Underwater noise

The International Maritime Organization’s (IMO’s) Guidelines on Underwater Radiated Noise were reviewed in 2023. The aim of this review was to increase uptake and understanding of how URN impacts other environmental elements such as Energy Efficiency and its further impact on Biofouling.

A full report of the updated 2023 Guidelines can be found here. The main elements include an example format for a Noise Management Plan and possible approaches discussed to establish baseline measurements, URN Targets and predictions where applicable in terms of URN Management. The Guidelines aim to advise and provide a reference for stakeholders to establish their ship-specific Noise management plans and the establishment of targets and actions associated.

Through the development of the revised Guidelines, the positive synergy URN has with energy efficiency was a recurring theme. This was culminated in a workshop hosted by the IMO on the relationship between these topics.  This relationship is mutually positive in the majority of actions with only optimizing the propeller blade area and running controllable pitch propellers at slower speeds having negative impacts on the relationship due to the increased cavitation.

The profile of this topic is growing significantly with a place on the MEPC agenda, the EMSA EMTER report and more recently an AMSA circular.

INTERTANKO remain active in the development and next steps of these guidelines through its Environmental Committee, participating in Tripartite Working Groups, Correspondence Groups and Working Groups at the IMO during the 3-year Experience Building Phase (additional 2 years optional) and monitoring regional/national developments.

Click on the following areas for further details:

• Report from IMO SDC 10
• SDC9: Underwater Radiated Noise (URN)