Sir Frederick John Owen Evans (9 March 1815 – 20 December 1885), was an officer of the Royal Navy. He became a distinguished hydrographer during his career and served as Hydrographer of the Navy. Biography Evans, son of John Evans, a master in the Royal Navy, was born on 9 March 1815. He entered the navy as a second-class volunteer in 1828. After serving in and he was transferred in 1833 to , under Captain Richard Owen, and spent three years in surveying the coasts of Central America, the Demerara River, and the Bahama Banks. Evans subsequently served in the Mediterranean on board , the flagship of the Mediterranean Fleet, and then on , , , , and , passing through the different ranks of the 'master's' line, the officers then charged with the duties of navigation. In 1841 Evans was appointed master of , and for the next five years he was employed in surveying the Coral Sea, the Great Barrier Reef of Australia, and Torres Straits. Joseph Jukes, the geologist, was on board the Fly, and wrote an account of the expedition. After a short spell of duty in the Isle of Man, Evans returned, in 1847, in , under Admiral Stokes, to New Zealand, where he was engaged for four years in surveying the Middle and South Islands. During the Crimean War he served in the Baltic Sea, receiving the special thanks of Sir Charles Napier for his share in piloting the fleet through Åland. By this time Evans had become known for his scientific abilities, and in particular for his work on magnetism. He understood the need for studies of the effects of magnetic materials on ships' compasses at a period when the Navy was being revolutionised by the shift from wooden to iron construction. He had already done considerable work on this problem in the years between 1842 and 1851. In 1855 he was appointed superintendent of the compass department of the navy, and was able to devote himself entirely to the problems of the use of the magnetic compass in iron ships and armour-clads. Evans, in co-operation with Archibald Smith, accomplished the task satisfactorily. He contributed five papers, all dealing with the magnetism of ships, to the Philosophical Transactions of the Royal Society, of which he was elected a fellow in 1862. Evans was commissioned a staff-commander in 1863, staff-captain in 1867, and full