Abstract: A swimming pool has means for directing a jet of water (J) across the water surface towards a side of the pool to form a counter current (C) against a swimmer, and means for relieving back-pressure at the downstream end of the counter current. The means for relieving back-pressure may comprises a weir (3) over which the jet of water flows. A conduit defines a return flow path (4), and extends towards the upstream end of the jet (J) to facilitate flow of water back towards a pump (1) at the upstream end of the jet. A discrete water level below the water lever in the main body of the pool may be defined by water on the far side of the weir (3). In a variant, a downward transition in water level from the water in the main body of the pool may be provided by water flowing smoothly over the weir (3).

Abstract: A rooftop drag reducing device includes a lower base portion fixedly mounted to the roof of a truck for semi-trailers. An upper portion of the drag reducing device is selectively movable relative to the base portion between a fully extended operating position, and a fully retracted storage position. In the fully retracted position, the upper portion is received within the lower portion such that at least part of the top surface of the lower portion is above the top surface of the upper portion. The design in accordance with the present invention increases the overall stability of the drag reducing device in both the extended and retracted positions, provides enhanced protection for the upper portion in its retracted position fully received within the lower portion, provides greater clearance than is possible with known drag reduction devices, and increases the maximum elevation within the cab or sleeper compartment of the vehicle to which the drag reduction device is mounted.

Abstract: A hat rack adapted to display at various attitudes, a plurality of different peak caps discloses the use of a single longitudinal element carrying a plurality of secondary elements spacially there along, each of the second elements carrying at least two members, preferrably a curved U shaped member at the distal end of the second element, and a vertical U shaped member, relative to the second longitudinal element, about midway there along the said U shaped elements adapted to specifically carry the peak and body of a single cap.