 Promoted to commander on 3 April 1868, he was posted to the ironclad battleship HMS "Hercules" in the Channel Squadron in November 1868 and was awarded the Royal Humane Society's silver medal for jumping overboard to rescue a man who had fallen from the rigging into the River Tagus.Kerr became Flag Captain to the Commander-in-Chief, Channel Squadron and Captain of the battleship HMS "Lord Warden" in September 1871 and, having been promoted to captain on 30 November 1872 and while remaining Flag Captain to the Commander-in-Chief, Channel Squadron, he became Captain of the frigate HMS "Agincourt" in October 1874 and then Captain of the frigate HMS "Minotaur" in August 1875.He became Flag Captain to the Commander-in-Chief, Mediterranean Fleet and Captain of the frigate HMS "Inconstant" in February 1880 and then, while remaining Flag Captain to the Commander-in-Chief, Mediterranean Fleet, he became Captain of the ironclad battleship HMS "Alexandra" in March 1880.