Cooper Key was transferred to a special squadron operating in the Channel formed to combat fears of war with Russia. Fisher went with him as flag captain of HMS "Hercules" from 7 June to 21 August 1878. From 22 August to 12 September he transferred still as flag captain under Cooper Key to . At this time Fisher first became a proponent of the new compass being designed by Sir William Thomson which incorporated corrections for the deviation caused by the metal in iron ships.