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

Publio Beltrán Palomo

doi:10.25043/19098642.102

Abstract

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”.

Highlights

As previously mentioned and within the framework of the Green Policy of the EC and maritime institutions like IMO and ILO, all the targets de ned focus on combating and reducing the current “environmental impact” of all types of vessels that make up the current European Fleet
A common conclusion reached from these projects [9] is that the Noise & Vibration (N&V)-Full Signature (N&V-FS) of the vessel is required to assess properly its environmental impact. is indicator is made up by the N&V on board, Noise Radiated to Harbour (NRH), and the Underwater Radiated Noise (URN), being the URN and NRH the most outstanding novelty and, in the case of URN, the newest and greatest challenge to be faced
Very few data from “civilian vessels” regarding this aspect is available apart from some interesting results of URN measurements in the literature [1, 12, 13, 14]. ese publications are very interesting because several URN signatures of various commercial vessels, are presented. ese URN levels come with detailed descriptions of the measurement conditions and of the ships’ characteristics, which allows data analysis. is lack of URN data is because no URN requirements are available in the vessel contract speci cation. e only exceptions are the shing research vessels (FRV) because of their performance requirements

Summary

Introduction

As previously mentioned and within the framework of the Green Policy of the EC and maritime institutions like IMO and ILO, all the targets de ned focus on combating and reducing the current “environmental impact” of all types of vessels that make up the current European Fleet. Based on these experimental data, the message to the shipbuilding industry is clear: abatement of the URN signature of “new vessels” will require preventive control of the sources and actions focused on reducing vibration energy transmission from main mechanical sources, like main machinery, to the hull. Ese results are not a question of luck; they are based on solid pillars: the rst one is the high level of sensitization shown by the owner (IEO), who de ned a technical speci cation that included speci c requirements to guarantee: comfort and good working conditions of the crew and scientists, reduction of the vessel’s environmental impact, and, the high e ciency of the scienti c echo-sounders on board. The excellent experimental results obtained enable validating and consolidating the “Noise & Vibration Integrated Management” methodology the author has been applying for over 36 years

Length overall

BUREAU VERITAS vessels

Findings

Methodology