On 29 June 1916 the Harwich Force was cruising off the Belgian coast when "Lightfoot" spotted a surfaced submarine and opened fire, following this up with a depth charge when the submarine dived. No German submarine was lost or damaged on this day. On 19 August 1916, the German High Seas Fleet carried out a sortie into the North Sea, planning to bombard Sunderland. The British were warned of the German operation by radio intercepts decoded by Room 40, and sailed all available forces to meet the Germans, including the Grand Fleet under Admiral Jellicoe from Scapa Flow, the Battlecruiser force under Admiral Beatty from Rosyth and the Harwich Force, including "Lightfoot". "Lightfoot" spotted the main German Fleet, but no engagement followed, with the Germans retiring rather than risking a battle with the Grand Fleet. The British light cruisers and were sunk by German submarines, while the German battleship was torpedoed and damaged by a British submarine.