A self-propelled swabbing device and method for use in removing liquid to surface from within an installed wellbore casing. Since the body speed V of the vehicle VL is very low when the vehicle VL arrives at a target parking position, the vehicle VL can be stopped precisely at the target parking position. The medical procedure is performed on the heart or another organ. A plurality of modified Savonius rotors are stacked one on top of the other for self-starting and greater power output. The system can be executed on paper or in the form of computer software run locally or on a network. In this way, an even distribution of event data may be collected when the processor is allocated to multiple partitions in a logically-partitioned system.