nuclear power may be most efficient for ships with constant high demands for energy. Ships with lower energy requirements may operate more efficiently with a hybrid architecture such as a combined diesel-gas turbine plant and a hybrid transmission system-for example, a single shaft with a secondary propulsion unit.
The study, supported by the Naval Surface Warfare Center's Carderock Division and the Office of Naval Research, builds on two 2005 studiesan economic analysis aimed at reducing ship energy consumption and a detailed CNO-directed analysis of various ship technologies-neither of which looked at missions.