Tube Investments of India (TII), a Murugappa group company, has more than doubled its net profit for the year ended March 31, 2011, to Rs. 169.66 crore as compared to Rs. 81.21 crore in the previous year. Total revenue during the year under review shot up to Rs. 2,981.10 crore against Rs, 2,358,49 crore in the previous year, said a press release in Chennai on Tuesday.