Rodger N. Capps
U.S. Naval Res. Lab., Underwater Sound Reference Detachment, P.O. Box 568337, Orlando, FL 32856-8337
Extended towed array sensor systems are used for geophysical sensing and exploration in the petroleum industry, and for detection of submersible objects in naval applications. Many of the polymeric materials considered for use in towed array hoses either did not possess the necessary aging and weathering resistance; provided satisfactory self-noise performance at higher temperatures but were unacceptable in cold water; or experienced changes in self-noise through fill-fluid permeation and chemical reaction. There has been a need to develop and evaluate new classes of elastomers for use as hose wall materials. Array self-noise performance can also be improved through proper selection of polymers for use in vibration isolation modules for low-frequency towline excitation. Thermoplastic elastomers offer significant advantages over other types of elastomers in cost and ease of processing. Results are presented for both conventional elastomers and thermoplastics to show how these materials can be selected for the proper combination of Young's modulus and internal loss, tensile properties, ozone and weather resistance, resistance to swelling and permeation by seawater and fill fluids, adhesion to reinforcing members, for fabrication and evaluation as acoustic modules. Use of thermoplastics for vibration isolation modules is also discussed. [Work supported by NAVSEA PM 0425.]