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Subsea instrument deployments: methodology and techniques using a work class remotely operated vehicle (ROV)

The conventional deployment of sensors and data-logging equipment by free fall from the ocean's surface is fraught with many technical problems, including unpredictable instrument placement, lack of control over site selection, unreliable instrument orientation, lack of communications with the instrument during deployment, and short measurement duration due to limited battery power. Through several experiments, MBARI has attempted to reduce or eliminate the impact of a number of these problems by utilizing the communicative and manipulative capabilities of the ROV Ventana. The development of corehole seismometers required methods to maintain the connection to a data logger during the deployment, and then allow in situ connection of the logger to an instrument to verify data collection and integrity in real time. The Monterey Bay Ocean Bottom International Seismic Experiment (MOISE) allowed for specific site selection and preparation prior to instrument deployment, real-time data access, control and verification of instrument and data integrity, and the ability to revisit the site to access both the instrument and data logger as well as supply additional power. The Autonomous Video Camera System (AVCS) allows selection of sites or subject matter for long-term video observation with the ability to verify the operation and target subject prior to disconnection of the ROV from the camera system. The One- and Two-Meter Hydraulic Tube Coring experiments allowed for precise placement and controlled execution of sediment coring operations. The preceding are some development efforts that demonstrate how technical and methodological problems were approached. By the very nature of the solutions, new questions have arisen and more advanced methods of achieving technical goals are being pursued.