Abstract: A turbine replacement unit for replacement of at least one double runner horizontal submersible installation for a hydroelectric plant including at least one submerged coupling and at least one submerged bearing supported by a submerged bearing pedestal in which each of the two runners discharge a flow into a common draft tube. The replacement unit includes a single runner positioned to replace each of the two runners, the single runner receiving a flow and discharging the flow into the existing common draft tube. A dry pit assembly is positioned to surround the submerged pedestal and define an air space around the submerged pedestal and an oil-flooded bearing is positioned on the pedestal to replace the submerged bearing. A shaft supports the runner for rotation and is at least partially supported for rotation by the oil-flooded bearing. A generator is coupled to the shaft and is operable to produce an electrical power in response to rotation of the shaft.