Mercy was built as an oil tanker, SS Worth, by National Steel and Shipbuilding Company, San Diego, California, in 1976. Starting in July 1984, she was renamed and converted to a hospital ship by the same company. Launched on 20 July 1985, USNS Mercy was commissioned on 8 November 1986. She has a raised forecastle, a transom stem, a bulbous bow, an extended deckhouse with a forward bridge, and a helicopter-landing deck with a flight control facility. The Mercy class hospital ships are the third largest ships in the U.S. Navy Fleet by length, surpassed only by the nuclear powered Enterprise and Nimitz-class Supercarriers