Current Measurement System for Ocean Engineering

A deep ocean current measurement system is being developed to meet the present and future environmental data requirements for ocean engineering design and construction. This development is being supported by the Naval Facilities Engineering Command, the Naval Oceanographic Office, and the Director of Navy Laboratories. The specific system goal is for 95% probability of full data recovery after one-year implant. The speed accuracy will range from cm/sec at the threshold of 0.1 cm/sec to cm/sec at 51 cm/sec; from 50 cm/sec to 150 cm/sec the accuracy will be %. The direction accuracy will be magnetic from 0 to . The sensor will also measure water temperature to C. The system will be a single-point mooring with a predeployment packaging configuration of a Mark 45 torpedo. The system will be deployed and recovered by aircraft with an implant duration of one year in 6100 m of water. The in-line current sensor exploits the principles of hot film anemometry for measurement of both current speed and direction. The problem of contamination is addressed by a combination of antifouling coating, sonic cleaning, and in-situ calibration. Although this paper describes the entire system, it emphasizes both theoretical and experimental work with the sensor. To date, all developmental efforts have been in the sensor area and sensor-related areas.