ATR-20 was laid down by Camden Shipbuilding & Marine Railway Co., Camden, Maine, 20 January 1943; launched 18 October 1943; sponsored by Miss Joy D. Creyk; transferred to the United Kingdom under lendlease 24 April 1944; and commissioned as HMS Justice at Boston, Massachusetts, the same day, Lt. J. S. Allison, RNR, in command.
During the remainder of World War II, Justice served as a rescue tug in the Royal Navy. She reportedly served at the Normandy invasion in June 1944.
Justice was returned to the U.S. Navy on 20 March 1946 and redesignated BATR-20. She was struck from the Naval Vessel Register on 3 July 1946 and sold 3 October 1947 to Leopoldo Simoncini of Buenos Aires as the Costa Rican-flagged St. Christopher. In 1953 she was chartered for salvage operations in Beagle Channel on the sunken Hamburg South America Line ocean liner SS Monte Cervantes along with several Argentine Navy vessels.
After suffering engine trouble and rudder damage in 1954, she was laid up at Ushuaia.