USS Thetis Bay (CVE-90) was the thirty-sixth of fifty Casablanca-class escort carriers built for the United States Navy during World War II.

She was reactivated in July 1956, and converted to a helicopter transport carrier, serving in relief operations in Taiwan and Haiti.

She was powered with two Skinner Unaflow reciprocating steam engines, which drove two shafts, providing 9,000 horsepower (6,700 kW), thus enabling her to make 19 knots (35 km/h; 22 mph).

She had a designed complement of 900 crew and 938 troops, was armed with four twin 40 mm (1.6 in) anti-aircraft guns, and carried twenty helicopters.

[5][1] Her construction was awarded to Kaiser Shipbuilding Company, Vancouver, Washington, under a United States Maritime Commission contract, on 18 June 1942.

[2][9][10] Upon being commissioned, Thetis Bay underwent a shakedown cruise down the West Coast to San Diego, California.

She steamed into port on 13 July, and after unloading her cargo, headed for Terminal Island, Los Angeles for a three-week overhaul.

[9] On 12 June, Thetis Bay steamed into Pearl Harbor carrying a load of aircraft, having departed from San Diego.

[9] Upon finishing her replenishment mission, Thetis Bay returned to the United States via Guam, arriving at Alameda on 7 September.

[9] In May 1955, Thetis Bay was withdrawn from the Pacific Reserve Fleet and towed to the San Francisco Naval Shipyard under project SCB 122, where she began conversion into the Navy's first assault helicopter aircraft carrier.

She then participated in amphibious training exercises off of the California coast, evaluating her planned complementary role, before deploying to the Far East on 10 July 1957.

Thus, Thetis Bay, which was serving with the Seventh Fleet at the time, was dispatched from Hong Kong on 12 August, proceeding to Taiwan to conduct relief operations.

This practice operation represented the first large-scale night landing of ground forces by helicopters based on board a carrier.

She deployed to the western Pacific for the spring of 1961, and upon completing her tour and returning to Long Beach, she was transferred to the United States Atlantic Fleet.

In October 1962, during the height of the Cuban Missile Crisis, she proceeded into the naval "quarantine" area along with her helicopter contingent and a marine landing team, standing by for potential actions.

In the spring of 1963, she ferried special aircraft required for President John F. Kennedy's planned visit to West Germany to Hamburg.

She was struck from the Naval Vessel Register on 1 March 1964, and she was sold for scrapping in December 1964 to Peck Iron & Metal Co., Inc., headquartered at Portsmouth, Virginia.