The float structure is constructed with a bottom structure providing buoyancy to the float structure, an upper deck and a number of support columns that connect the bottom structure and the equipment deck which is to be positioned above the surface of the water in which the float is arranged to operate. The float structure is characterized in that at least one of said support columns comprises a liquid storage column which is placed in the middle section of the float structure with the remaining support columns are positioned in the outer sections of the float structure. Active ballast tanks are disposed in the middle section of the bottom structure adjacent the liquid storage column and secondary ballast tanks are disposed in the outer part of the bottom structure.