National Defense Reserve Fleet
The National Defense Reserve Fleet (NDRF) consists of ships of the United States, mostly merchant vessels, that have been mothballed but can be activated within 20 to 120 days to provide shipping during national military emergencies, or non-military emergencies such as commercial shipping crises.
NDRF ships in Suisun Bay in San Francisco Bay
USS Iowa (BB-61) was in the custody of MARAD in the NDRF at Suisun Bay from 2001 to 2011.
Inactive U.S. Navy auxiliary ships in the James River near Fort Eustis in Newport News, Virginia
Mothballed ships in Suisun Bay in San Francisco Bay in 2010. The battleship USS Iowa can be seen at the far end of the first row
A reserve fleet is a collection of naval vessels of all types that are fully equipped for service but are not currently needed; they are partially or fully decommissioned. A reserve fleet is informally said to be "in mothballs" or "mothballed". In earlier times, especially in British usage, the ships were said to be "laid up in ordinary".
HMS Vanguard in about 1947, when it was part of the British Reserve Fleet
Ships of the U.S. Navy's Reserve Fleet in the Reserve Basin at the Philadelphia Naval Shipyard, 1956
HMS Unicorn in ordinary
