Skywatcher (YAGR-3) was laid down on 30 November 1944, under a Maritime Commission (MARCOM) contract, MC hull 2337, as the Liberty Ship Rafael R. Rivera, by J.A.

She was launched on 16 January 1945; sponsored by Mrs. Evelyn Anderson; and delivered 25 June 1945, to the States Marine Corporation.

Rafael R Rivera moved horses, heifers, and mules, as well as a some chicks, rabbits, and goats.

[7][8][9] She was acquired by the U.S. Navy on 20 September 1954, and converted at the Portsmouth Naval Shipyard, Norfolk, Virginia, into an ocean station radar ship.

[5][4] In July 1955, she assumed her first duties in the Contiguous Radar Coverage System of the United States while operating out of Newport, Rhode Island.