Assessment of the underwater noise levels from a fishing vessel using passive acoustic monitoring and structure hull vibration

Authors

  • Khaled Helal PhD candidate, Memorial University
  • Lorenzo Moro

Abstract

Human activities, such as shipping, fishing, and deep-sea mining, are significant sources of acoustic pollution,resulting in an alteration of the ocean soundscape and consequent endangering of the marine ecosystems.Several publications highlight ships’ contribution to underwater noise pollution and the consistentgrowth in the global vessel fleet over the last few decades. Strategies to mitigate this environmental threatrequire the characterization of ships as acoustic sources and, therefore, underwater radiated noise measurementprocedures (URN). Accurate measurements of underwater source levels depend on environmentaland technical parameters, such as vessels’ speed, water depth, and sound speed profile. Theseparameters, along with the distance between the sources and the hydrophones, impact the uncertainty inestimating the radiated noise levels.

This paper presents a study on the measurement uncertainties when assessing underwater radiated noisefrom ships. We used a fishing vessel as a case study and performed sea trials in August and December2021. Accelerometers were mounted on the vessel structure to measure structure-borne noise from thediesel engine, while an array of hydrophones was deployed to measure the vessel’s underwater radiatednoise. Each trial was performed at different speeds and ranges. The structure-borne noise measurementswere used to understand the contribution of the engine to the overall URN at different operation conditions.Finally, monopole levels were estimated for each source as well as for the overall radiated noise by implementingtwo different methods.

Results show that the engine contribution to the overall URN is significant for this type of vessel. In addition,the depth of the source and sound speed profile are critical parameters for an accurate estimation of themonopole source, while the underwater radiated noise is also affected by the range.

Additional Files

Published

2022-08-09

How to Cite

1.
Helal K, Moro L. Assessment of the underwater noise levels from a fishing vessel using passive acoustic monitoring and structure hull vibration. Canadian Acoustics [Internet]. 2022 Aug. 9 [cited 2024 Nov. 4];50(3):110-1. Available from: https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3876

Issue

Section

Proceedings of the Acoustics Week in Canada