Abstract :
The whole field of civil work in sonar and underwater acoustics is reviewed, discussing in particular the problems of short-range highresolution sonar and sonar for fisheries, the influence of micro-electronics on sonar philosophy, the growing importance of the exploitation of nonlinear acoustic wave interactions in sonar applications, and propagation, transducers and arrays. Civil applications of underwater acoustics are growing rapidly, and recent developments will lead to sonars of very high performance becoming available at a cost little (if any) greater than that of existing simple commercial equipments.
