The four ships were taken over by Germany for incorporation into the Kaiserliche Marine (German Navy) while still under construction on 10 August 1914 owing to the outbreak of the First World War, with Z4 being renamed SMS V108.

[3] 60 tonnes (59 long tons) of coal and 16.2 tonnes (15.9 long tons) of oil were carried, giving a range of 1,400 nautical miles (2,600 km; 1,600 mi) at 17 knots (31 km/h; 20 mph) or 460 nautical miles (850 km; 530 mi) at 20 knots (37 km/h; 23 mph).

[8] From 3 to 5 June 1915, German naval forces, including V108 carried out an attempted penetration of the Irben Strait with the intention of mining the southern entrance to the Moon Sound, while the seaplane carrier Glyndwr's aircraft would attack a factory near Daugavgrīva.

The presence of large numbers of Russian warships (including 16 destroyers and torpedo boats) resulted in the operation being abandoned, but on the return journey to Libau, Glyndwr ran into a previously undiscovered Russian minefield off Windau on 4 June, striking one mine, which badly damaged the seaplane carrier, causing serious flooding.

[13] In June 1919, Treaty of Versailles required that the German Navy surrender most of its remaining warships for division between the victorious powers.

[16][17] On 20 July 1925, a boiler explosion wrecked Kaszub while in dock in Danzig, with the forward part of the ship sinking.