Xanthus - class repair ship The " Xanthus " class repair ships were a class of five auxiliary ships built for the United States Navy and Royal Navy . Ships of the class served in a diverse range of environments in varying capacities during both World War II and the Korean War . " Xanthus " class ships were in commission between 1945 – 1955 . Description . On 26 February 1944 , the United States CNO FADM Ernest J . King authorized the construction of five vessels in response to a British Royal Navy request for several Heavy Duty Fleet Repair Ships . These ships were to have been constructed in the United States and later transferred to Britain under the Lend - Lease agreement . Design and Construction . " Xanthus " class vessels were first laid down in mid - 1944 by Bethlehem - Fairfield Shipyard under a Maritime Commission contract . These ships were originally intended as Liberty ship s , hull design EC2 - S - C1 ( which , at the time , were also under construction for Britain ) . Instead , five of the partially completed Liberty ship hulls were requisitioned for conversion into repair ships . It was soon realized that the Liberty ship hull and configuration would not be suitable for the role of repair ship . Substantial modification was necessary in order to ensure operating efficiency and functionality . A planning commission investigating the problem decided that the modifications would be based off the design of Luzon class repair ship s , ARG type repair ships which had already seen substantial service in the Pacific . Construction proceeded , with initial hull alterations and armament based off the " Luzon " class . The " Luzon " repair ship USS " Tutuila " ( ARG - 4 ) was selected as the conversion template . It was quickly realized that conversion based ultimately off the " Luzon " would not be entirely successful , because British configuration requirements for the ships differed substantially from the " Luzon " design . A complete overhaul of the internal configuration , and thus completely new plans for the internal configuration , were necessary . Each remained in Bethlehem - Fairfield Shipyard for most of the construction process . At approximately 80 % completion , the ships were transferred to the conversion docks . Four of the five ships remained in Maryland and were converted by the Maryland Drydock Company . The other ship , AR - 19 , was sent to Bethlehem - Simpson Yard in Boston , Massachusetts . While all five ships were intended for the Royal Navy , only two were delivered . The other three were expropriated by the US Navy sometime prior to completion and were given the " Xanthus " class designation . Operational history . " Xanthus " class vessels provided a diverse range of auxiliary repair functions for both the US and British navies . American - flagged ships served in the Pacific with the US Navy , repairing ships damaged in the final battles against Japan . These ships continued their role after the war by providing support for the Allied occupation of Japan . British flagged ships served in the Atlantic with the Royal Navy repairing both aircraft and destroyers before being returned to the United States shortly following the war ' s end . One ship , USS " Laertes " , also served in the Korean War . HMS " Assistance " ( AR - 17 ) / ( F - 173 ) . HMS " Assistance " was laid down in May 1944 and delivered to the Royal Navy on 20 January 1945 . The ship served in British home waters as an aircraft depot and repair ship . She was returned to US Navy and transferred to the National Defense Reserve Fleet in 1946 . HMS " Diligence " ( AR - 18 ) / ( F - 174 ) . HMS " Diligence " was laid down in June 1944 and transferred to Britain in 1945 . She served as a destroyer repair vessel until returning to US Navy in 1946 . She was subsequently transferred to National Defense Reserve Fleet . USS " Xanthus " ( AR - 19 ) . USS " Xanthus " was laid down in June 1944 , launched in July and finally commissioned in May 1945 . She arrived at Pearl Harbor on 20 July 1945 and briefly served in the repair role . On 11 August , " Xanthus " sailed for Alaska , where she was to join forces massing for the planned assault on the Japanese held Kuril Islands . The invasion never took place , and instead " Xanthus " was sent to Japan where she served as the flagship of Task Group 56 . 2 . " Xanthus " later operated out of Okinawa until January 1946 . In February 1946 , " Xanthus " sailed for China where she supported American naval activities . She was withdrawn in April of that year and sent to the National Defense Reserve Fleet in James River , Virginia . USS " Laertes " ( AR - 20 ) . USS " Laertes " was laid down in August 1944 , launched in September and commissioned in March 1945 . She was sent to the naval facilities at Enewetak Atoll , where she spent four months repairing battle damaged ships . From there she sailed to Okinawa , where she spent only a week before setting course for the United States . " Laertes " served several months as a preinactivation repair ship in Bremerton , Washington and San Diego , California before being decommissioned and entering the Pacific Reserve Fleet . " Laertes " was recommissioned on 19 December 1951 in response to the outbreak of hostilities in Korea . She operated from the Japanese port of Sasebo and the Korean port of Pusan repairing the battle damaged ships of the United States Seventh Fleet . USS " Dionysus " ( AR - 21 ) . USS " Dionysus " was laid down in September 1944 , launched in October and commissioned in April 1945 . She operated from Enewetak Atoll and Tokyo Bay between July and September 1945 . She was recommissioned in 1952 and joined the Atlantic Fleet , where she repaired ships in Puerto Rico and in ports along the Eastern United States . Trivia . The class and the lead ship were named after Xanthus , one of Achilles ' horses who spoke with a human voice .