German FK cruiser designs The German Imperial Navy ( " Kaiserliche Marine " ) created a series of fleet cruiser designs — designated " Flottenkreuzer " — in 1916 to follow the s ordered in 1915 . They were initially intended to favor high speed for reconnaissance over the heavier gun armament of the " Cöln " class , though by the final iterations , they were as powerful as the earlier class . The design staff ultimately drew up five different designs : FK 1 , FK 1a , FK 2 , FK 3 , and FK 4 . The proposals ranged in size from to designed displacement and were armed with a main battery of between five and eight guns . Each proposed design grew in size over the preceding draft , as the weaponry and propulsion systems were increased . None of the designs were built , owing to shifting construction priorities in the German Navy in the last year of World War I . FK 1 and FK 1a . By 1916 , thirteen German light cruiser s had been lost in the course of World War I . To replace them , the " Kaiserliche Marine " ordered ten new cruisers of the . The next design , under the provisional name FK 1 , or " Flottenkreuzer " ( Fleet cruiser ) , was prepared in 1916 . The design , which emphasized the reconnaissance role and high speed over combat power , was based on the British s at the request of Kaiser Wilhelm II . A modified design , named FK 1a , was a slightly larger vessel . FK 1 was long at the waterline and long overall . The design had a beam of ; its forward draft was and the aft draft was . The ship would have had a double bottom of approximately 52 percent of the length of the hull , and fifteen watertight compartments . The hull was constructed with longitudinal steel frames . As designed , the ship would have had a displacement of , with a full load combat displacement of . The modified FK 1a was slightly larger , at long at the waterline and long overall . The modified design had a beam of and a draft of . The ship ' s hull would have been constructed as in FK 1 , with the same number of watertight compartments and extent of double bottom . As designed , the ship would have had a displacement of , with a full load combat displacement of . Both designs would have been powered by two sets of Marine - type steam turbines that each drove a three - bladed screw wide in diameter . FK 1 would have been equipped with five Marine - type oil - fired watertube boiler s , while FK 1a would have had improved double - ended models . The propulsion system of FK 1 was rated at a maximum of for a top speed of . The improved engines of FK 1a were rated at and a maximum speed of . The designs carried up to and of fuel oil , respectively , which permitted a cruising radius of at a speed of . Both designs were equipped with three diesel generators that produced at 220 volts . Steering was controlled by a single rudder . The armament of both designs consisted of five 15 cm SK L / 45 guns in single mounts , one forward , two abreast of the conning tower , and two in a superfiring pair aft of the rear superstructure . The 15 cm gun fired a shells at a muzzle velocity of . FK 1 and FK 1a were supplied with 500 and 650 shells for their main batteries , respectively . The guns had a range of . Both designs were equipped with a pair of 8 . 8 cm SK L / 45 anti - aircraft guns , mounted on the centerline amidships . The guns were equipped with 100 rounds of ammunition each . These guns fired a shells . Both ships would have carried four torpedo tube s mounted on the deck in swivel launchers . FK 1a was also equipped with 100 mines . Both designs called for a crew of 15 officers and 342 enlisted men . FK 2 , FK 3 , and FK 4 . Over the course of the design process that continued through 1916 , the size of the projected cruisers increased as the navy added new design requirements . This resulted in the FK 2 design . The length increased to overall and at the waterline . Their beam increased to , as did their draft , to . Their displacement correspondingly rose to at normal load and at combat load , significantly greater than the original design . The FK 2 design was armed with five 15 cm SK L / 45 guns and two 8 . 8 cm SK L / 45 anti - aircraft guns . It was to carry the same 60 cm torpedo tubes in twin mounts as the earlier designs . The design retained the same propulsion system as the earlier designs , but with an improved engine type and an additional boiler , which produced an estimated for a top speed of 32 knots . Range was to have been 2 , 800 miles at 17 knots , as in the original design . The next iteration , FK 3 , brought even more increases . Displacement rose to normal and full load , double that of the original FK design . Length was at the waterline and overall , and the beam was . The armament was also augmented by an additional two 15 cm and 1 8 . 8 cm gun . Since the size of the ship had increased , a more powerful propulsion system was necessary ; a third set of turbines was added , and the number of boilers was increased to thirteen . This produced , for the same speed and range figures as in the previous designs . The final design , FK 4 , was larger still . The standard displacement was , and at combat load , this rose to . The projected cruiser would have been long at the waterline , with a beam of and a draft of . The armament was increased again , with an additional 15 cm gun . The ship ' s propulsion system would have included six coal - fired boilers and nine oil - fired models . Ultimately , none of these designs were ever built , much like other late - war German warship designs , such as the L 20 α - type battleships and the s . The German shipbuilding effort largely abandoned surface warship construction and instead focused on U - boat construction in the final years of the war .