Estimation of the underwater radiated noise by ship propeller cavitation using onboard sensor

The use of onboard sensors to estimate the source levels of the underwater radiated noise (URN) of propeller cavitation of a research vessel is evaluated by comparing them to URN data measured by two hydrophones. The onboard sensors consist of accelerometers and pressure transducers mounted on the hull above the propeller. The transfer function to relate hull accelerations to the source level has been determined by measurements in a harbour making use of reciprocity, while the transfer function for the hull pressures is based on analytical formulations. Both approaches give a fair estimate of the source level at high ship speed where the URN is dominated by propeller cavitation noise. The frequency range of the transfer function for the hull accelerometers is limited by the signal-to-noise ratio of its reciprocal measurement.