1971 Volume 46 Pages 209-213
As to the nooring and maneuvering of a ship in harbour, the ship's motions induced by the sea waves in harbour were calculated and discussed from the view point of the statistical analysis of random process. Concerning the measurement of wave heights in Hakodate harbour, the wave heights were measured, simultanously, by the use of a step type wave measuring pole at 4 points of observation stations which are shown in Fig.1. On the records of wave heights of these stations, the power spectra were calculated and are shown in Fig.2. From the wave spectra in Fig.2, it is found that the breakwaters of the harbour have a characteristic as a high pass filter for sea waves. As the example case of a ship's motion in harbour, the author calculated the ship's motion spectra by the relation of epuations (1) and (2) on the coupled heaving motion. The result of the calcualtion in shown in Fig.4. Based on the calculated motion spectrum, the extreme value of motion was calculated and discussed.