Upon completion of the modifications on 1 September, "Engadine" was assigned to the Harwich Force along with the seaplane tenders and . On Christmas Day 1914, nine aircraft from all three ships took part in the Cuxhaven Raid on hangars housing Zeppelin airships. Seven of the nine seaplanes successfully took off for the attack, but they inflicted little damage. Only three of the aircraft returned to be recovered, but the crews of the other three ditched safely and were recovered by a British submarine and the Dutch trawler "Marta van Hattem". A notable member of her crew was Robert Erskine Childers who served as an instructor in coastal navigation to newly trained pilots. He managed to extend his duties to include flying as a navigator and observer and participated in the raid, for which he was mentioned in despatches.