The National Defense Reserve Fleet (NDRF) consists of "mothballed" ships, mostly merchant vessels, that can be activated within 20 to 120 days to provide shipping for the United States of America during national emergencies, either military or non-military, such as commercial shipping crises.
The NDRF is managed by the U.S. Department of Transportation's Maritime Administration (MARAD). It is a different entity from the United States Navy reserve fleets, which consist largely of warships.
NDRF vessels are at the fleet sites at James River, Virginia–the 'James River Reserve Fleet'; Beaumont, Texas–the 'Beaumont Reserve Fleet'; and Suisun Bay, California; and at designated outported berths. Former anchorage sites included Stony Point, New York - the Hudson River Reserve Fleet; Wilmington, North Carolina; Mobile, Alabama; Astoria, Oregon; and Olympia, Washington.
Through the 2010s, the oldest, most decrepit hulls at Suisun Bay will be stripped of toxic materials, then broken up in Texas, California or Asia. Twenty of the most polluting mothball ships are slated for recycling by 2012, as are 32 more by 2017.
At its peak in 1950, the NDRF had 2,277 ships in lay-up. In 2003, it had 274. In July 2007, it held 230 ships, primarily dry cargo ships with some tankers, military auxiliaries and other types. By the end of August, 2015, it held 100.
The NDRF was established under Section 11 of the Merchant Ship Sales Act of 1946 to serve as a reserve of ships for national defense and national emergencies.
NDRF vessels were used in seven wars and crises. During the Korean War, 540 vessels were broken out to move military forces. During a worldwide tonnage shortfall in 1951–53, more than 600 ships were reactivated to carry coal to Northern Europe and grain to India. From 1955 through 1964, another 600 ships were used to store grain for the Department of Agriculture. Another 223 cargo ships and 29 tankers were activated during a tonnage shortfall after the Suez Canal was closed in 1956. During the Berlin crisis of 1961, 18 vessels were activated and remained in service until 1970. Another 172 vessels were activated for the Vietnam War.