Generally, both horizontal and vertical boom motion must be used to suppress the load sway caused by horizontal boom motion of a rotary crane. However, it would be less energy intensive and also safer if a control scheme could be developed that only used horizontal boom motion, i.e., without the need for any vertical boom motion. In addition, if load sway can be suppressed without measuring it, reduction in sensor cost can be achieved. Furthermore, employing simple velocity trajectory patterns such as trapezoidal and S-curve patterns, which are widely used in industrial automation systems, may provide cost effective controller implementation. This study presents a simple S-curve trajectory generation method for rotary crane motion that can suppress residual load sway using only horizontal boom motion without load sway sensing. Numerical simulations and experimental results demonstrate the effectiveness of the proposed method.