Pupa Underwater Traction

It's a teardrop skeleton covered in a stretch fabric. the traction cycle goes like this: an expandible ring grows from the front, stretching the fabric. It expands and rolls to the end of the teardrop, then colapses back and travels to the front to start the cycle again. there is always an expandible ring moving water. if the ring is wide enough, the fabric can make a "parachute effect" making this device to look kind of like a jellyfish.

in order to make this engine quiet, the force might be build on engines inside the submaine. wrapped on a Noise-cancelling wrapping.

This way you can have a silent submarine that doesen't revolves water with a propeller.