Underwater noise property of water jet propelled electric boat

The vibration and the noise generated by the water jet electric boats are low compared with those of same sized internal combustion engine boats. However, an objective evaluation of the vibration and the noise from electric boats has not yet been conducted. In this research, an underwater noise from an electric boat and that from an internal combustion engine boat were measured and analyzed. From results of experiments and frequency analysis, maximum noise level of the electric boat was found to be lower than that of internal combustion engine boat. It was also shown that the impeller revolution was the main source of underwater noise from the electric boat.