2019 Volume 4 Issue 1 Pages 29-38
Hydrogen fuel-cells produced using surplus electric power and industrial by-products have desired energy efficiency and do not produce discharges containing atmospheric toxic substances such as carbon dioxide and NOx. The development of a vehicle and a vessel that can transport hydrogen fuel cells is considered at present. In the case of the vessel, a decrease in the underwater noise is an additional advantage. In this study, we considered the differences between the amplitude and frequency characteristics of underwater noise of a fuel-cell, small diesel, and aquaculture working vessels. Recordings were acquired based on four speed condition of 4, 8, 10, and 14 knots. The radiated underwater noise spectrum levels (RNL, dB re 1μPa/√Hz at 1 m) were calculated from the recording sounds. The RNLs of the fuel-cell vessel at every speed were lower than those of the other vessels and less than 300 Hz of the sound frequency. In contrast, the RNL of the aquaculture working vessel exhibited some peaks for low frequencies less than 300 Hz, and it was thought that engine noise had a considerable influence on this behavior.