Optimization using shrouded impellers on the side and one extra centrifugal water pump

I am an Angolan, southern Africa.

I have a design for a submersed water pump for river flows working only with the river flow.
We can fabricate simple machines in Angola, and cylinder/pistons assembly is easy.
Two cylinders, one with 1 meter diameter and the other 0.2 m/diameter. Pistons are in the same shaft. Area ratio is of 25 X. Pressure ratio of 25X.
The bigger cylinder has a diffuser of a diameter of 1.5 meter in both ends and is open on both sides.
When we submerse it in the river flow, the water flows in and pushes the piston. On the other end of the cylinder the water flows out in the direction of the river flow.
It is a shrouded cylinder with a diffuser and two half diffusers, like impellers to move the system around.
The piston pushes the second piston, in a closed cylinder (0,2m/d) and pressures water. The inlets and outlets of this double side cylinder have retention valves to control aspiration and discharged of the cylinder.
The cylinders rotate on its axis, enabling continuous cycles.
It is a water pump that uses only the river water flow.