PRACTICAL NOISE REDUCTION IN SHIPS

The aim of this paper is to assist in the reduction of noise by "on ship" palliatives rather than by measures taken at the design stage. It is, however, mentioned that the degree of improvement possible by such palliatives is limited. The ear can hardly detect noise reductions of less than 3 dB, and a 10-dB improvement must be obtained before loudness is halved. Thus, solutions giving reductions of one or two decibels are barely worthwhile except to meet contract obligations. The Authors (of Southampton University) explain the nature of sound and its transmission. The various shipboard noise-sources and associated phenomena are then discussed under the headings; Engine Room Noise; Reduction of Noise obtained by Encapsulation of an Engine; Steam Leakage Noise; Valve Noise; Engine Room Rafting; Noise Transmission throughout a Ship; Silencing of Deck Areas; Low-Frequency Noise Problems. Included under these headings are case studies of some actual noise problems, with explanations, in some detail, of the methods used to combat them.