USS Fort Mandan ( LSD - 21 ) USS " Fort Mandan " ( LSD - 21 ) was a " Casa Grande " - class dock landing ship of the United States Navy , named in honor of Fort Mandan , the encampment at which the Lewis and Clark Expedition wintered in 1804 – 1805 , in what is now North Dakota . USS " Fort Mandan " ( LSD - 21 ) . " Fort Mandan " was launched on 2 June 1945 by Boston Navy Yard , Boston , Massachusetts , sponsored by Mrs . Powell M . Rhea ; and commissioned on 31 October 1945 , Lieutenant Commander W . A . Caughy , USNR , in command . 1945 – 1953 . " Fort Mandan " was assigned first to the Atlantic Reserve Fleet following her shakedown training in Chesapeake Bay , but later was assigned to duty with the Service Force , 2nd Fleet . She spent the next year in routine operations off the Atlantic coast . In April and May 1947 she participated in 8th Fleet exercises , and cruised with the United States Naval Academy and NROTC midshipmen to northern European ports during June and July . On 16 January 1948 she was placed out of commission in the Atlantic Reserve Fleet . The outbreak of the Korean War occasioned her reactivation and on 25 October 1950 , " Fort Mandan " was recommissioned , with Captain Philip D . Quirk , USN , commanding . In December she joined the Amphibious Force , Atlantic Fleet . During 1951 she engaged in Atlantic Fleet exercises through 17 May , conducted drills in the Caribbean through 29 August , and following a brief cruise in Caribbean waters underwent preparations for the " Convex " operation which occurred from 28 February to 31 March 1952 . " Fort Mandan " participated in the first NATO maneuvers , Operation Mainbrace , in August and September 1952 , and cruised with the 6th Fleet in the Mediterranean from October to January 1953 . Returning to the United States , she exercised in the Norfolk area until September when she weighed anchor to take part in Operation " Sunec " with calls at Greenland , Labrador , and Newfoundland . 1954 – 1960 . During 1954 she was overhauled at Norfolk Navy Yard , took refresher training at Narragansett Bay and another " Sunec " cruise on which she visited Baffin Island , Labrador , and Newfoundland . Two training cruises in the Caribbean in 1955 were succeeded by a third " Sunec " deployment on which she crossed the Arctic Circle for the second time . In 1956 " Fort Mandan " conducted amphibious training exercises at Vieques , Puerto Rico , and underwent overhaul at Baltimore before steaming again for the far north where she cruised in September and October . Amphibious exercises again occupied her during November 1956 and much of 1957 when she joined in " Caribex " in the Panama Canal Zone and " Narmid " 1 and 2 . From September through November 1957 she was attached to MSTS for Arctic Service , successfully transporting Army men and equipment from Greenland to Newfoundland and Virginia in a winter closing - out operation . Caribbean exercises kept her active during the first half of 1958 . In the summer months she received an overhaul at Norfolk to prepare her for more exercises in the Caribbean and a cruise to Halifax and Argentia in November . In February 1959 she joined the 6th Fleet for maneuvers in the Mediterranean where she remained until August . On 3 July , while visiting the French port of Sète , " Fort Mandan " sailors assisted local firefighters in extinguishing a fire on the Italian gasoline tanker " Ombrina " . In the fall " Fort Mandan " operated from Little Creek , Virginia , in conducting drills and exercises along the Virginia Capes area and in 1960 she again carried troops and equipment for amphibious landings in the Caribbean . Bill Cosby served in " Fort Mandan " in 1960 as a Hospital corpsman ( HM3 ) . In 1962 the ship made her film debut in " The Longest Day " , filmed as five LCM - 6 s with troops and equipment moved out of her welldeck . " Fort Mandan " received a Fleet Rehabilitation and Modernization ( FRAM II ) overhaul in 1962 . On 23 January 1971 , " Fort Mandan " was decommissioned at Norfolk , Virginia , and transferred to Greece under the Security Assistance Program . She was stricken from the Naval Vessel Register and sold to Greece on 8 February 1980 . HNS " Nafkratousa " ( L153 ) . Arriving in Greece on 30 March 1971 , the ship served in the Hellenic Navy as " Nafkratousa " ( L153 ) , replacing another " Casa Grande " ship — the former — which had operated as " Nafkratousa " ( L153 ) from 1953 until " Fort Mandan " s acquisition . The former " Fort Mandan " was decommissioned by the Hellenic Navy on 29 February 2000 , and sold for scrap in November 2001 , to be dismantled at Aliağa , Turkey .