抄録
The method of speed trial analysis which evaluates the effects of encountered waves and steering as well as wind and current is proposed by SR-208 Panel of the Shipbuilding Research Association of Japan. In this paper, a new practical wave height measurement system developed for the speed trial analysis is introduced. According to the Guidelines of Standardization Speed Trial Analysis prepared by SR-208 Panel, significant wave height and mean period of waves for seas and swell are necessary. Although these data are usually based on visual observation, this system makes it possible to evaluate the wave height and mean period with reliability and to introduce a sort of objectivity. The wave height meter consists of a buoy and a pressure sensor, and the data measured by the sensor is transimitted through an electric wire to the analysis system on the fishing boat chartered for a trial. The analog data transmitted is digitalized by the AD converter for the first, and spectral analysis is made by the personal computer on the boat, which gives the information about the wave height and period of the total wave for seas and swell. The significant wave height and mean period of waves for seas can be obtained from the total wave data by introducing the relative information such as the wave height ratio and the wave length ratio of seas to swell. These relative data are based on visual observation. The significant wave height and mean priod of waves for swell can be also obtained in the same way. The use of this measurement system for the speed trial analysis was admitted for the recent trials of LNG carriers. Some applied examples are also introduced in the paper, with the more detailed explanation of the system.
