Numéro : 2308 - Year : 1999

Acoustic discretion improvement of a merchant ship, a practical example: LA THALASSA

M. Hervé QUERE, DCN/Brest
M. Olivier LEFORT, IFREMER

The Fishery Research Vessel Thalassa has been designed to reach a low level of acoustically radiated noise. After delivery, an inventory of fixtures has been conducted by running the ship through a field of sea-bottom hydrophones. Fifteen equipments have been identified as a potential cause of acoustic pollution between 10 and 30 Hz.

DCN I Brest has given an expert opinion on these machines and proposed a number of modifications, which have been realised. Three significant examples of modifications are shown : ventilators of the electric propulsion, stabilised courant plants, sea-water pumps. Only one part of the modifications show a gain when conducting closed field measurements. The reasons are analysed.

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