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OOI's Electro-Optical-Mechanical (EOM) test buoy, stowed on the fantail of the R/V Connecticut, was deployed in January, 2010 on a mooring in 152 meters of water on the continental shelf break south of Woods Hole. The test mooring was designed to evaluate the performance of EOM stretch hoses and the first application of a high speed satellite telemetry system, the Inmarsat based FleetBroadband 250, on a small moored platform. (Photo by Tim Scholz, Woods Hole Oceanographic Institution)

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50 Years of the WHOI Buoy Group50 Years of the WHOI Buoy Group
For over 50 years the WHOI Buoy Group has set out to develop ways to discover what was happening far beneath the ocean surface and to explore the complex interactions between sea and air.


Ocean processes don’t start and stop with the arrival and departure of an oceanographic research vessel. Currents are ceaselessly moving, plankton constantly bloom, the seafloor is continually being built—all of it happening over months, years, and decades.

In order to collect long-term views of these and other processes at work in the ocean, scientists and engineers have devised ways to leave instruments out in the environment. Moorings—secured by wires, buoys, weights, and floats—are platforms which allow us to observe how the ocean and seafloor change.

Most of us are familiar with common moorings, which use anchors and cables or ropes to secure boats, channel markers, and other floating objects in fixed places in our waterways. Fixed oceanographic moorings work on the same principles, but the lines can be thousands of meters long and may or may not poke above the surface of the water. Scientific instruments can be attached to the mooring line, mounted on a surface buoy, or made to climb up and down the underwater line.

Coastal and Global Scale Nodes Moorings

CGSN moorings are innovative and more capable mechanically and electronically than previous oceanographic designs.

The moorings use a combination of nylon-jacketed steel wire rope, various types of synthetic line, electromechanical (EM) cable with copper conductors and electro-optical mechanical (EOM) cable with copper conductors and optical fibers. Steel wire rope can be used not only for strength and resistance to fish-bite but also for inductive telemetry of data from moored instrument packages.

With inductive telemetry, a controller on the mooring (usually at the buoy) can receive data and send commands to instruments on the mooring line below. The wire rope also provides the pathway for wire-following profilers to ascend and descend by traction motors or buoyancy control.

Surface moorings
Coastal EOM (Electro-Optical-Mechanical)
Coastal EM
Coastal Profilers
Coastal Hybrid Profiler

Subsurface moorings
Global Flanking
Global Hybrid Profiler