Modeling and Simulation of Planing-Hull Watercraft Outfitted with an Electric Motor Drive and a Surface-Piercing Propeller

Abstract

A simulation model for a prismatic hard-chine planing hull watercraft (V-shaped keel with constant deadrise) with propulsion based on a 3-phase induction motor connected directly to surface-piercing propeller (SPP) and outfitted with a motor rotational speed controller was investigated, tested, and tuned. The modularity of the model developed enables straightforward substitution of diverse and more refined modules, or even attachment of additional ones to obtain greater level of detail or simulate more complicated processes. Industry trends do suggest an increasing interest in all-electric ship development as well as the use of surface-piercing propellers for small or medium-size craft. All-electric drive plants offer distinct advantages due to their flexibility in arrangements, ability to eliminate reduction gears in many cases, low maintenance requirements and wide range of available sizes as well superb load acceptance and dynamic matching to changing operational conditions. Employing electric drives onboard small craft with planing-hulls that achieve significantly higher velocities where arrangements and maneuverability are of critical design issues is a theme that has received increased attention by designers in recent years. Refined speed regulation and tracking compounded by the feature to produce fairly constant torque across a broad speed (rpm) range enables using of unconventional thrusters such as surface-piercing propellers to small craft. By investigating towing tank test data series for a surface-piercing propeller, development of a numerical simulation tool for unconventional thrusters was demonstrated. The surface-piercing propeller simulation model, as an artificial neural network (ANN), was coupled with a 3-phase induction motor as prime mover as well as dynamic propulsion shaft model and proportional-integral-differential (PID) controller. The various sub-models were finally integrated with a sub-model implementing Savitsky’s propulsion resistance method and calculation of equilibrium trim for planing hull modeling. Simulations were conducted using full-scale real-world conditions for a high-speed small craft developed for leisure and sporting activities, rapid close-range transit, reconnaissance and surveying etc. The planing-hull watercraft considered is amenable to minor hull modifications in order to house a 50 kW electric motor and a four bladed surface-piercing propeller. Simulations performed allowed a full assessment of model functionality as well as level of detail.