USNS Eltanin (T-AK-270)

USNS Eltanin (T-AK-270/T-AGOR-8) was an Eltanin-class cargo ship with an ice-breaking hull acquired by the U.S. Navy in 1957 and then operated by the Navy in a non-commissioned status, named after Eltanin, the star in constellation Draco. Her designation was changed to that of an oceanographic research ship in 1962 when she operated in Antarctic waters.

Built in Avondale, Louisiana
Eltanin (T-AK-270) was launched on 16 January 1957 by Avondale Marine Ways, Inc., Avondale, Louisiana. She was turned over to the Military Sea Transportation Service (MSTS) in October 1957 for operation in a noncommissioned status.

Conversion to research ship
During 1961 and 1962, Eltanin was modified throughout at a New York shipyard to fill a new role as a floating laboratory. Former cargo spaces were replaced with labs, workshops, and staterooms for scientists, and further labs were added above decks. Anti-roll tanks were also added, along with protective bulwarks. On 23 August 1962 her classification was changed to Oceanographic Research Vessel and designated T-AGOR-8.

Antarctic duty
Eltanin, under the direction of the National Science Foundation, and operated by the Military Sea Transportation Service, worked the Antarctic Ocean, becoming the first Antarctic research ship to do so. After two shakedown cruises in the Atlantic Ocean and a positioning cruise with further testing enroute, Eltanin operated a total of 52 Antarctic research cruises from July 5, 1962 thru December 29, 1972. Over this time, some 80% of the southern ocean was surveyed, and a total of 400,000 miles traveled.

Some of Eltanin's research cruises collected magnetic profiles of the sea floor that proved to be pivotal evidence in the acceptance of the continental drift theory, by proving the existence of sea floor spreading. These key profiles, which show symmetric bands of alternating magnetic orientation (corresponding to magnetic pole reversals) around various undersea ridges, are known by the ship's name and cruise number (ex. Eltanin-19).

As of mid-1973, Eltanin was laid up in San Francisco Bay, her research career at an end.

Inactivation
Eltanin was placed out of service at an unknown date and struck from the Naval Vessel Register, also at an unknown date, and transferred to the U.S. Maritime Administration for lay up in the National Defense Reserve Fleet. In 1974 she was transferred to the Argentine Navy and renamed ARA Islas Orcadas. She was later disposed of by the Argentine Navy in 1979.