The Port and Harbour Research Institute has built a serpent-type wave-maker which generates the directional random waves similar to real seas and is installed in the experimental basin newly constructed for deep water offshore structures.
　The present paper describes the characteristics of the wave-maker, the control system and the wave generation by the wave-maker. The wave-maker is a movable serpent-type one whose individual unit has a wave paddle of 0.8 m wide. The wave-maker is controlled through the micro-computer system, which consists of two systems of D/A converters for the wave signal transmission, digital input and output systems, and two remote controllers. The differences among the wave paddle motions in the same signal are small enough to be satisfactory. The time interval of the D/A conversion should be about 0.025s in order to assure the smooth motions of the wave paddles.