Upon completion of the conversion, she rejoined the Harwich Force; on 3 July, "Engadine" and "Riviera" attempted to launch aircraft to reconnoitre the River Ems and lure out a Zeppelin so that it could be attacked. Of "Engadine"s three Sopwith Schneider floatplanes that she attempted to launch, two wrecked on takeoff and the third was badly damaged. She was transferred to Vice Admiral David Beatty's Battlecruiser Fleet (BCF), based at Rosyth in October. Later that month "Engadine" carried out trials on high-speed towing of kite balloons for gunnery observations, although she generally served as a base ship for the fleet's seaplanes.