Köln (F220) was a West German frigate, and name ship of her class. Laid down 21 December, 1957, she was the first ship in the world to feature combined diesel and gas propulsion (CODAG), which allowed for the longer cruise ranges of diesel fuel, with the higher sprint speeds of gas turbines. Her weapons wouldn't have seemed out of place in World War II: a pair of 100mm guns, twin and single 40mm AA guns, four 533mm torpedo tubes, and a pair of quadruple 375mm anti-submarine mortars. She also continued the German favorite of having their escorts be able to double as mine layers, by swapping out their complement of depth charges. Köln commissioned 15 April, 1961, and remained in service until 1982. She was used as a hulk until 2016, when she was broken up.