Wave Direction Measurement by a Single Wave Follower Buoy

This paper describes a system for measuring the direction of ocean wave propagation, as well as wave height and period. The system employs a conventional wave follower buoy, modified so as to provide compass, pitch and roll signals in addition to the vertical component of buoy acceleration. The modifications are indicated in the paper, and the buoy was tested in two sea state conditions in Narragansett Bay. The pitch, roll, compass, and heave acceleration signals were all processed on the computer in the laboratory to provide a variety of results. One test condition was ideal in that the wind and wave conditions were changing steadily throughout the data recording process. The second test was exactly opposite, with small waves and a consistent wind direction. The results presented in the paper include the wave height power spectral density, a polar tilt histogram for the buoy motion, and a family of polar plots of the average tilt angle in each sector of azimuth of the buoy pitch/roll.