Fig. 1. Illustration of the method by which the moment of inertia of a control appendage is calculated. This figure shows an example using the dorsal fin. The vertical z-axis represents the axis of rotation, which runs longitudinally through the center of the dolphin. The horizontal R-axis measures the distance from the axis of rotation. In this example for the model dorsal fin, an isosceles triangular shape is adopted whose height is 0.16 m and base is 0.42 m in length, and is 0.15 m from the axis of rotation. The equations of the canted edges of the dorsal fin are indicated. For our calculations, the area mass density of the control surfaces was taken to be 30 kg m^-2 (F. E. Fish, unpublished data).