A Procedure for the Comparative Evaluation and Preliminary Design of Marine Propulsors Available to Purchase

A systematic procedure for the design of a class of marine propulsors is described. This class of propulsors includes traditional propellers, ducted propellers, contra-rotating propellers, vane-wheel propulsors, and propellers operating with pre-or post-swirl stators. The topic of optimum propulsor load distributions is discussed. An algorithm for the determination of optimum radial circulation distributions for this class of propulsors is presented. This algorithm is incorporated in a vortex-lattice, lifting-line model for lightly to moderately loaded marine propulsors. This computer model also incorporates algorithms for the determination of minimum propeller chord lengths and thicknesses, as well as for the determination of optimum values of propeller rpm and diameter. Parametric studies and comparisons of various propulsor configurations can be readily carried out under the described model. A comparative study of marine propulsor alternatives for a given application is presented.