Originally designated a "patrol gunboat", she was ordered by the United States Maritime Commission under a U.S. Navy contract as Type S2-S2-AQ1 hull number 1659 and named USS Hannam.

[citation needed] Transferred to the United Kingdom under Lend-Lease on 31 December 1943,[5] the ship was commissioned in the Royal Navy as HMS Caicos (K505) – sources claim that she was partially funded by the Turks and Caicos Islands colony, after part of which she was named[2] – on either 31 December 1943[1] or 2 January 1944.

[2] Uniquely among all World War II frigates,[1] Caicos was fitted to perform aircraft direction duties.

The Royal Navy originally intended to send her to the Indian Ocean, but instead assigned her to duty in the North Sea, where she attempted to detect German V-1 flying bombs during their flights toward targets in Great Britain.

[8] The U.S. Navy then transferred her for disposal to the U.S. Maritime Commission, which sold her in June 1946 to the N. B. Wolcott firm of New York City for scrapping.

In 1959, she participated in Operation Neptune II, and received a battle honour[12] from Vicario General Castrense and Cardenal D. Antonio Caggiano on 8 December 1960.[why?]

[14] The conversion included disarming her, installing eight specialised cabinets, nine probe basins, and a helicopter landing platform, as well as a general refit.