A very large ray, sometimes called a devilfish.
(SS‑299: dp. 1,525 (surf.), 2,424 (subm.); l. 311'8"; b. 27'3"; dr. 15'8"; s. 20 k. (surf.), 8.75 k. (subm.); cpl. 81; a. 1 5", 1 40mm., 10 tt.; cl. Balao)
The second Manta (SS‑299) was laid down 15 January 1943 by the Cramp Shipbuilding Co., Philadelphia, Pa.; launched 7 November 1943; sponsored by Mrs. Michael J. Bradley; and commissioned 18 December 1944, Lt. Comdr. Edward P. Madley in command.
Upon completion of shakedown, Manta departed New London, Conn., 27 March 1945 for Hawaii via the Panama Canal and sailed from Pearl Harbor 28 May 1945 for her first war patrol, off the Kurile Islands. Returning 16 July, she began her second patrol 8 August and ended it with the cessation of hostilities 15 August. Returning to Pearl Harbor 10 September, Manta engaged in training through December. On 2 January 1946, she sailed for San Francisco and preinactivation overhaul. She was decommissioned 10 June 1946 and placed in the Pacific Reserve Fleet.
Manta recommissioned 2 August 1949, Lt. E. H. Edwards, Jr., in command, as ESS‑299. On 1 September she was redesignated AGSS‑299 and ordered to Key West, Fla. For the next 4 years she operated as a target ship for experimental antisubmarine warfare projects of Operational Development Force, Atlantic Fleet.
On 5 July 1955, Manta departed Key West for Portsmouth, N.H., to prepare for inactivation. Towed to New London, she decommissioned 6 December 1955 and was placed in the Inactive Reserve Fleet. In April 1960 she was assigned to Naval Reserve training duties with the 3d Naval District. Declared as excess to the needs of the Navy, she was struck from the Navy list 30 June 1967 and scrapped in September.