HMS Hermes was a Highflyer-class protected cruiser built for the Royal Navy in the 1890s. She spent much of her early career as flagship for various foreign stations before returning home in 1913 to be assigned to the reserve Third Fleet. The ship was modified later that year as the first experimental seaplane carrier in the Royal Navy. In that year's annual fleet manoeuvers, she was used to evaluate how aircraft could cooperate with the fleet and if aircraft could be operated successfully at sea for an extended time. The trials were a success and Hermes was paid off in December at their conclusion. She was recommissioned at the beginning of World War I in August 1914 for service as an aircraft ferry and depot ship for the Royal Naval Air Service. She was torpedoed and sunk by a German su