Analysing the Impact on Underwater Noise of Changes to the Parameters of a Ship’s Machinery

Abstract

A ship moving over the surface of water generates disturbances that are perceived as noise, both in the air and under water. Due to its density, water is an excellent medium for transmitting acoustic waves over long distances.This article describes the impact of the settings of a ship’s machinery on the nature of the generated noise. Our analysis includes the frequency characteristics of the noise generated by the moving ship. Data were obtained using an underwater measurement system, and the measured objects were two ships moving on specific trajectories with certain machinery settings. The acquired data were analysed in the frequency domain to explore the possibilities of the acoustic classification of ships and diagnostics of source mechanisms.

An Acoustic Sea Glider for Deep-Sea Noise Profiling Using an Acoustic Vector Sensor

“…The hydrophone and piezoelectric accelerometer sense the acoustic pressure and particle velocity respectively. The dimensions of the designed AVS are Ø66 × 78 mm with an average density of 1.15 g/cm 3 . Test results indicate that the sensitivity of the hydrophone is −191.5 dB (0 dB re 1 V/μPa), and the sensitivities of the triaxial piezoelectric accelerometer are 2.85 V/g, with the equivalent pressure sensitivities of −179 dB (0 dB re 1 V/μPa at 1 kHz).…”

“…However, further intensive investigation for a better understanding of the ocean needs to be performed and more special sensors are being employed to collect various data. Low-frequency acoustic signals produced by tsunamis, undersea earthquakes, large mammals and artificial vessels are of increasing concern in the area of natural disaster monitoring and marine ecological protection [3], [4]. Moreover, the detection and identification of surface and underwater objects using acoustic sensors are another aspect of great concern in ship navigation [5], [6].…”

Review of Research Results Concerning the Modelling of Shipping Noise

“…On the basis of SL empirical models, Hamson [60], Etter [61], Anon [62], Courtois [63], Colin [64], Audoly [65], Aulanier [66], Jones [67], Folegot [68], Soares [69], Erbe [70], Sertlek [71], and Buszman [72,73], devoted studies to the noise field produced by merchant ships in specific sea areas. Ainslie [35] and Carey [9] introduced the noise mapping of merchants ships in Principles of Sonar Performance Modelling and Ocean Ambient Noise Measurement and Theory, respectively.…”