Abstract: An arrangement for mounting a cycloidal propeller is disclosed which has elastic support rings and elastic thrust rings. At least the elastic thrust rings are clamped between two frustoconical surfaces which are substantially parallel to each other. One surface is on a ring attached to the propeller base plate and the other is on a ring attached to the propeller foundation. The position of the rings may be changed to adjust the natural frequency of the mounting, for better damping of the forces from the propeller. The elastic support rings are preferably also clamped between parallel frustoconical surfaces. The angle of inclination of all the frustoconical surfaces in relation to the plane of the propeller base plate is between 32.degree.-38.degree..