Abstract: The invention describes a submerged sensor for use in a metallurgical vessel, such as a tundish. The sensor is positioned so that in use it is below a surface of a molten metal bath within the vessel. The sensor conveniently extends through the vessel wall and projects into the volume of the vessel. An upper end of the sensor is encased in a protective assembly. The protective assembly of the invention can be shaped so as to control the pattern of molten metal flow in the vessel or measure more accurately the molten metal exiting the vessel. Advantageously, the invention can combine the functionality required for flow pattern modification such as provided by a dam, impact pad or baffle, with the functionality required for a sensor. This combination reduces cost and complexity.