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.

To replace them, the Kaiserliche Marine ordered ten new cruisers of the Cöln class.

The design, which emphasized the reconnaissance role and high speed over combat power, was based on the British C-class cruisers at the request of Kaiser Wilhelm II.

The ship would have had a double bottom of approximately 52 percent of the length of the hull, and fifteen watertight compartments.

The ship's hull would have been constructed as in FK 1, with the same number of watertight compartments and extent of double bottom.

[2] Both designs would have been powered by two sets of Marine-type steam turbines that each drove a three-bladed screw 3.5 m (11 ft) wide in diameter.

The propulsion system of FK 1 was rated at a maximum of 48,000 shaft horsepower (36,000 kW) for a top speed of 32 knots (59 km/h; 37 mph).

The improved engines of FK 1a were rated at 52,000 shp (39,000 kW) and a maximum speed of 33 kn (61 km/h; 38 mph).

[2] 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.

Both designs were equipped with a pair of 8.8 cm SK L/45 anti-aircraft guns, mounted on the centerline amidships.

[4] Both ships would have carried four 60 cm (24 in) torpedo tubes mounted on the deck in swivel launchers.