Abstract: The invention concerns a flood protection for protecting a back area against rising water level from a front area, the flood protection operating between a bottom and a water surface, including at least one barrier element with a longitudinal direction and a height direction, the longitudinal direction during operation extending substantially transversely of an area, e.g. a stream, a fjord, a river or an estuary, and the height direction during operation extending from the bottom of an area, e.g. a stream, a fjord, a river or an estuary, and up, where the at least one barrier element during operation interacts with a base arranged at the bottom of the actual area. The invention also concerns a method for operating such a flood protection.

Abstract: The invention concerns a flood protection for protecting a back area against rising water level from a front area, the flood protection operating between a bottom and a water surface, including at least one barrier element with a longitudinal direction and a height direction, the longitudinal direction during operation extending substantially transversely of an area, e.g. a stream, a fjord, a river or an estuary, and the height direction during operation extending from the bottom of an area, e.g. a stream, a fjord, a river or an estuary, and up, where the at least one barrier element during operation interacts with a base arranged at the bottom of the actual area. The invention also concerns a method for operating such a flood protection.

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.