A floating offshore structure includes a buoyant hull including a first column, a second column, and a pontoon coupled to the first column and the second column. Each column is vertically oriented andthe pontoon extends horizontally from the first column to the second column. Each column has a central axis, an upper end, and a lower end. The pontoon includes a first tubular member and a second tubular member positioned laterally adjacent to the first tubular member. Each tubular member has a central axis, a first end coupled to the lower end of the first column, and a second end coupled to the lower end of the second column. The longitudinal axis of the first tubular member and the longitudinal axis of the second tubular member are disposed in a common horizontal plane.