摘要 |
<p>An aquatic surface projectile (10) for recreation and/or exercise use either individually or in team play. The aquatic device is manually propelled by throwing so as to skim along the surface of a body of water in a smooth skimming action and not by skipping or tumbling. The lower surface (12a, 12b) of the projectile is preferably an inverted frusto-conical shape, with shape variables including the inner radius (RI), the outer radius (RO), and the altitude angle (a). The lower surface shape produces a positive, nose-up attitude and hydrodynamic lift to reduce drag for enhancing range and velocity of the projectile while providing smooth skimming on the water surface. In addition to the projectile shape considerations, the projectile is also made relatively lightweight to provide enhanced skimming action and to prevent undesired skipping and tumbling of the projectile. The altitude angle, radius ratio (RI/RO) and the weight-per-plan area ratio are interrelated according to specified formulas.</p> |