ABSTRACT The purpose of the study is to design and test the devices(de-draggers) that can be incorporated to cylinders to reduce wave forces¡C Two force gauges have been designed to measure simultaneously the x- and z-direction wave forces, especially, for a horizontal cylinder, and the x- and y-direction wave forces, for a vertical cylinder¡C A device with water-drop shape has been fabricated to streamline the flow pattern around the cylinder that can effectively reduce the wake-induced wave force¡C The study will be performed in a wave tank by varying wave conditions and the positions of the cylinder¡CWave forces on the vertical and horizontal cylinders will be measured and compared for the cylinders with and without de-draggers,¡@respectively¡C