A thin top shell of aerodynamic contour is secured over a jump ski base smooth flow of air over the top of the ski during a jump, without interfering with the on-water performance of the base. The shell has a bulbous tip portion, a first portion of airfoil cross section aligned transversely of the ski...http://www.google.co.uk/patents/US5464358?utm_source=gb-gplus-sharePatent US5464358 - Airfoil jump ski
