The Sea Data 651-4 data logger

This paper describes a digital data logger used as the primary controller and data collection device for the U.S. Geological Survey Sediment Monitoring Tripod Program. The tripods are deployed at sea in water depths up to 100 m for periods of 3 to 6 months. The system measures bottom current speed and direction, pressure, temperature, light transmission, and photographs the bottom. This report is intended to provide a description of the unit and its operation.