HMS Niger was an 8-gun (later 14-gun) screw sloop launched on 18 November 1846 from Woolwich Dockyard. She had been intended as a sailing sloop but her design was lengthened to fit a steam engine, and she was fitted with screw propulsion at Deptford Dockyard in 1847-48 prior to completion. She was reclassified as a corvette in 1852. She conducted important propulsion trials, finally proving the superiority of screw propulsion and served in West Africa, the Crimea, China, the East Indies and Australia. She took part in the New Zealand wars in 1860 and was sold for breaking in 1869.