A structure erected to handle drill tools.
(YO-59: dp. 393; l. 235'; b. 37'; dr. 15'; s. 10 k.)
Derrick (YO-59) was built by R. T. C. Shipbuilding Corp., Camden, N.J., and commissioned on 2 February 1943, Lieutenant W. W. Morphen, USNR, in command. She was active with Service Forces, Pacific Fleet. On 27 June 1947 she was decommissioned and placed in an in-service status, continuing in the performance of her duties in various areas of the western Pacific until June 1949 when she was assigned to the 14th Naval District. In July 1950 she was reallocated to Commander, Service Forces Pacific, and in November 1955 was leased to the Republic of Korea.