Underwater Radiated Noise Rating of Ships

View Report

February 2025 — Canada

Client: Transport Canada

This technical memo presents a method for rating ships according to measurements of their underwater radiated noise (URN). The overall goal is to assign URN grades to ships. The rating method is intended to be applied by agencies and organizations responsible for managing underwater ship noise. Noise criteria are defined for four URN grades (A to D), and methods for accurately measuring ship radiated noise levels and evaluating measurements against grading criteria are provided here. The grade limits and measurement methods can also be useful for ship classification societies for defining their own quiet ship notations.

The recommendations are based on research on ship underwater noise characterization projects that has been supported by Transport Canada and the Port of Vancouver’s Enhancing Cetacean and Habitat Observation (ECHO) Program, and from research performed by many organizations worldwide to develop international standards for ship noise measurement.