In this project, investigators will deploy deep, current-following RAFOS floats over a four-year period in the Deep Western Boundary Current off Cape Hatteras in the vicinity of the Blake Plateau in the western North Atlantic Ocean. Recent direct current measurements suggest that there are several components to this "current", whereas tracer studies suggest a single broad thermohaline current driven by the formation of deep water in the Northern North Atlantic. Deployment of RAFOS floats in three separate components of this deep recirculation, and tracking them over a three-year period, will allow the P.I. to more accurately describe this current regime, and to better calculate the heat, salt, and momentum balances in a region that is a key to the circulation and transport of the entire North Atlantic Ocean.