This report concerns the early stages in the development of a new technology for underwater signature management. The aim of the work presented is on an anechoic coating with a tailored sonic velocity and absorption profile. Both a computational model to optimise the coating performance and the development of coating material are reported. In this initial stage of the development the coating is based upon homogeneous discreet layers rather then a gradient material. The individual layers are made up of polymer composite, where the matrix material is a styrene butadiene rubber (SBR) with nano- and micro-sized reinforcements.