USC&GS Oceanographer (OSS-26)

The first USC&GS Oceanographer (OSS-26) was a survey ship that served in the United States Coast and Geodetic Survey from 1930 to 1942.

Construction and early career, 1899-1930
Oceanographer was built as the private yacht Corsair II for the industrialist J. P. Morgan, Jr., in 1899; sources differ as to her builder, but it was either T. S. Marvel and Sons at Newberg, New York, or W. & A. Fletcher Company at Hoboken, New Jersey. In 1917, the U.S. Navy acquired Corsair II from Morgan for World War I service and commissioned her as the patrol vessel USS Corsair (SP-159). Corsair was returned to Morgan in 1919 and once again became Corsair II.

United States Coast and Geodetic Survey career
On 2 January 1930, the Coast and Geodetic Survey purchased Corsair III from Morgan for $1.00 (USD) for use as a survey ship, and placed her in service as USC&GS Oceanographer (OSS-26) that year. Oceanographer operated along the United States East Coast during her career with the Survey.

Oceanographer conducted many offshore surveys and discovered many of the canyons incising the continental slope between the Georges Bank area and Cape Hatteras, North Carolina. She also supported the study of geophysics when Maurice Ewing conducted his first seismic reflection profiling experiments from her in 1935.

On 23 August 1933, Oceanographer and the Coast and Geodetic Survey steamers USC&GS Lydonia and USC&GS Gilbert handled considerable radio traffic for Norfolk, Virginia, during the 1933 Chesapeake–Potomac hurricane, which struck the city on that date and set records for high water levels. Oceanographer's commanding officer, H.A. Seran, reported that the ship's radio plant was for a time during the height of the hurricane the only means of communication from Norfolk to points outside; during this time, Oceanographer handled all radio traffic for the U.S. Navy, as well as for commercial companies.

In January 1937, crewmembers of Oceanographer and Lydonia were detached to man Coast and Geodetic Survey launches under the direction of the Red Cross during flood relief efforts at Kenova, West Virginia.

On 7 April 1942, Oceanographer was transferred to the U.S. Navy at Norfolk for World War II service

Return to U.S. Navy service
The Navy initially classified Oceanographer as a gunboat and renamed her USS Natchez (PG-85), but quickly reclassified her as a survey ship and renamed her USS Oceanographer (AGS-3). She operated in the Navy until 1944, when she was decommissioned. She later was sold for scrapping.

Commemoration
In recognition of her survey work off the U.S. East Coast, the underwater features Oceanographer Canyon and Corsair Canyon—the latter name derived from her name as a World War I U.S. Navy patrol vessel and private yacht prior to her Coast and Geodetic Survey career—are named for Oceanographer.