USC&GS Explorer (OSS 28)

The second USC&GS Explorer (OSS 28) was a survey ship that served in the United States Coast and Geodetic Survey from 1940 to 1968. She operated in the Pacific Ocean from 1940 to 1960, seeing service there during World War II, and in the Atlantic Ocean from 1960 to 1968.

Construction and commissioning
Explorer was built by Lake Washington Shipyard at Houghton, Washington, as an "ocean survey ship" (OSS) for the Coast and Geodetic Survey launched 14 October 1939 and delivered 9 March 1940. Detailed design and unusual construction procedures were developed from government designs by the Seattle firm of W. C. Nickum Sons. She was commissioned in the spring of 1940 as USC&GS Explorer (OSS 28).

Explorer was designed with over 90% fireproof materials with Johns-Manville asbestos Flexboard paneling covering all interior spaces. Designed for six month independent deployment with capability to service smaller vessels and shore stations the ship included a hospital, machine, electrical and carpenter shops and a laundry.

Service history
Explorer entered service in time to take part in the 1940 field season, during which she was assigned to conduct hydrographic surveys in the Aleutian Islands westward from Umnak Island. After an assignment in the Strait of Juan de Fuca-San Juan Islands area of Washington during the winter of 1940-1941, she returned to the Aleutians for the 1941 field season to survey the waters westward from Yunaska Island. After the conclusion of the 1941 season in the Aleutians, she began survey work around Midway Atoll, but was recalled from Midway after the Japanese attack on Pearl Harbor of 7 December 1941 brought the United States into World War II. Steaming from Midway to Honolulu, Territory of Hawaii, she rescued the crew of an aircraft which had ditched in the Pacific Ocean due to fuel exhaustion. She then returned to the Aleutians for the 1942 field season, extending triangulation work as far as the eastern end of Atka Island and hydrographic suveys as far as Seguam Island. During the season, in June 1942, the Aleutians became a front-line combat area after Imperial Japanese Navy aircraft attacked Dutch Harbor and Imperial Japanese Army and Navy forces occupied Attu and Kiska, beginning the Aleutians campaign.

After the conclusion of Aleutians work in 1942, Explorer returned to survey operations around the San Juan Islands in Washington and performed wire-drag survey work around the Hein Bank with USC&GS Patton, but during the 1943 season she resumed operations in combat areas in the Aleutians as U.S. and Canadian forces drove the Japanese out of the islands. On one occasion during the fighting in the Aleutians in 1942-1943 she fought off an attacking Imperial Japanese Navy aircraft. In 1944 and 1945 she continued to operate in support of U.S. Navy World War II hydrographic needs in the Aleutians until Japan surrendered in August 1945, bringing the war to a close. Postwar, she spent the 1946 field season in the Aleutians cooperating with the Coast and Geodetic Survey ships USC&GS Surveyor and USC&GS Derickson in extending an arc of triangulation from Kiska to Attu, completing an arc extending across the continental United States, Territory of Alaska, and Aleutians, and conducted triangulation, topographic, and hydrographic surveys in the coastal waters north and south of Attu and in other parts of the Near Islands.

In 1960, Explorer transferred to the United States East Coast, where she spent the remainder of her career, focusing mainly on oceanographic research. In 1963, she participated in the EQUALANT I and EQUALANT II subprojects of the International Cooperative Investigations of the Tropical Atlantic (ICITA) project, the first international cooperative oceanographic/meteorological project in which a United States Government scientific agency took part.

The Coast and Geodetic Survey retired Explorer in 1968.