 After her commissioning in 1909 , Mainz served with the reconnaissance forces of the German fleet . Her first commander was Fregattenkapitän ( commander ) Friedrich Tiesmeyer , the uncle of Ernst Lindemann ; he held the command until January 1910 . She was assigned to the II Scouting Group , which screened for the battlecruisers of the I Scouting Group . After the outbreak of World War I at the beginning of August 1914 , she and several other cruisers were tasked with patrol duties in the Heligoland Bight . The cruisers were divided with the torpedo boat flotillas , and assigned to rotate through nightly patrols into the North Sea . As part of this operation , Mainz conducted a patrol on the night of 16 August with the VIII Torpedo @-@ boat Flotilla , without incident . 
