 On the morning of 28 August , Cöln was re @-@ coaling in Wilhelmshaven . Her sister , Mainz , was at anchor in the mouth of the Ems , and Ariadne lay in the entrance to the Weser . These three cruisers were assigned to support the cruisers Stettin and Frauenlob , and the aviso Hela , which were stationed on the patrol line that morning . At 07 : 57 , the Harwich Force encountered the outer German torpedo boats , which fled back to the German cruisers on the patrol line . In the ensuing Battle of Heligoland Bight , Stettin engaged the British force first , and was quickly reinforced by Frauenlob . Upon receiving reports of the action , Rear Admiral Franz von Hipper , the commander of the reconnaissance forces , ordered Maass to deploy his cruisers to support the engaged vessels . At 09 : 30 , Cöln steamed out of port . 
