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The evaluation of the acoustic impact of ships is a complex problem, involving not only different sources but also different kinds of receivers and transmission paths. The problem of health and comfort for crew and passengers on board has been considered since a few decades, leading to quite a structured and detailed framework of Norms and Requirements. On the other hand, only in recent years a growing attention has been devoted to air-borne noise emissions outside the ship, for which requirements are not present. Underwater noise emissions have, even more recently, gained attention for their potential interference with mammals' communications and with the sophisticated use such animals make of acoustic signals for interacting with their living environment. An aim of the present work is to review the state of the art in the three areas above identified outlining the differences in the specific fields as regards: The present knowledge of the phenomena involved; the accuracy of the models available for the description of noise propagation; the accuracy of the models available for the quantification of noise effects.

Marine and offshore regulations about onboard noise are quite stratified and tangled, being issued by a number of international and national bodies. At the same time, many of the requirements are actually expressed in non quantitative terms and neglect parameters like noise spectra, low frequency pulsations or sound reverberation, which deeply influence the “sound wellness”. Aim of this paper is therefore to improve present requirements by introducing more meaningful noise annoyance criteria. These new criteria should be at the same time able to better express the actual reactions to noise from crew and passengers and simple enough to be widely applied on board ships. Such enhanced criteria are derived from the noise rating methods provided to rate indoor background sound in the civil engineering context. The possibility to make use of these indicators in the naval field is analyzed and some recommendations for a proper application on ships are given.

To assess and to control the environmental noise due to the main noise sources, including ports, the European Directive 2002/49/CE introduced a tool for the acoustic planning: The Noise Strategic Mapping (NSM). In any harbor, NSM can be obtained by evaluating the sound field for each type of sound sources standing in the port area and by superimposing all noise contributions. The present paper suggests a method to achieve such acoustical analysis of port noise. The method has a general purpose and is implemented in four steps: definition of the vessels category; measurements to characterize ship as a noise source; modeling of outdoor noise propagation; map drawing. All these subjects are discussed in the paper and some specific recommendations to get at a successful noise mapping of ports are reported, too. In the end, limit values to keep under control the problem of noise pollution due to ships are proposed.