The U.S. Navy is transforming a costly flub into a potent weapon with the first shipborne hypersonic weapon, which is being retrofitted aboard the first of its three stealthy destroyers. The USS Zumwalt is at a Mississippi shipyard where workers have installed missile tubes that replace twin turrets from a gun system that was never activated because it was too expensive. Once the system is complete, the Zumwalt will provide a platform for conducting fast, precision strikes from greater distances, adding to the usefulness of the warship. “It was a costly blunder. But the Navy could take victory from the...