The Navy's methods for estimating the initial costs of its $21 billion plan to improve the four public shipyards create risks that "together could add billions to the ultimate cost," according to a government watchdog. The conclusion came from a new Government Accountability Office report written in response to a Fiscal Year 2019 National Defense Authorization Act requirement. Lawmakers asked GAO to review the extent to which the Shipyard Infrastructure Optimization Plan addresses deficiencies in the Navy's infrastructure, includes reliable...