A propulsion system for use by a swimmer in both on-water and under-water applications, the system comprising: (a) at least one power supply unit (16, 16A) attachable about a sleeve, suitable for being secured about a forearm of a swimmer; (b) at least one corresponding propulsion unit including a motor and an impeller, the motor in electrical communication with the power unit (16, 16A), said propulsion unit within a housing, said propulsion unit having a bracket pivotally securing said propulsion unit to said sleeve about a pivot element defining a pivot axis, said unit extending in a direction laterally offset from said forearm and distally away from the head of the swimmer; wherein said housing of said propulsion unit defines a thruster having therewithin said impeller, from which a hydrodynamic thrust results; (c) control means for said power and propulsion units (16, 16A, 30), said control means including: (i) means for controlling pitch of a longitudinal axis of said propulsion unit relative to the sleeve by rotating the propulsion unit about the pivot axis, such that said means for controlling pitch is suitable for being operated by extension or flexion of the wrist of a swimmer, when said sleeve is secured about a forearm of said swimmer, said pivot axis being parallel to the axis of the wrist when performing extension or flexion, said means including said pivotally secured bracket; and (ii) means for control of power provided by said power unit (16, 16A) to said propulsion unit, each of said power control and pitch controlling means positioned for ease of accessibility by a hand of the swimmer. (a) at least one power supply unit (16, 16A) attachable about a sleeve, suitable for being secured about a forearm of a swimmer; (b) at least one corresponding propulsion unit including a motor and an impeller, the motor in electrical communication with the power unit (16, 16A), said propulsion unit within a housing, said propulsion unit having a bracket pivotally securing said propulsion unit to said sleeve about a pivot element defining a pivot axis, said unit extending in a direction laterally offset from said forearm and distally away from the head of the swimmer; wherein said housing of said propulsion unit defines a thruster having therewithin said impeller, from which a hydrodynamic thrust results; (c) control means for said power and propulsion units (16, 16A, 30), said control means including: (i) means for controlling pitch of a longitudinal axis of said propulsion unit relative to the sleeve by rotating the propulsion unit about the pivot axis, such that said means for controlling pitch is suitable for being operated by extension or flexion of the wrist of a swimmer, when said sleeve is secured about a forearm of said swimmer, said pivot axis being parallel to the axis of the wrist when performing extension or flexion, said means including said pivotally secured bracket; and (ii) means for control of power provided by said power unit (16, 16A) to said propulsion unit, each of said power control and pitch controlling means positioned for ease of accessibility by a hand of the swimmer. (i) means for controlling pitch of a longitudinal axis of said propulsion unit relative to the sleeve by rotating the propulsion unit about the pivot axis, such that said means for controlling pitch is suitable for being operated by extension or flexion of the wrist of a swimmer, when said sleeve is secured about a forearm of said swimmer, said pivot axis being parallel to the axis of the wrist when performing extension or flexion, said means including said pivotally secured bracket; and (ii) means for control of power provided by said power unit (16, 16A) to said propulsion unit, each of said power control and pitch controlling means positioned for ease of accessibility by a hand of the swimmer.