LOWNOISER - Lowering underwater noise radiation from waterborn transport

Underwater Radiated Noise (URN) from ships is among the most significant human-made noise sources in the marine environment. While shipping has long been recognized as a low-carbon mode of transport, the noise it generates under the water's surface has often been overlooked in assessing impacts on marine species. In March 2024, the European Commission introduced threshold values addressing habitat loss due to continuous underwater noise, setting a benchmark that no more than 20% of the habitat of target species may exceed the Level of Onset of Biologically adverse Effects (LOBE)—effectively requiring that 80% of the habitat remains unaffected. Although no explicit ship noise limits are mandated, member states must evaluate the conservation status of their waters and take action where needed.

Awareness of underwater noise has lagged behind airborne noise, where human exposure accelerated regulation and mitigation (e.g., jet engine noise abatement). In the marine domain, recognition has grown through research and projects which have advanced criteria for assessing URN’s harm and explored measures to reduce it, including addressing cavitating propellers. Other initiatives shifted focus toward regulating ship noise emissions and implementing practical solutions.

LOWNOISER builds on this foundation, aiming to demonstrate the effectiveness of high‑TRL noise reduction technologies, measures, and management strategies at full and large scale. The project also advances predictive tools for URN and validates that mitigation solutions can be environmentally aligned (low GHG), economically viable, and operationally safe. By turning proven science into real-world demonstrations, LOWNOISER brings us closer to quieter oceans and healthier marine ecosystems.

SINTEF Ocean conducts experiments in the cavitation tunnel to measure effect of different noise mitigation measures, including air lubrication, and improves analytical methods for noise prediction of ships and its abatement. Kourosh Koushan is the innovation manager of the project.