In 1971, as in every summer since she became a U.S. Coast Guard icebreaker, "Edisto" took part in "Arctic East Summer" (AES) operations. In December 1971, she was temporarily transferred to Milwaukee, Wisconsin to take part in a test, along with of icebreaking operations designed to extend the length of the shipping season on the Great Lakes and the Saint Lawrence Seaway system. In the autumn of 1972, however, "Edisto" conducted icebreaking operations off Greenland in concert with the U.S. Navy oceanographic research ship . She was sent there from the Great Lakes after the cutter originally assigned the duty, , suffered an engine casualty; although she remained off Greenland. "Edisto" arrived in the Arctic on September 30, 1972 and began escorting "Mizar" into the icepack for oceanographic research. At one point, the two were as far as into the heavy ice, some of which was a thick as . In early October 1972, one of the "Mizar"s engines went out, so "Edisto" took her in tow, intending to take the research vessel out of the ice. On October 6, 1972, "Mizar" slipped out of its tow with "Edisto" and collided with the icebreaker, doing minor damage to "Edisto"s starboard side superstructure. Later, "Edisto", due to the heavy ice; lost her starboard propeller and damaged her rudder and starboard shaft.