Thirt-seven years after the SS United States last sailed the seas under its own power, and four years after Norwegian Cruise Line bought the ship, a key question remains: Can the grand vessel ever make a comeback? Norwegian Cruise Line, or NCL, which bought the old Newport News-built vessel in 2003, won't reveal its plans for the ship, which likely would need hundreds of millions of dollars to refurbish. But in May, the chairman of the company that owns NCL gave boosters hope, saying "the restoration of the United States" would be the company's next project, after finishing off two planned cruise ships. Though it only carried about 2,000 passengers normally, it could be transformed into a military transport that could bring 14,000 troops to anywhere in the world in 10 days.