Bering Sea. From 9 June to 15 July 1969 Northwind conducted an oceanographic survey in the Chukchi Sea and Bering Sea, with Staten Island, and scientists from the University of Alaska Fairbanks and the University of Washington. On 26 June 1969 Northwind resupplied Fairway Rock. From 8 through 22 September 1969, Northwind, Captain Donald J. McCann, USCG, Commanding, and the Canadian icebreaker John A. Macdonald escorted the supertanker , of the Humble Oil and Refining Company, from Resolute Bay, Canada to Prudhoe Bay, Alaska where she was relieved by Staten Island on transit of the Northwest Passage. provided support during the eastward leg of the expedition. During the expedition Northwind lost a main engine bearing and the Engineer Division made repairs while underway, and went on to complete the Northwest Passage transit. Then, Northwind tested ice and returned to Seattle, Washington having transited and became the first surface vessel to conduct both a West to East and East to West transit of the Northwest Passage in a single season. 1970s From 20 January through 9 April 1970 Northwind conducted an Eastern Arctic patrol and oceanographic cruise. The cutter's northernmost penetration into the Arctic pack ice was at on 13 March 1970. This broke her 1967 surface vessel record by , and set a new record.<ref>Don McCune Library.USCG ICEBREAKER NORTHWIND,1970 documentary film. http://www.donmccunelibrary.com/catalog/dvds/uscg-noaa-expeditions/ Retrieved: 26 June 2015</ref> From 23 June through 28 September 1970 Northwind served on Arctic Operations. Her duties included laying cables, oceanographic studies, and re-supplying the Distant Early Warning Line. On 13 July 1970 Northwind rescued two crewmen from a ditched helicopter near the Yukon-Kuskokwim Delta in Norton Sound. With the discovery of oil on the North Slope of Alaska in 1971; Northwind surveyed the area, constructed aids to navigation for the North Slope and conducted ice research that year during Arctic West Summer. She also broke out an icebound convoy of twenty tugboats and forty barges en route to Prudhoe Bay, Alaska in 1971. From 1971 to 1972 Northwind sailed on Operation Deep Freeze to the Antarctic. She was once again in the Antarctic for Operation Deep Freeze from 1972 to 1973. During June and July 1973 Northwind conducted oceanographic research in Alaskan waters. On 1 January 1974 Venzke Glacier in Antarctica was named for Captain N.C. Venzke, USCG; who commanded Northwind from 1971 to 1973. From 1973 to 1975 Northwind underwent extensive machinery modernization and electronic