ABSTRACT
Almost all AUVs use screw-type propellers because they are in general the most efficient propulsion devices at the operating speed of AUVs, although some vehicles, for specific purposes, may use other propulsors, for example the pump-jet as in the Marlin submarine-launched AUV (Tonge, 2000) and the gliders described in Chapter 3. As these are very much the exception currently, this chapter is concerned primarily with screw propellers driven by electric motors. It begins by defining some of the terms used in propeller design. A simple theory of the propeller action is used to develop a set of equations relating its driving motor torque and power requirements to its basic dimensions, output thrust, and thrust efficiency. Methodical test series data is used to compare the mathematical model to existing propeller designs and to illustrate the critical design parameters.
