Monitoring corrosion in submarine sonar domes

The Applied Physics Laboratory at the University of Washington (APL-UW) and the Naval Sea Systems Command (NAVSEA) are involved in a long-term study to reduce corrosion in submarine sonar domes. Besides periodically inspecting the structures in tile domes and recommending improvements in their design, materials, and maintenance, APLUW has recently developed an instrument package to monitor selected parameters of the dome water in situ. Previously, analyses of dome-water corrosivity combined information from three sources: water samples collected as the dome was pumped out, pierside measurements, and laboratory tests of the electrochemical corrosion rate of typical materials used in the dome. With this procedure, dome water samples were obtained only at the end points of the operation cycle, i.e., during maintenance prior to and following patrol. The new instrument package (called the Dome Water Monitoring Instrumentation System, or DWMIS) monitors and records dame-water parameters such as salinity, conductivity, pH, temperature, dissolved oxygen, and galvanic potential periodically each day to establish changes and trends. The goals of this monitoring program are to understand dome water corrosivity and how the corrosivity is affected by the exchange rates between the dome and surrounding, external seawater. The knowledge gained will be used to formulate recommendations for reducing the corrosivity of the dome water.<>