A rooster tail is a term used in fluid dynamics, automotive gear shifting, and meteorology. In fluid dynamics, it lies directly in the wake of an object traveling within a fluid, and is accompanied by a vertical protrusion. If it occurs in a river, boaters upstream steer clear of their appearance. The degree of their formation can indicate the efficiency of a boat's hull design. The magnitude of these features in a boat increases with speed, while the relationship is inversely proportional for airplanes.

More Info: www.desperatesailors.com