In case you pondered on how exactly to go on about making your personal propulsion device… search no beyond the work by Rulof Maker. His Scuba Propellers allow you to move in the water without much effort.
He simply builds a couple of propeller gadgets which he affixes to what had been high-top running shoes. Starting with a couple of aluminum beer containers, a mill, 2 24V 4k rpm motors, doorway pistons, and vinyl fabric tube. The engine and piston is placed into beer can and is closed with silicone epoxy. Next 6cm. propellers are attached to the tip of piston.
Two12v battery power with a relay button and reed shift are linked with connected copper wires. Thie setup is laced in huge PVC pipe to keep the batteries and store them dry.
The project is done by affixing the motors to the backside of a couple of high-top shoes.