While the implementation of azimuthing propulsors powered by internal electric motors (often called "podded propulsors") into the commercial ship market has been swift, the understanding of their hydrodynamics through research, particularly in the area of maneuvering performance, has been very limited. This thesis research investigates the steady and unsteady dynamic maneuvering forces associated with an azimuthing podded propulsor, and provides supporting theoretical insight toward understanding their mechanisms and prediction. Because of the wide range of potential applications of azimuthing podded propulsion in the marine field, dynamic force phenomena applicable to maneuverability of both large and small scale vehicles are investigated. These include quasi-steady vectored maneuvering forces, of importance to all maneuvering vehicles or ships, as well as unsteady or transient maneuvering forces, which have more significance to the maneuverability of smaller vehicles, particularly for precision control applications. The ultimate goal of the research is to provide a comprehensive understanding of the maneuvering forces associated with an azimuthing podded propulsor, such that future maneuvering and control applications, and computational fluid dynamics studies in the field, can be appropriately focused. The research efforts are focused in four main areas. First, a number of relevant dynamic models for the maneuvering of a surface vehicle with an azimuthing propulsor are developed. Second, an extensive test program measures and characterizes the nature of quasi-steady vectored maneuvering forces associated with a podded propulsor in azimuth to ±180⁰ for the entire range of forward propeller speeds, as well as unsteady or transient maneuvering forces due to rapid changes in azimuth angle or propeller rate.
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