The MARS Project: Concrete results to better understand the issue of underwater noise generated by vessels

Since 2021, an acoustic monitoring station has been deployed every spring in the Laurentian Channel, off the Rimouski coast. Four antennae, each equipped with three hydrophones, are installed at a depth of 350 metres (1,148 feet) near the St. Lawrence River’s navigation channel to measure the acoustic signature of vessels according to international standards.

An inter-institutional research team of approximately 15 people was set up to ensure the project was carried out. This is coordinated by the Institute de science de la mer (ISMER), which is the Institute of Marine Sciences at the Université du Québec à Rimouski (UQAR), and the Innovation Maritime research centre (also in Rimouski), with the support of MTE Instruments and OpDAQ Systems.

The project’s initial phase, led primarily by ISMER, focused on measuring the acoustic signature of significant portion of the St. Lawrence fleet. A database of 2,500 acoustic signatures was established, by collecting as opportunities arose the signatures from vessels using the Seaway. Additionally, through the collaboration of four partnering ship owners – Desgagnés, Canada Steamship Lines, Fednav, and Algoma – 250 vessels followed a predetermined protocol that allowed for the measurement of their acoustic signature according to the ANSI/ASA S12/64-2009 standard, and were also made the subject of individual reports specifically for the ship owners. These results allow the ship owners to quantify the noise contribution of each of their vessels within their fleet and in relation to the rest of the St. Lawrence fleet.

A processing chain has been set up to produce acoustic signatures in an automatic, documented and repeatable manner. The database thus created makes it possible to support the efforts of maritime stakeholders towards quieter navigation, to provide quantitative information on the St. Lawrence fleet to decision-making bodies, and to support scientific research towards understanding the mitigation of noise impacts on the marine environment.

This approach, through vibration diagnostics, aimed to identify the sources of noise aboard a vessel and to assess their respective contributions to radiated noise in the marine environment. Eighteen (18) missions of this type were carried out as part of the project. This aspect of the project required the development of customized equipment for data acquisition, capable of collecting continuous vibration data and studying the response of the structure to vibrations.

Sound diagnostics carried out simultaneously with acoustic measurements in the MARS Station, make it possible to understand radiated noise, from its point of origin on the vessel to its transmission to the marine environment. Diagnostic reports are prepared and provided to ship owners. These reports identify key noise sources and their contributions to each vessel’s acoustic signature, enabling ship owners to take targeted action to reduce their noise footprint. One of the project’s innovative aspects derived from the internal vibration measurements is the detection of cavitation, which is a major generator of underwater noise.

Cavitation, which is caused by the formation of steam bubbles around the propellers, is a major issue to address to reduce the impact of commercial navigation. Its early detection, thanks to non-intrusive monitoring systems, will ultimately facilitate an intervention to reduce its effects, for example, by adjusting navigational parameters in ecologically sensitive areas or by carrying out propeller maintenance.

Collaborations with European teams as part of the PIAQUO (Practical Implementation of Achieve QUieter Oceans) Project were established and made it possible to exchange the respective results of the different projects.

Over the past three years, the MARS team has made significant advances in measuring and comprehending underwater noise generated by vessels. It is now important to continue the work to enrich the acoustic signature base, increase data collection aboard vessels and, above all, test mitigation measures.

Some solutions are already in development and will be tested. More specifically, testing will be done on a hull coating that has the potential to reduce radiated noise in the marine environment, and on shock absorbers that cut off the transmission of vibrations to the hull, as well as resonators that attenuate certain vibrational frequencies that are specifically identified as problematic. Another initiative relies on the deployment of a network of sensors placed aboard vessels to estimate in real time the nose radiated from the vessels, transmitting this information to the wheelhouse so that captains modulate their speed according to the noise generated by the vessel and based on areas of ecological interest. Although significant progress has been made in recent years, challenges remain in suggesting effective noise mitigation solutions that are well suited to the operation context of ship owners.

The MARS Project benefitted from financial support from Transport Canada, the Ministère de l’Économie, de l’Innovation et de l’Énergie du Québec (Quebec’s Ministry of Economy, Innovation and Energy), as well as contributions from MTE Instruments, OpDAQ Systems, and several Green Marine certified ship owners (Desgagnés, Canada Steamship Lines, Fednav, and Algoma) and the Société de développement économique du Saint-Laurent (SODES, which focuses on the St. Lawrence region’s economic development). The project’s promoters are currently seeking to obtain new financial support to be able to continue the work carried out over the past three years.

About the authors

He aims to promote collegial research in the maritime sector and develop structuring research partnerships. He is also a doctoral candidate in Mechanical Engineering, jointly between l’École nationale supérieure Mines-Télécom Lille-Douai and l’École de technologie supérieure in the development of additive manufacturing processes for metal parts.

His research focuses on underwater soundscapes as a means of providing information on marine fauna, meteorological events, and anthropogenic pressures. He leads the acoustic observation activity of the MARS Project, and the team of six people at ISMER responsible for the operation of the acoustic monitoring station, and the collection and scientific analysis of data.