It is an object of the subject matter to disclose an aquatic apparatus comprising a fin connected to a bottom of the an aquatic device; a flap connected to the fin, wherein the flap is connected at a leading end of the flap to the fin by one or more connectors, wherein the connectors enable the flap to rotate according to water current; one or more cables connected to a trailing end of the flap, wherein each cable of the one or more cables connects the flap the fin; said one or more cables comprising a predetermined length to enable the flap to open and close.