The need for the development of the guide fin design that will be used in vertical double shaft wind turbines, the development of the directional tail fins are used to increase the efficiency of the wind turbine. By using a ratio of 1.4 and the area being scaled to 0.042 m2. The purpose of this research is to make a prototype scale model of the fin, make the fin mount, and determine the design of the guiding tail fin based on its damping effect. The testing process is carried out in a wind tunnel with a test speed of 1 m/s -5 m/s with test angles of 5˚,10˚,15˚,20˚,25˚, and 30. The testing process is performed using a video recording with slow-motion mode, which will be tracked on the tracker software, later producing a graph to determine the tail fin with the best attenuation. From the test results, it is found that the 1A Single fin is the best fin based on its damping effect with an average number of waves at each speed and also an angle of release of 1.1 waves, an average amplitude of 0.014591609 m, and a damping time of 16.16321429 s.