Insights from the IMO 2025 Workshop on the Relationship Between Ship Energy Efficiency and Underwater Radiated Noise
Ocean Sonics’ Mark Wood attended the International Maritime Organization (IMO) 2025 Workshop on the Relationship Between Ship Energy Efficiency and Underwater Radiated Noise (URN), an important milestone in the global effort to make shipping more efficient and less disruptive to marine life.
This year’s workshop builds on a series of IMO initiatives that have steadily advanced international attention on this issue.
Background
In July 2023, during the 80th session of the Marine Environment Protection Committee (MEPC), the IMO approved Revised Guidelines for the Reduction of Underwater Radiated Noise from Shipping, effective October 2023, to address the adverse impacts of vessel noise on marine ecosystems.
Later that year, in September 2023, the IMO hosted its first workshop exploring the relationship between energy efficiency and underwater radiated noise (URN), examining opportunities to improve both in tandem.
By October 2024, MEPC adopted a new revision, which included a URN Management Planning Reference Chart, effective December 2024, as well as a new Action Plan for the Reduction of Underwater Noise from Commercial Shipping. Among its key initiatives was a commitment to hold a second IMO-hosted workshop, the 2025 event attended by Mark, and to continue exploring how to align energy efficiency and URN objectives.
2025 Workshop Focus
The 2025 IMO workshop was structured around four key themes:
Day 1
- Theme 1: Updates on advances in technical energy efficiency and URN reduction.
- Theme 2: Integrated EE and URN management, including cost evaluation and incentivization schemes.
Day 2
- Theme 3: Moving toward integrated design standards for EE and URN.
- Theme 4: Using predictive models to evaluate co-benefits and guide future EE and URN objectives.
The overall goals were to:
- Understand ongoing and future trends in EE and URN technologies.
- Learn from real-world implementation of management planning and incentivization schemes.
- Advance integrated design standards.
- Strengthen collaboration among industry, government, academia, and civil society.
Workshop Insights
A recurring message throughout the sessions was clear:
We need affordable, reliable, and convenient ways to measure ship URN, especially at locations accessible to vessel operators.
A number of case studies showcased data collected using the Ocean Sonics icListen smart hydrophone, from the ECHO program to the MARS platform, used by researchers internationally, as well as BC Ferries who are leading the measurement and reduction of URN in a commercial setting. This work and use of the icListen technology highlights its role as a trusted tool for real-time acoustic data collection.
As Mark noted, this community is at a critical point in the Experience Building Phase (EBP), where theory, modelling, and policy are starting to meet real-world implementation. Discussions focused on how to make URN management more practical, scalable, and financially viable.
Four Key Takeaways
1. Make URN & EE financially attractive
Stakeholders emphasized that cost-effectiveness and measurable ROI are critical to encouraging widespread adoption. Early de-risking of new technologies and expanding access to measurement tools are essential.
2. Public perception matters
Beyond regulation, strong sustainability narratives and transparent environmental efforts offer significant public relations value.
3. Integrate URN into vessel design
While existing tools for modelling and design are strong, integrating URN mitigation into shipbuilding specifications from the start could accelerate progress.
4. Keep refining and iterating
Better modelling and faster iteration cycles will be key to reducing uncertainty and moving innovation from research to implementation more efficiently.
Participants also explored the potential to deploy URN measurement systems directly from the vessel of interest, creating opportunities for onboard, adaptive monitoring.
Another compelling discussion centered on the “Just In Time” shipping model, synchronizing vessel arrivals to minimize idle time and fuel consumption. If implemented broadly, this approach could deliver significant energy savings, though it would require major ecosystem-level changes across ports and operators.
Looking Forward
As the IMO and industry partners continue advancing these initiatives, it’s clear that URN reduction and energy efficiency are no longer separate goals, they are deeply interconnected pathways toward sustainable maritime operations.
At Ocean Sonics Ltd. , we’re proud that our icListen smart hydrophones are contributing to this international effort, helping researchers, regulators, and vessel operators measure, understand, and reduce underwater noise as part of a more energy-efficient and ocean-friendly future.
