Floating wind turbine assembly comprising a floating platform with at least three coplanar buoyancy tanks (13,14,15) at least three of which are radial buoyancy tanks, wherein the at least three radial buoyancy tanks are coplanar and substantially equidistant from the central structure, the floating platform further comprising: a wind turbine arranged on top of the floating platform, the wind turbine having a mast with a mast axis, of which a lower end is connected to the floating platform, and a nacelle arranged on top of the mast, wherein the floating platform is connected to a seafloor with a plurality of tensioned mooring lines, wherein the mooring lines each comprise a mooring line axis extending in a longitudinal direction of the mooring line, a substantially horizontal truss structure having an upper level and a lower level; and a central structure at a central position; wherein the truss structure connects the buoyancy tanks at the lower level, characterized in that the lower end of the mast is connected to the floating platform at the upper level, above the central structure, wherein each mooring line comprises an incremental tensioning system, the incremental tensioning systems being adapted for acting on the mooring lines by tensioning the mooring lines in such a way that the buoyancy tanks (13,14,15) are submerged from a position in which they pierce the sea surface and provide a hydrostatic stability, to a position in which the buoyancy tanks as well as the truss structure have been submerged into the water with the radial buoyancy tanks below the water surface, during which submerging the hydrostatic stability conferred by the buoyancy tanks (13,14,15) piercing the water surface is progressively transferred to the mooring lines, so that, when in an operational configuration, the tensioned mooring lines confer a mooring stability. a wind turbine arranged on top of the floating platform, the wind turbine having a mast with a mast axis, of which a lower end is connected to the floating platform, and a nacelle arranged on top of the mast, wherein the floating platform is connected to a seafloor with a plurality of tensioned mooring lines, wherein the mooring lines each comprise a mooring line axis extending in a longitudinal direction of the mooring line, a substantially horizontal truss structure having an upper level and a lower level; and a central structure at a central position; wherein the truss structure connects the buoyancy tanks at the lower level, characterized in that the lower end of the mast is connected to the floating platform at the upper level, above the central structure, wherein each mooring line comprises an incremental tensioning system, the incremental tensioning systems being adapted for acting on the mooring lines by tensioning the mooring lines in such a way that the buoyancy tanks (13,14,15) are submerged from a position in which they pierce the sea surface and provide a hydrostatic stability, to a position in which the buoyancy tanks as well as the truss structure have been submerged into the water with the radial buoyancy tanks below the water surface, during which submerging the hydrostatic stability conferred by the buoyancy tanks (13,14,15) piercing the water surface is progressively transferred to the mooring lines, so that, when in an operational configuration, the tensioned mooring lines confer a mooring stability.