HMS Neptune ( 1874 ) HMS " Neptune " was an ironclad turret ship originally designed and built in Britain for Brazil , but acquired for the Royal Navy in 1878 . Modifications to suit the Royal Navy took three years to complete and the ship did not begin her first commission until 1883 with the Channel Fleet . She was transferred to the Mediterranean Fleet in 1885 , but refitted in Portsmouth in 1886 – 87 . " Neptune " then became the coastguard ship for the 1st Class Reserve at Holyhead until 1893 when she was placed in reserve in Portsmouth . While she was being towed to the breakers in 1903 , " Neptune " unintentionally rammed , then serving as a training hulk for the Naval Signal School , collided with , and narrowly missed several other ships . She was scrapped in Germany in 1904 . Design and description . HMS " Neptune " was designed by Sir Edward Reed for the Brazilian Navy in 1872 as a masted version of , a larger , sea - going version of the breastwork monitor s , and was given the provisional name " Independencia " . Adding masts , however , meant adding a forecastle at the bow and a poop deck at the stern to provide the space required for the masts and rigging . These blocked the firing arcs of the gun turret s so that they were deprived of the axial fire which was the original design ' s greatest virtue . The ship resembled , instead , an enlarged version of . During the Russo - Turkish War of 1877 – 78 tensions dramatically escalated between Russia and Great Britain as the latter feared that the victorious Russian armies would occupy the Turkish capital of Constantinople , something that the British were not prepared to tolerate . They mobilized much of the Royal Navy in case war did break out and purchased a number of ironclads under construction , including " Independencia " , in 1878 . The Brazilians sold the ship for £600 , 000 , nearly twice as much as the £370 , 000 paid for " Devastation " a few years earlier . Another £89 , 172 was spent to bring her up to the standards of the Royal Navy . In British service she was deemed " a white elephant , being a thoroughly bad ship in most respects — unlucky , full of inherent faults and small vices , and at times a danger to her own consorts " . HMS " Neptune " was long between perpendiculars . She had a beam of and a draft of . The ship normally displaced and at deep load . " Neptune " proved a poor seakeeper as she was wet , difficult to manoeuvre and a heavy roller . She had a skylight over the wardroom , which as a result often flooded while the ship was at sea . Propulsion . " Neptune " had one 2 - cylinder trunk steam engine , made by John Penn and Sons , driving a single propeller . Eight rectangular boilers provided steam to the engine at a working pressure of . The engine had a total designed output of , but produced a total of during sea trials in February 1878 which gave " Neptune " a maximum speed of . The ship carried of coal , enough to steam at even though Sir George Tryon described her as " a weak ship in her engines and consuming a coal - mine daily " . " Neptune " was barque - rigged , but her twin funnels were so close to the mainmast that the sails and rigging rapidly deteriorated in service . The mast was eventually stripped of sails and yard s so that the ship only used the fore and mizzen masts ; an unsightly combination described as " like a half - dressed harlot " . During her 1886 refit the ship ' s masts and rigging were replaced by simple pole masts with fighting tops at the fore and mizzen positions only . Armament . The Brazilians had ordered four Whitworth for the gun turret s and a pair of breech - loading guns as chase gun s , but these were replaced in British service . HMS " Neptune " mounted a pair of muzzle - loading rifles in each turret and two rifled muzzle - loading guns in the forecastle as chase guns . These guns only traverse 45° to the side . The ship also had six 20 - pounder Armstrong guns for use as saluting guns . Two torpedo tubes were mounted on the main deck , one on each side , for Whitehead torpedo s . The shell of the 16 - calibre 12 . 5 - inch gun weighed while the gun itself weighed . It had a muzzle velocity of and was credited with the ability to penetrate a nominal of wrought iron armour at the muzzle . The 14 - calibre 9 - inch gun weighed and fired a shell at a muzzle velocity of . It was credited with the nominal ability to penetrate armour . The muzzle blast of the main guns was more than the deck immediately below the muzzles could stand and the full charge for the guns was reduced from of powder to minimize the damage . Armour . " Neptune " had a complete waterline belt of wrought iron that was thick amidships and thinned to and then to in steps at the ends of the ship . The armour extended above the waterline and below it . An armoured citadel long protected the bases of the gun turret s , the funnel uptakes and the ventilation shafts for the engines and boilers . The sides of the citadel were 10 inches thick and it was closed off by transverse bulkheads thick . The chase guns at the bow were protected by a patch of armour . The faces of the turrets were thick while the sides were thick . They were backed by of teak . The armoured deck was outside the citadel and 2 inches thick inside it . " Neptune " was provided with an conning tower protected by 6 – 8 inches of armour situated right in front of the foremast . It could " be regarded as the first adequately installed conning position installed in a British " ironclad . Service . HMS " Neptune " was laid down in 1873 for the Brazilian Navy under the name of " Independencia " by J & W Dudgeon in Cubitt Town , London . The shipyard attempted to launch her on 16 July 1874 , but she stuck fast and did not budge . A second attempt was made on 30 July during which the ship got about one - third down the slipway and stuck , extensively damaging her bottom plating . She was finally launched on 10 September , after she had been lightened , and she was towed to Samuda Brothers for repairs and fitting out . The cost of the accident resulted in the bankruptcy of Dudgeons in 1875 . " Independencia " ran her sea trials in December 1877 and purchased by the Royal Navy in March 1878 and renamed " Neptune " , after the Roman god of the sea . She was then taken to Portsmouth for alterations to her armament and other equipment that took until 3 September 1881 to complete . " Neptune " was commissioned on 28 March 1883 for service with the Channel Fleet . She was transferred to the Mediterranean Fleet in 1885 , but returned to Portsmouth in July 1886 for a refit . The ship was assigned as the guard ship for the 1st Class Reserve at Holyhead in May 1887 . " Neptune " paid off into reserve in November 1893 in Portsmouth . The ship was sold for £18 , 000 on 15 September 1903 for scrap . While under tow by the tug " Rowland " and another at her side out of Portsmouth on 23 October 1903 , " Neptune " broke the cables connecting her to the tugs in a storm . With the winds and a strong flood tide pushing her , she was pushed back into the harbour and narrowly missed the training ship for Osborne College , . " Neptune " struck the training brig " Sunflower " anchored beside " Racer " a glancing blow and then hit the port side of , making a hole at her orlop deck . " Neptune " then was pushed by the tides and winds toward and came to rest against the bow ram of " Hero " . She was finally broken up in Lemwerder , Germany , in 1904 .