The aim of the SONIC project is to develop tools to investigate and mitigate the effects of underwater noise generated by shipping, both in terms of the footprint of an individual ship (a “noise footprint”) and of the spatial distribution of sound from a large number of ships contribution to the sound (a “noise map”). The project`s first objective is to enhance the understanding of noise generated by a cavitating ship propeller. The second objective is to validate predictions of noise levels for individual ships, and to classify ships based on simplified noise models. SONIC’s third objective is to map the noise generated by shipping in general and to propose mitigation measures for quietening the oceans.From studies in marine biology it is known that the behaviour of large sea mammals as well as fish can be influenced by background noise. Cavitation of ship propellers has been identified as a main source of this background noise. The EU requires Member States to demonstrate that levels of underwater noise do not harm marine life. It is believed that cavitation noise from shipping traffic is largely responsible for low frequency ambient noise,a need has arisen for an improved understanding of the correlation between cavitation and background noise in the seas.The EU has set out on improving the environment within its member states by adopting the Good Environmental Status. This has been further defined in the Marine Strategy Framework Directive, in which it describes descriptors for measuring the environmental status. One of these descriptors is the underwater noise linked to among others maritime transport. It is stated that the reduction of underwater noise will be a measure for the improvement of the environment. SONIC will deliver the technical knowledge required for mapping, measuring and mitigating noise from shipping. The results of the SONIC project will contribute to quieting the oceans and improving the well-being of marine life.The SONIC consortium consists of world-leading hydrodynamic institutes, noise experts, propeller designers, reputable universities with specialised centres in this field, major European shipyards, and a class society; bringing together a wealth of knowledge on propeller cavitation and noise reduction. Interaction with the marine biology network has been established by obtaining necessary input to the project from renowned institutes in the field of marine biology. Furthermore, the consortium will aim for an open Advisory Board, consisting of a wide range of experts from the marine and maritime research communities, including members of the MARCOM+ forum.The SONIC project will be executed in close co-operation with the AQUO project, by sharing data, organising combined workshops and dissemination activities, and by joining forces on developing guidelines for industry and regulations.