A comparison of quiet ship certifications with the Enhancing Cetacean Habitat Observation (ECHO) ship noise database

Abstract

Measurements from the large ship noise database acquired by the Vancouver Fraser Port Authority’s Enhancing Cetacean Habitat Observation (ECHO) program were used to assess the conservativeness of five vessel noise certification societies. A multi-variate linear regression analysis of the database was used to scale ECHO measurements to a common reference vessel type for each of 6 categories: tug, tanker, bulker, container ship, vehicle carrier, cruise ship. The purpose of scaling the ECHO measurements was to create a modified dataset to compare with existing vessel noise certification society noise thresholds. The conservativeness of the certification society thresholds was found to vary with vessel category. The general findings are that the society limits are conservative for faster categories (e.g., container ship) but not for slower vessels such as tankers, and certification systems using monopole source level (MSL) had better matches with measurement data than the approaches using radiated noise level (RNL). None of the certification societies accounts for differences of vessels within a vessel category. Therefore, small ships are currently evaluated against the same threshold criteria as large ships. The scaling system developed here using the ECHO dataset could be used to scale measurements (or thresholds) to account for different vessel sizes and operating conditions. This research was funded by Transport Canada.Measurements from the large ship noise database acquired by the Vancouver Fraser Port Authority’s Enhancing Cetacean Habitat Observation (ECHO) program were used to assess the conservativeness of five vessel noise certification societies. A multi-variate linear regression analysis of the database was used to scale ECHO measurements to a common reference vessel type for each of 6 categories: tug, tanker, bulker, container ship, vehicle carrier, cruise ship. The purpose of scaling the ECHO measurements was to create a modified dataset to compare with existing vessel noise certification society noise thresholds. The conservativeness of the certification society thresholds was found to vary with vessel category. The general findings are that the society limits are conservative for faster categories (e.g., container ship) but not for slower vessels such as tankers, and certification systems using monopole source level (MSL) had better matches with measurement data than the approaches using radiated noise level...