Noise and Vibration

A growing attention has been devoted recently to acoustical problems on board of vessels, particularly in connection with the construction of an increasing number of high standard cruise vessels and pleasure crafts. Severe specifications on maximum noise levels on board, in particular in working, living, and resting areas are now common, reflecting into the need for a careful acoustical planning since the very first steps of the design. This approach implies in general a detailed analysis of the various elements of the “acoustic circuit” with identification and characterisation of the sources present on board, of receiving positions (location and required limits) and of transmission paths connecting them. In principle, actions on any of these elements are possible, but not always they all are practically feasible: in any case the strategy to be adopted should be chosen since the beginning, in order to have the maximum flexibility in the solutions: “a posteriori” actions are often incomplete, uneconomical, and can bring a considerable increase in weight. The present work aims at defining the physical meaning of the various elements of noise transmission and the way of acting on them.