Ship vertical propeller

Yellow disk and lower brown disk rotate eccentrically from only a motion source (pink bevel pinion). Their eccentric (value and direction) can be adjusted thanks two step motors via pink cranks, blue conrods and violet bar. The latter has spherical joint with the yellow disk, cylindrical joints with two red spheres at its ends. Two green cranks and orange cross create a parallelogram mechanism. The brown disk has two pins that slide in a slot of the orange cross. Four cyan blades are pivoted on the yellow d