To rationalize the time for repairing and adjusting a machine by calculating a contribution amount of a main sound source machine to underwater sound based on calculation results of frequency components of an underwater sound digital signals and each vibration digital signal.
An underwater sound detector 6 and a plurality of vibration detectors 8 detects underwater emitted noise and vibration by a main sound source machine respectively, and an A/D-converter 10 digitally converts them for feeding to a calculation processing part 12. Then a spectrum calculation part 15 fast Fourier transforms both signals to calculate spectral signals of auto power of each signal and cross powder of each vibration, and a coherent output power(COP) calculation part 17 calculates COP of each sound source machine vibration for underwater sound. An auto power spectrum of the underwater sound among them and that of a normal underwater sound are displayed on a display device 19 to specify a frequency where current underwater sound frequency increases from normal time. Then in each machine of specific frequency, a machine with present COP > normal COP is specified as a cause for an increase of the underwater sound, and it is repaired and adjusted.
HONDA IWAO
ARAKI KAZUTOSHI
HAYASHI YOICHIRO
KANDA YUICHI
