Laid down under Maritime Commission contract (MC hull 745) as Marine Dolphin on 20 August 1943.
Re-named Tranquility on 22 June and launched on 25 July. Acquired by the Navy from the Maritime Commission on 14 August and converted into a hospital ship.
Commissioned on 24 April 1945 and departed Norfolk on 6 June bound for Hawaii. Transited the Panama Canal on 14 June and arrived at Pearl Harbor on the 27th to join the Service Force, Pacific Fleet. On 11 July, Tranquillity proceeded to Ulithi to serve as the base hospital ship from 22 July to 3 August. On 3 August, she was sent to the Palaus to embark the survivors from cruiser Indianapolis (CA-35) which was sunk by a Japanese submarine several days earlier. She arrived at Peleliu the next morning; embarked 166 survivors; and headed for Guam where the patients were disembarked on the 8 August. Tranquility returned to Ulithi on 10 August but was then ordered to sea the next day to rendezvous with the 3rd Fleet some 350 miles off the coast of Japan. Following a fortnight with the 3d Fleet, the hospital ship headed for Guam. On the 27 August, she took on 766 patients at Apra Harbor and embarked for the United States. She disembarked the patients at San Francisco on 11 September and then returned to Hawaii, arriving at Pearl Harbor on the 26th. She was attached to the "Magic-Carpet" Fleet, returning armed forces personnel from overseas bases to the United States. The ship arrived at Guam on 18 October, picked up 788 patients, and disembarked them at San Francisco on 3 November. On 9 November, the ship was reclassified as a hospital transport and redesignated APH-114. The ship made two more voyages with the "Magic-Carpet" Fleet and returned to San Francisco on 30 January 1946.
Tranquility sailed for the east coast on 18 February and arrived at Philadelphia on 22 March. Three days later, she was redesignated AH-14. Tranquility was placed out of commission, in reserve, on 26 July. Struck from the Navy list on 1 September 1961.
These specifications and ship histories are adapted from the Dictionary of American Naval Fighting Ships (US Naval Historical Center) and from various other sources. These summaries may not reflect the most recent information concerning the ships' status or operations. If you find an error or discrepancy, please email me at firstname.lastname@example.org or fill out our online crossing submission form.