Upon completion of her 15th Western Pacific deployment on 14 October 1963, Navasota was scheduled for "jumboization", the first oiler so designated. She steamed on 14 November 1963 for Puget Sound Naval Shipyard at Bremerton, Washington, for preliminary preparations, then entered Puget Sound Bridge and Drydock Company, Plant No. 2, Harbor Island, Seattle, Washington for the conversion. Her new 394-ft (120.1 m) midsection was built in Kawasaki Dock Yard, Kobe, Japan, and towed to Seattle by the Japanese tug Daisho Maru No. 1.