In order to satisfy the operation requirement of the rated thrust of the propeller, the propulsion motor performs only in rated torque on the low speed, so the motor power is low.

A new equipment for simulated the performance of propeller load is introduced in this paper, it's an all digital DC torque servo system using torque closed loop and current closed loop control.

Electric motors produce maximum torque from zero RPM, and do not need this kind of propeller tuning, other than to reduce current draw or to alter boat handling.