Eight Years Underwater–The Development of a Reliable and Configurable Underwater Sensor System

This paper describes the development, testing, and endurance of a digital array sensor system that can be built to suit almost any application. The array system can support any desired number and mix of different transducer types with a very wide range of sampling rates. Examples of the arrays are shown in the paper to illustrate the ability to operate in air and underwater to depths of 5000m with varying system size from centimetres to kilometres. During development of the technology, underwater deployments lasting one and two years were carried out. Following testing, an operational system was deployed underwater for a continuous eight-year period. An analysis of data from the arrays was conducted after three years underwater and it was shown that the data were of high quality. Both arrays continued to operate for the full seven years after which one array failed. During an attempted recovery in the eighth year the second array failed due to damage to its underwater cable which was entangled with the first array cable. Both arrays have likely been limited by the telemetry and power cables; however, we won't know for certain until the arrays and cables have been recovered.