Numéro : 2706 - Year : 2016
AQUO project - Researches for solutions to reduce the submarine noise due to the maritime traffic and its impact on the marine fauna - Synthesis and recommendations
Christian AUDOLY, Céline ROUSSET, DCNS Research (Oullioules - France)
Eric BAUDIN, Bureau Veritas (Paris - France)
Thomas FOLEGOT, Quit Oceans (Plouzane - France)
The AQUO Project has been launched in the scope of the European FP7 program, theme “Transport”, in relation with the theme “Oceans of Tomorrow”. With 3 years duration, it ended in December 2015 (see website www.aquo .eu). The final objective is to provide policy makers with practical solutions and recommendations for the mitigation of underwater noise related to ship traffic, with adverse consequences on marine life. To achieve this goal, the AQUO Project adopted a multidisciplinary approach, with a team of specialists of ship vibroacoustics, underwater acoustics and bioacoustics.
After a general presentation of the project, the aim is here to give a synthesis of the recommendations from the AQUO Project. The different types of solutions (at the level of ship design, ship operational parameters or maintenance, and ship traffic control strategies at the level of a maritime area) are evaluated according to three criteria (intrinsic reduction of radiated noise, fuel efficiency, and impact on marine fauna).
Regarding the last point, we have used a computer model to forecast the underwater noise, developed by Quiet-Oceans. That methodology allows identifying the most efficient strategies for the mitigation of the impact on marine fauna of underwater noise related to shipping, as well as the underlying technical solutions. The results of simulations on realistic scenarios show that the strategy consisting in limiting the radiated noise level of the noisiest ships seems to the most efficient. This is consistent with the publication of the new rule note NR614 introduced by Bureau Veritas.
Regarding the reduction of radiated noise at the design stage, the simplified parametric models developed within the AQUO Project were used to assess the efficiency of different noise control measures on a generic commercial ship. It is important to note that the underwater noise radiated by a ship is the combination of noise from propeller (generally cavitating) and machinery noise, the latter coming from different machinery items and different transfer paths. As a consequence, reducing only one of these contributions is in general not sufficient to achieve a significant reduction of the total radiated noise. The simulations show that it is possible to achieve significant reductions (6 dB or more), provided that the different noise sources are treated in balanced manner, for example by combining the use efficient elastic devices for machinery and an improved propeller.