Public Reports & Articles
Recommended Procedures for Measuring Underwater Radiated Noise Emissions of Ships
September 2023 — Canada
Client: Vancouver Fraser Port Authority and Transport Canada
JASCO has provided technical expertise to a collaborative project aimed at developing guidance for ship certification societies wishing to issue quiet ship notations. The guidance document was developed through a series of workshops attended by representatives from the following Classification Societies: American Bureau of Shipping, Bureau Veritas, China Classification Society, DNV, Korean Register, Lloyd’s Register, Registro Italiano Navale. Also in attendance were members of the International Association of Classification Societies and the International Organisation for Standardization (ISO). The expertise and contributions of these representatives and members were instrumental for defining practical, consistent, and technically-sound methods for measuring and reporting underwater radiated noise from ships, suitable for assessing quiet notations.
An accompanying spreadsheet provides quartile levels of ship RNL measurements from VFPA’s ECHO Program database for several ship categories, that can be used to establish reasonable noise limits. The spreadsheet includes scaling parameters to account for different values of vessel speed through water.
Acoustic Footprint of Bottom Trawling in the Adriatic Sea
September 2023 — Albania
Client: General Fisheries Commission for the Mediterranean
JASCO Applied Sciences (Deutschland) GmbH collaborated with the General Fisheries Commission for the Mediterranean to perform a Sound Source Characterisation (SSC) study of representative fishing activity in the Adriatic Sea off the coast of Durrës, Albania. The study was funded by Global Environmental Facility and took place in August 2023; it consisted of recording underwater sound radiated by a bottom trawler vessel before and during typical fishing operations. The aim of the measurements was to increase the scarce publicly available data on sound emissions from fishing vessels, and to enable more accurate modelling of noise impacts from fishing activities involving single or multiple boats near ecologically sensitive locations. To that end, from the analysis of the recorded data, the spectral source level of the vessel was to be computed so it could be used to improve the realism and accuracy of future modelling. In 2021 JASCO had performed such a numerical modelling study of fishing operations in the Adriatic at the Pomo/Jabuka Pit Fisheries Restricted Area, which had evidenced the scarcity of available sound levels data for fishing vessels engaged in their work.