The region where the North Atlantic Current crosses the ocean around 50N is studied from a watermass point of view and using the ventilated thermocline model of Luyten et al. (1983). Both approaches focus on the part played by the Subarctic Intermediate Water which, owing to its pronounced thermohaline anomalies stands out as a clue to the complex oceanic circulation in this area. Vertical mixing of this watermass with the overlying North Atlantic Central Water creates a fresher variety of central water found between the two major branches of the North Atlantic Current. Using the ventilated thermocline model several tracks are explored to try to reproduce the subduction of Subarctic Intermediate Water, its movement into the subtropical region, and quick return to the western boundary.