Abstract: A leisure boat is provided in a round form having a diameter of about 1 to 2 meters, and includes propeller means provided at a position closer to its bow from the center of the boat and the bow and having a mechanism for changing its driving direction and sensor means provided on the outside of the boat for sensing external force. The sensor means is so connected to the propeller means that when the boat comes in contact or collision with another boat, etc., the sensor means detects the resulting external force to transmit it to the propeller means, thereby changing its driving direction.

Abstract: A roller element for a slide comprising an outer cylinder, an inner pipe and connector members for making connections therebetween all integrally formed of a material having a suitable elasticity, wear resistance, weather resistance, etc. wherein the outer cylinder has a thickness sufficient to make it deformable, and stopper slightly shorter than the space formed between the outer cylinder and the inner pipe are provided to limit the amount of deformation of the outer cylinder, alternatively ribs for connector members which are connected to the outer cylinder and inner pipe on a reduced-diameter side of the outer cylinder, and connected to the inner pipe alone on an increased-diameter side of the outer cylinder to form a gap of about 2-3 mm between the outer edge of the inner pipe and the inner face of the outer cylinder.

Abstract: A water slider lane includes a sliding surface the effective portion of which has a width larger than the diameter of a sliding boat. The sliding surface is bent or tilted down toward one side, thereby moving a sliding boat toward a turning zone. A region of the sliding surface, at which the sliding boat approaches the turning zone, is tilted up to form an upward slope, and the upward slope is connected at its upper edge and through a bend to a side wall of the lane, whereby the sliding boat goes up the upward slope to such a degree that its upper portion goes slightly beyond the upper edge of the upward slope. When the sliding surface has its effective portion's width smaller than the diameter of a sliding boat, a step in the form of a ridge and others may be provided on the sliding surface.

Abstract: A bearing case for a roller slide comprises a casing, an arm, a stopper formed on the casing and a pawl retainer formed around the outer edge of an end of the arm, which are all formed of a tough material by integral molding. The casing for receiving a bearing comprises a drum, an inner lid and an outer lid and has a depth virtually equal to the thickness of the bearing and an inner diameter virtually equal to the outer diameter of the bearing, and the arm has an outer diameter virtually equal to the diameter of a hole in which the bearing is built.

Abstract: A leisure boat is provided in a round form having a diameter of about 1 to 2 meters, and includes propeller means provided at a position closer to its bow from the center of the boat and the bow and having a mechanism for changing its driving direction and sensor means provided on the outside of the boat for sensing external force. The sensor means is so connected to the propeller means that when the boat comes in contact or collision with another boat, etc., the sensor means detects the resulting external force to transmit it to the propeller means, thereby changing its driving direction.

Abstract: The present invention provides a water slider used with a round or substantially round tobogganing boat designed to be displaced into contact with one side of a slide lane in the course of toboganning. A side wall of the slide lane comes into contact with the boat and has a nearly vertical portion brought in contact with a side or side edge of the boat, thereby increasing the friction between the side wall and the boat to substantially or completely eliminate any relative slippage therebetween. The slide lane may be provided on one side with a slight dent.