HMS Melampus was a 46-gun modified fifth-rate frigate built for the Royal Navy during the 1810s. Completed in 1820, she was not commissioned until 1845 for the South America Station and was converted into a store and receiving ship in 1855. The ship was briefly assigned as a coast guard ship before being paid off in 1858. Melampus was converted into a Roman Catholic chapel ship in 1866 and then became a store ship twenty years later. The ship was sold for scrap in 1906.
Melampus had a length at the gundeck of and at the keel. She had a beam of , a draught of and a depth of hold of . The ship's tonnage was 1088 <small></small> tons burthen. The modified Leda-class frigates were armed with twenty-eight 18-pounder cannon on her gundeck, fourteen 32-pounder carronades on her quarterdeck and a pair of 9-pounder cannon and two more 32-pounder carronades in forecastle. The ship had a crew of 315 officers and ratings.
Melampus, the second ship of her name to serve in the Royal Navy, was ordered on 1 May 1816, laid down in August 1817 at Pembroke Dockyard, Wales, and launched on 10 August 1820. She was completed for ordinary at Plymouth Dockyard 2âÂÂ23 September 1829 and was roofed over from the mainmast forward. The ship cost ã23,007 to build and ã7,072 to fit out for ordinary. She was fitted out for sea at a total cost of ã9,156 from March to 18 May 1845.
Melampuss first commission began on 12 March with Captain John Campbell in command and she was ready for sea on 18 May.