Establishing a Benthic Cabled Observatory with ROV Based Cable Deployment

The Monterey Bay Aquarium Research Institute (MBARI) in support of the MBARI Ocean Observation System (MOOS) Science Experiment 2006 (MSE06) has established a benthic cabled observatory. The goal of MSB 06 is to study deep seafloor processes within and adjacent to the outer Monterey Bay Submarine Canyon. At the study site near Shepard Meander, a Benthic Instrument Node (BIN) and a McLane Vertical Profiler have been deployed in the axial channel of the canyon at depths of 3,450 meters. On the adjacent flank, outside the canyon another BIN has been deployed at a depth of 3,000 meters. These interdisciplinary BINs and profiler will be interconnected with a fiber optic/power cable using the ROV Tiburon. This will establish a network that can measure currents, suspended sediments concentrations, salinity, and temperature at these sites. The BINS and profiler will be cabled to a MOOS mooring. A satellite link from the mooring to shore will be used to monitor system function as well as deep sea conditions during the experiment. The ROV based cable deployments will consist of 3.5 kilometers between the lower and upper BINs, 2.5 kilometers between the upper BIN and the MOOS mooring and 200 meters between the profiler and lower BIN. Borrowing from the cable laying tool sled technology developed for the ROV Ventana (Bird 2002), this effort will integrate the knowledge gleaned from the Canyon Dynamics experience to the ROV Tiburon and MSE06. Some of the challenges involved in this project include weight constraints, power requirements, cable management, navigation, and electro/mechanical controls. In the future this technology will actively support the (Monterey Accessible Research System (MARS), and ORION/OOI. This presentation will deal specifically with the cable laying tool sled developed for the ROV Tiburon, cable packs, and infrastructure created to accomplish these tasks. Elements include the cable laying tool sled, BIN platforms, interconnects, profiler, mooring bottom expression, and cable handling equipment. Design elements includes; integration with the ROV Tiburon, meet operational weight constraints, the ability to (pick up, drop, and reacquire the cable spool), support the vehicle's Kraft Raptor manipulator, monitor cable payout speed and distance and a variable ballast system controlled by the amount of cable deployed. The operational procedure is, launch the vehicle at a BIN platform site with up to 4.5 km of cable on the spool. The vehicle will dive to the BIN, perform the interconnect, and establish a Doppler Velocity Log (DVL) bottom lock and enter coordinates of the location. Using the navigational program ArcNav, the vehicle will proceed along pre-mapped way points. The vehicle will follow the contours 1 to 2 meters off the bottom maintaining visually both the bottom and the cable as it is deployed. The maximum deploy speed will be .5 knot (.9 km) per hour. Deploying approximately 10% more cable length versus distance traveled will avoid tensioning the cable and forming spans. This will be accomplished using a graphic user interface that displays the amount of cable deployed versus the actual distance traveled across the bottom. Pay out speeds will be adjusted manually to match the speed of the vehicle. Upon reaching the BIN, the cable spool will be dropped, as an anchor, holding the excess cable. Using the manipulator, the connector will be removed from a dock within the cable spool body. A 20 meter service loop of cable on the exterior of the cable spool will allow the vehicle to maneuver to the BIN and perform the interconnect. In early July 2006 a successful cable lay of 2,800 meters, between the MOOS mooring and the shelf BIN was performed. In early October the remaining cable lays are scheduled