IN DEPTH ENVIRONMENTAL PROTECTION KEEPING THE NOISE DOWN
Reducing underwater radiated noise from operations is a task best managed at the vessel design stage, writes Jukka Suvanto, senior sales manager at engineering and
E
nvironmental accountability is a fundamental priority in the maritime industry’s agenda.
Alongside the need to reduce shipping’s carbon emissions, shipbuilders and operators are increasingly expected to minimise their impact below the waterline. One of the most widespread yet underregulated issues caused by maritime operations is underwater radiated noise (URN), a persistent, human-induced low-frequency noise that affects 91% of European oceans, due to continuous noise from commercial shipping.
While the International Maritime Organization (IMO) released non-mandatory Revised Guidelines for the Reduction of URN in 2023, legally binding global regulation is still lagging behind the science. However, effective methods have been developed to support the mitigation of URN emitted from ships. Through proactive investment in noise-reduction technologies at the design phase, owners and operators are able to future- proof their vessels to ensure compliance with evolving regulatory frameworks.
The impact of URN URN is primarily generated from a ship’s propellers and engines, as well as from sonar, seismic surveys and construction activities such as piling and dredging. The creation of continuous low-frequency noise disrupts the surrounding marine ecosystem, particularly mammals, where prolonged exposure to URN can result in immense discomfort, impacting their ability to communicate. The effects of underwater noise in marine mammals range from chronic stress to changes in mating, hunting and migration behaviour, triggering consequences that can cascade throughout entire ecosystems.
Despite the detailed understanding of the impacts that URN has on the surrounding environment, continues to operate without IMO’s 2023 revision of its URN guidelines represents a step forward; however, without mandatory enforcement, the incentive for widespread change remains low.
Jukka Suvanto, Elomatic: “Reducing vessel speed, applying wind-assisted propulsion or installing air lubrication systems can all help reduce underwater noise”
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“Without binding international regulations, industry progress remains uneven”
With regards to regional regulation, the EU addresses URN mitigation as part of its Marine Strategy Framework Directive (MSFD), which establishes that no more than 20% of a marine area can be exposed to continuous underwater noise, which is categorised under both impulsive noise (piling and seismic surveys) and continuous noise (vessel operations).
However, as detailed global regulation continues to develop, industry organisations are seizing the initiative through the introduction of positive measures to help address this issue. Incentive programs, such as port fee reductions in Vancouver and Prince Rupert, Canada, are encouraging operators to address noise pollution from their vessels. For example, these ports offer tax reductions for vessels that meet noise reduction criteria, with large containerships able to earn up to CAD4,000 (€2,700) per call.
Uneven progress Further showcasing this growing momentum, in June 2025, following the 3rd UN Ocean Conference, leaders from 35 countries launched the High global political alliance dedicated to tackling underwater URN.
Although these initiatives highlight a growing awareness of the need to introduce meaningful mitigation measures without binding international regulations, industry progress remains uneven. The lack of enforceable requirements continues to add long-term ecological protection.
To support the industry’s efforts, Elomatic has partnered with Aalto University in Finland to develop concepts that can predict the level of underwater noise a vessel will generate during the design phase, thereby negating through the use of smarter design methods. This predictive noise simulation framework can be applied early in the ship design phase, allowing naval architects and shipowners to minimise acoustic impact before a single plate is cut.
THE NAVAL ARCHITECT
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