Abstract: A propeller (1) for commercial vessels as well as sailing ships with an auxiliary engine, having a hub (2) and at least two propeller blades (1) which are pivotally mounted in the hub (2). The blades (1) are pivotable between unfolded operating positions and at least one passive position in which the shaft does not rotate, and the blades extend axially rearwardly in extension of the hub (2). The blades (1) are moveover adapted to pass each other in said passive position. In the passive position, the blades (1) extend axially away from the hub (2) with the same side edge (15) of the two side edges (14, 15) of the blades facing each other. The propeller can hereby have either the front edge (14) of the blades or the rear edge (15) of the blades as the leading one so that the propeller can operate in ordinary gear or in "low gear" thereby enabling optimal efficiency in several operating situations. Further, the propeller offers minimal water resistance in the passive position.

Abstract: A propeller in particular for a ship has blades each of which is pivotally arranged in the hub of the propeller so that the blade is capable of pivoting to and fro in an axial plane between forward and rearward positions. The blades are constructed such that each of the blade profiles formed as the intersecting face between a cylinder face coaxial with a propeller and a blade, is symmetrical in a position between forward and rearward positions which are determined by fixed stops in the hub and/or the simultaneous actions of the centrifugal force and the hydrodynamic pressure on the blade at a predetermined speed of rotation. This imparts a high efficiency and a quiet and steady operation to the propeller, when the ship navigates forwardly and rearwardly.