Integrated probabilistic design of marine propulsors to minimize lifetime fuel consumption

Abstract Marine propellers are typically designed to achieve optimal performance at a single or a few design points. It is well understood that the performance of marine propulsion systems decays at off-design conditions, where the system operates for the majority of its life, where fuel consumption rates are high and the system as a whole operates at lower efficiencies. This paper presents a novel integrated design methodology that considers the propeller, prime mover, and vessel as one integrated system, and considers the probabilistic operational profile of the vessel, to minimize lifetime fuel consumption. The proposed design methodology represents a new approach to evaluate the tradeoffs between different design objectives and constraints by considering the system performance characteristics along with probability of occurrence, and hence allows for global optimization of the propeller geometry. Results are shown for a pair of fixed-pitch propellers designed for a twin-screw naval combatant craft. System performance for a design obtained using the proposed methodology is compared with designs obtained using traditional point-based design approaches. This methodology can be easily extended to investigate the effects of variations in resistance, operational profile or additional performance criteria, such as safety during extreme operations, lifetime carbon emission, and life cycle costs.