A boomerang type buoy for measurement of near bottom currents in the deep ocean

A bottom-mounted deep current measuring system has been developed at the Naval Air Development Center. The system provides long-term, near-bottom current data which is being used to study both the nature and movement of large scale eddies in the near-bottom ocean and the effect of local topographical features on near-bottom currents. The system, termed the ROBOTS CURSOR (Remote, On-the-Bottom, Over-the-Side, Current Sensor), employs up to four recording current meters suspended by a single cable at selectable distances from the ocean bottom. Current data can be recorded for periods up to 30 days. Buoyancy is provided by a framework of 41 cm (16 inch) diameter glass spheres. Location of the deployed ROBOTS and its release are accomplished using a pair of acoustic release/transponders arranged in parallel. ROBOTS has been successfully deployed and recovered in the deep ocean at the eastern end of the Puerto Rico trench. Current and temperature data measured 15 to 50 meters from the bottom in depths to 3000 meters are presented. Current speeds varied from zero to 9 cm/sec/ (0 to 0.18 km) with direction spanning 360 degrees.