Rosario - class sloop The " Rosario " class was a class of seven screw - sloops of wooden construction built for the Royal Navy between 1860 and 1862 . A further six vessels were ordered and laid down , but were cancelled in 1863 before launch . This was the last class of purely wooden sloops built for the Royal Navy . Design . The " Rosario " class were designed in 1858 by Issac Watts , the Director of Naval Construction . They were built of wood , were rated for 11 guns and were built with a full ship rig of sails ( this was reduced to a barque rig by about 1869 ) . With a length overall of and a beam of , they had a displacement of 913 tonnes . These were the last sloops constructed for the Royal Navy to retain all - wooden construction ; their successors , the " Amazon " class , incorporated iron cross beams . Propulsion . All the completed vessels , with the exception of " Shearwater " , were fitted with a Greenock Foundry Company two - cylinder horizontal single - expansion steam engine driving a single screw . With an indicated horsepower of between and they were capable of about under steam . " Shearwater " s R & W Hawthorn engine was similar in design and power . Armament . As designed , ships of the class carried a single slide - mounted 40 - pounder Armstrong breech - loading gun , six 32 - pounder muzzle - loading smooth - bore guns and four pivot - mounted 20 - pounder Armstrong breech loaders . By 1869 the armament had been reduced to a single muzzle - loading gun and two 40 - pounders . Operational lives . " Rosario " . " Rosario " served a four - year commission on the North America and West Indies Station and then served an eight - year commission in Australia . She paid off in Sheerness in 1875 and was broken up nearly ten years later . " Peterel " . " Peterel " served three commissions as a warship , on the North America and West Indies Station , the Cape of Good Hope Station and the Pacific Station . In 1877 she became a lightship marking the wreck of " Vanguard " , then in 1885 she was converted into a coal depot before finally being sold in 1901 , the longest lived of her class . " Rapid " . " Rapid " served a commission on the Cape of Good Hope Station and then two commissions with the Mediterranean Fleet before being broken up at Malta after more than 20 years service . " Shearwater " . " Shearwater " spent a single six - year commission on the Pacific Station and was then converted into a survey vessel . Under George Strong Nares and later William Wharton ( later Hydrographer of the Navy ) she surveyed around the Mediterranean and the East coast of Africa . She was broken up at Sheerness in 1877 . " Royalist " . " Royalist " served both her commissions on the North America and West Indies Station , being commanded between 1865 and 1866 by Maurice Horatio Nelson , son of Thomas Nelson , 2nd Earl Nelson and great nephew to Horatio Nelson . She was broken up at Chatham in 1875 . " Columbine " . " Columbine " served briefly in the Channel Squadron before moving to the Pacific Station . Her second commission was on the East Indies Station , which at the time was involved in a long campaign to combat slavery in the area . Like " Royalist " , she was broken up at Chatham in 1875 . " Africa " . Of all the class , " Africa " had by far the shortest career in the Royal Navy , but one of the most unusual . Sold to the Imperial Chinese Customs shortly after launch , and renamed " China " , she became part of Sherard Osborn ' s " Vampire Fleet " , along with " Jasper " and " Mohawk " . The venture came to nothing when it became apparent that command would not rest with the Emperor , but instead with local Mandarins . Osborn resigned his command , and the ships were resold to the Egyptian government in the mid - 1860s .