Abstract: A fin for a surfboard having a base and a tip and wherein the fin includes an integral tunnel which provides a tubular housing; an electric motor and associated propeller attached to the integral tunnel so as to be substantially enclosed therein; wherein the integral tunnel and propeller are both positioned so that there is a blade section above and below the integral tunnel which each have a height which is at least substantially 70% of the diameter of the integral tunnel, and wherein the motor and the propeller are positioned forward of a rear edge of the fin. Also provided is a power source to supply power to the electric motor and associated housing and mounting plate. The arrangement of the motor and propeller are located forward of a rear edge of the fin allows the original feel and maneuverability of a non-powered surfboard to be preserved.

Abstract: A fin for a surfboard having a base and a tip and wherein the fin includes an integral tunnel which provides a tubular housing; an electric motor and associated propeller attached to the integral tunnel so as to be substantially enclosed therein; wherein the integral tunnel and propeller are both positioned so that there is a blade section above and below the integral tunnel which each have a height which is at least substantially 70% of the diameter of the integral tunnel, and wherein the motor and the propeller are positioned forward of a rear edge of the fin. Also provided is a power source to supply power to the electric motor and associated housing and mounting plate. The arrangement of the motor and propeller are located forward of a rear edge of the fin allows the original feel and maneuverability of a non-powered surfboard to be preserved.