Abstract: The invention relates to a linear propeller device capable of use for propulsion of amphibious vehicles or for liquid pumping, the device having an endless outer surface having a substantially uniform width and being arranged to be movable along a predetermined path substantially perpendicular to the width, at least one row of spaced blades extending along the length of the outer surface and projecting outwardly therefrom, and each blade being disposed at a predetermined acute angle to the path, whereby, upon movement of the outer surface along the path with a portion of the row of blades submerged in a liquid, the blades induce relatively undisturbed flow of the liquid from one side of the blades to the other side of blades through the spaces between the blades and thereby produce thrust for propelling a craft in water or pumping liquids.