Reduction of Underwater Radiated Noise from Ships: New Shipbuilding Challenge. The Vessels "Ramón Margalef" and "Ángeles Alvariño" as Technological References of How to Build Silent Vessels

Abatement of noise radiated by all kinds of vessels, and specially Underwater-Radiated Noise, because of its impacton marine life, has become the most outstanding novelty and the most dificult challenge the shipbuilding industryhas ever faced. Hence, the industry seeks to other new solutions to comply with the new guidelines and requirementsthat have been recently introduced and promoted by the EU, marine institutions, and the scientific community. "isnew topic, already studied and solved by the navies because of their strategic requirements, is now in the limelight andall the different aspects are being studied and discussed among the different players mentioned. In this new trend, theappearance of some class notations with “different limits”, assertions such as that the “propeller” is the major noise source,and the absence of consensus among the biological community about what should be the limits (for not affecting marine fauna), it is difficult to define the technological steps that should be followed. Until a consistent agreement is reached, the shipbuilding industry and the naval engineers will be “fighting against a ghost”. Within this “confusing scenario”, this paper is a clear example of how the Spanish shipbuilding industry is moving ahead to reduce the impact of new ships. The dynamic and acoustic design, developed by the authors, of the fishing research vessels “Ramón Margalef” and “Ángeles Alvariño” for the Oceanographic Spanish Institute and the experimental results obtained, in full compliance with ICES N°209 Underwater-Radiated Noise requirements, makes them reference vessels for the construction of “Silent Vessels”.