This cruiser design was born soon after the outbreak of the war. Several sets of turbines, which had been ordered for the projected Russian battlecruiser Navarin, were nearing completion when they were seized by the German government. This made it possible to build a special kind of fast hybrid cruiser, a mixture between mine laying ship and small cruiser. With the turbines almost complete, planning and building time could be kept short, so both ships could enter fleet service in 1916. To achieve maximum speed, the boilers were mostly oil fired, whereas most other German cruisers used a mixture of coal and oil firing. With mines as the main armament, the artillery complement was reduced to four 15cm guns to conserve weight, and the armour protection was reduced to about half the usual stre