See main article: Commencement Bay-class escort carrier.
In 1941, as United States participation in World War II became increasingly likely, the US Navy embarked on a construction program for escort carriers, which were converted from transport ships of various types. Many of the escort carrier types were converted from C3-type transports, but the s were instead rebuilt oil tankers. These proved to be very successful ships, and the, authorized for Fiscal Year 1944, were an improved version of the Sangamon design. The new ships were faster, had improved aviation facilities, and had better internal compartmentation. They proved to be the most successful of the escort carriers, and the only class to be retained in active service after the war, since they were large enough to operate newer aircraft.
Commencement Bay was long overall, with a beam of at the waterline, which extended to at maximum. She displaced 21397LT at full load, of which could be fuel oil (though some of her storage tanks were converted to permanently store seawater for ballast), and at full load she had a draft of . The ship's superstructure consisted of a small island. She had a complement of 1,066 officers and enlisted men.
The ship was powered by two Allis-Chalmers geared steam turbines, each driving one screw propeller, using steam provided by four Combustion Engineering-manufactured water-tube boilers. The propulsion system was rated to produce a total of for a top speed of 19kn. Given the very large storage capacity for oil, the ships of the Commencement Bay class could steam for some 23900nmi at a speed of .
Her defensive anti-aircraft armament consisted of two dual-purpose guns in single mounts, thirty-six Bofors guns, and twenty Oerlikon light AA cannons. The Bofors guns were placed in three quadruple and twelve twin mounts, while the Oerlikon guns were all mounted individually. She carried 33 planes, which could be launched from two aircraft catapults. Two elevators transferred aircraft from the hangar to the flight deck.
The first fifteen ships of the Commencement Bay class were ordered on 23 January 1943, allocated to Fiscal Year 1944. The first ship of the class was laid down on 23 September 1943 at the Todd Pacific Shipyards in Tacoma, Washington, originally under the name St. Joseph Bay. She was renamed Commencement Bay during construction, after the nearby Commencement Bay in Puget Sound. On 9 May 1944, the ship was launched, and after completing fitting out work, was commissioned into active service on 27 November.
On 1 February 1945, Commencement Bay moved to Seattle, Washington, where she began her active career as a training ship. She operated in this role in Puget Sound for the next nine months, during which time she trained some 545 officers and 5,053 enlisted men who went on to serve aboard Commencement Bays sister ships as they were completed at the Todd Pacific facilities. She also qualified 249 pilots from eight air groups for carrier operations. On 21 October, she departed Bremerton, Washington, bound for Pearl Harbor, Hawaii, arriving there on 4 November. She spent the next three weeks participating in carrier qualification training, and on 27 November, departed to return to Seattle. She then moved on to Tacoma soon thereafter.
Over the course of the following months, Commencement Bay sailed south to visit Los Angeles and San Pedro, California, before returning to Tacoma on 28 January. She was decommissioned there on 30 November 1946 and allocated to the Pacific Reserve Fleet. Ten of the Commencement Bay-class ships saw significant service postwar as anti-submarine warfare carriers, but they were small and had difficulty operating the new Grumman AF Guardian patrol planes, so they were soon replaced by much larger s. She saw no further service, but was reclassified as a helicopter carrier with the hull number CVHE-105 on 12 June 1955. On 7 May 1959, she was reclassified again, now as an aircraft ferry with the hull number AKV-37. She lingered on in the Navy's inventory until 1 April 1971, when she was struck from the Naval Vessel Register. She was eventually sold to ship breakers on 25 August 1972 and subsequently scrapped.