Report of the Shipping Session
De Jong, C.1*, Baudin, E.2*, Yubero, R.3*, Andersson, C.4*, Gervaise, C.5*, Lajaunie, M.6*,
Andersson, M.7*, Gaggero, T.8*, Gaudel, R.9*, Daoud, W.10*, Lafeber, F.-H.11*
1 TNO, The Netherlands
2 Bureau Veritas Solutions Marine & Offshore, France
3 TSI, Spain
4 IVL Swedish Environmental Research Institute, Sweden
5 Chorus, France
6 Service Hydrographique et Oceanographique de la Marine (SHOM), France
7 Swedish Defence Research Agency, Sweden
8 University of Genova, Italy
9 Damen Research, Development & Innovation , The Netherlands
10 Ponant, France
11 Maritime Research Institute Netherlands (MARIN) – The Netherlands
* Session Chairs and Corresponding Authors; E-mail: christ.dejong@tno.nl – eric.baudin@bureauveritas.com – roberto.yubero@tsisl.es – carl.andersson@ivl.se – cedric.gervaise@chorusacoustics.com – myriam.lajaunie@shom.fr – mathias.andersson@foi.se – tomaso.gaggero@unige.it – renaud.gaudel@damen.com – wdaoud@ponant.com – F.Lafeber@marin.nl
This report can be referenced as: De Jong, C., Baudin, E., Yubero, R., Andersson, C., Gervaise, C., Lajaunie, M., Andersson, M., Gaggero, T., Gaudel, R., Daoud, W., Lafeber, F.-H. (2023). Report of the Shipping Session, OCEANOISE2023, Vilanova i la Geltrú, Barcelona, Spain, 22-26 May. Retrieved from https://2023.oceanoise.com
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Introduction
In the shipping session of OCEANOISE 2017 the variety of presentations highlighted that the key shipping stakeholders have progressed significantly in the consideration of the complex issues linked to understanding, quantifying, and further reducing the underwater radiated noise (URN) from ships. The incentives set-up by the Port of Vancouver in early 2017 catalyzed the early movers’ efforts. Several key methodological outputs from EU projects such as BIAS, SONIC and AQUO, as well as dedicated measurement studies, confirmed the need of moving on with the standardization of ship URN measurements in deep and shallow waters.
Since then, the progress has continued and the presentations at OCEANOISE2023 demonstrated that many of the remaining open issues identified in the session report from 2017 have been and are being addressed. From the ship design and marine engineering side, UNIGE, Ponant and MARIN presented technical solutions for reducing ship radiated noise, nonetheless insisting on the need of validation data to be able to scale-up rapidly and in a cost-efficient way. It was concluded that more data could be gathered from opportunistic measurements of underwater radiated noise from passing ships, aiming at collecting large number of ship signatures, but that gathering consistent data requires availability of an internationally agreed measurement standard. Speakers underlined the need of quantifying the risks and benefits of operational solutions such as speed reduction as well as clarifying what relevant indicators would help quantifying the effects of ship noise on marine life.
It is clear that the view of the Shipping session of OCEANOISE is in line with the commitments of not only addressing the reduction of URN but to do so while cautiously considering the potential consequences on the ship efficiency and so on its greenhouse gas (GHG) emissions. At the international level the GHG emissions management is indeed the top 1 priority and related IMO regulation is on track and short term measures are in force since January 2023.
Session summary
Reducing GHG emissions is the major target of the shipping energy transition. Some solutions are likely to also bring co-benefits to the noise radiated underwater by ships. That has been presented by IVL for the case of an electric hybridization of a ferry in Sweden. Damen studied a newbuilt ferry with full electric propulsion case it appears that the significant peak levels in the URN due to machinery (gear noise from azimuth thrusters and electric motor related frequencies) can be reduced, while unmanaged propeller cavitation noise will remain and thus still incur significant URN levels. A balanced approach of URN reduction is essential as GHG reduction solutions might not always lead to URN ones.
On a more global scale, the MARS project, in progress in St Lawrence, Canada is not only conducting high-fidelity URN measurements using a 2 gate-fixed station but has also developed a time (and so cost) effective solution to run on-board vibration measurements, aiming at validating transfer functions with outboard measurements. SHOM has brought an innovative statistical approach to analyse the measurements performed thanks to a multiple array set-up composed with 12 moorings with 2 and up to 4 hydrophones.
FOI highlighted the consequences on URN of a relocation of the shipping lanes in the Kattegat. This showed an application of marine spatial planning that did not lead to an overall reduction of URN and it raised as well the need of having a reliable and robust method for long-term measurements to distinguish geophony from anthrophony.
On the design stage, UNIGE emphasized the progress made in the last 6 years on the methodologies and tools to predict a given propeller design URN and presented a possible technique for real-time URN monitoring system from accelerometers to inform the crew and help in the decision making. Validation of a passenger ship within the framework of PIAQUO project is in progress. MARIN has shared the various technical solutions studied within the framework of SATURN project and the corresponding results out of the numerical simulations (e.g. propeller optimization under efficiency + URN targets) and model tests (e.g. hull masker and Prairie system to respectively reduce the machinery noise and the propeller cavitation noise)
With regards to ship measurements, TSI has addressed within the framework of SATURN, through extensive set of URN measurements, the directivity and averaging aspects of single ship URN measurements. IVL also shared results regarding ship measurements and the influence on directivity, showing how different procedures for time-averaging measured decidecade band levels influence the calculated source levels in opportunistic measurements.
The consideration of the luxury cruise ship owner PONANT for the underwater noise topic is not only revealed through the assessment of their ship’s signature but also in their participation to several initiatives aiming at bringing more insights on the link between marine fauna and URN.
From these insightful talks, we have converged towards confirming the need of carry on working on standardization. It has been as well a good opportunity to highlight all the significant steps achieved since 2017 and so, to pledge for a massive use of the available standards when measuring URN from ships.
Technical solutions and case studies have raised much interest: how much would URN change for a 1% gain in efficiency through optimizing a propeller? Are controllable pitch propellers (CPPs) a viable solution? Is there a scaling effect in the URN reduction associated with the bubble size distribution of a masker system?
Should we conclude here the debates: engineers are ready enough to move on with testing various solutions with regards to their URN reduction and implementing the most promising ones. Nevertheless, the massive engagement of ship owners is the only real leverage to be able to collect more cases, more data. In the meantime, opportunistic measurements are still identified as the best option to build-up an insightful database as it has been done in Vancouver thanks to the ECHO programme.