HMS Northumberland ( 1866 ) HMS " Northumberland " was the last of the three armoured frigate s built for the Royal Navy during the 1860s . She had a different armour scheme and heavier armament than her sister ships , and was generally regarded as a half - sister to the other ships of the class . The ship spent her career with the Channel Fleet and occasionally served as a flagship . " Northumberland " was placed in reserve in 1890 and became a training ship in 1898 . She was converted into a coal hulk in 1909 and sold in 1927 , although the ship was not scrapped until 1935 . Design and description . The " Minotaur " - class armoured frigates were essentially enlarged versions of the ironclad with heavier armament , armour , and more powerful engines . They retained the broadside ironclad layout of their predecessor , but their sides were fully armoured to protect the 50 guns they were designed to carry . Their plough - shaped ram was also more prominent than that of " Achilles " . " Northumberland " was long between perpendiculars and had a beam of and a draught of . The ship displaced and had a tonnage of 6 , 621 tons burthen . Her hull was subdivided by 15 watertight transverse bulkheads and had a double bottom underneath the engine and boiler rooms . The ship was considered " a steady gun platform , able to maintain her speed in a seaway and satisfactory in manoeuvre " . She was authorized a crew of 705 officers and enlisted men , but actually carried 800 men . Propulsion . " Northumberland " had a two - cylinder trunk steam engine , made by John Penn and Sons , driving a single propeller using steam provided by 10 rectangular fire - tube boiler s . It produced a total of during the ship ' s sea trials on 15 September 1868 and " Northumberland " had a maximum speed of . The ships normally carried of coal , but had a maximum capacity of , enough to steam at . Originally designed with three masts , " Northumberland " was fitted with five masts until her 1875 – 79 refit when two were removed and she was re - rigged as a barque . " Northumberland " only made under sail , mainly because the ship ' s propeller could only be disconnected and not hoisted up into the stern of the ship to reduce drag , the worst speed of any ironclad of her era . Admiral George A . Ballard described the " Minotaur " - class ships as " the dullest performers under canvas of the whole masted fleet of their day , and no ships ever carried so much dress to so little purpose . " Armament . Unlike her half - sisters , " Northumberland " was armed with a mix of , , and rifled muzzle - loading guns . All 4 nine - inch and 18 eight - inch were mounted on the main deck while 4 eight - inch guns were fitted on the upper deck as chase gun s . Both seven - inch guns were mounted in the stern on the main deck , also as chase guns . The nine - inch gun was credited with the ability to penetrate of wrought iron armour at the muzzle . The eight - inch gun could penetrate of armour and the seven - inch gun could penetrate . " Northumberland " was partially rearmed in 1875 with an armament of 7 nine - inch guns , 4 on the main deck , 2 forward chase guns and 1 rear chase gun . Two eight - inch guns replaced the seven - inchers on the main deck at the stern ; the other 18 eight - inch guns remained where they were . In 1886 two breech - loading guns replaced two eight - inch guns . Six quick - firing ( QF ) 4 . 7 - inch ( 120 - mm ) guns , 10 QF 3 - pounder Hotchkiss guns , and six machine gun s were later added . Armour . Unlike her half - sisters , the entire side of " Northumberland " s hull was not covered with wrought iron armour . To compensate for the additional weight of her armament , only her battery was protected above the main deck . The ship was fitted with a complete waterline armour belt that tapered from at the ends to amidships . The armour extended below the waterline . The sides of the battery were long and it was protected by 5 . 5 - inch armour on all sides , including transverse bulkheads fore and aft of the guns . The two forward chase guns on the upper deck were also protected by armoured bulkheads , but the stern chase guns on that same deck were entirely unprotected . The armour was backed by of teak . The ship also had a conning tower protected by 4 . 5 - inch armour plates . Construction and service . " Northumberland " , named after the ceremonial county , was ordered on 2 September 1861 from the Millwall Ironworks . She was laid down on 10 October 1861 at its shipyard in Millwall , London . She was altered while on the building slip after Sir Edward Reed succeeded Isaac Watts as Chief Constructor . Unlike her half - sisters , the ship spent five years on the stocks before she was ready to be launched , partially due to frequent changes in design , although " Northumberland " was much closer to completion . The additional weight caused her stick for an hour on the slipway before she slid halfway down with her stern only supported by air , threatening to buckle the ship . Efforts by hydraulic jack s and tugboats failed to get her into the water on the next spring tide failed , but the use of pontoons on 17 April 1866 proved successful . Her builders went into bankruptcy while the ship was being launched and the liquidators seized " Northumberland " as a company asset once she was in the water . Eight months passed before the Admiralty could take possession and begin fitting out the ship . She was commissioned in October 1868 and completed on 8 October for a cost a total of £444 , 256 . The ship ' s first posting was to the Channel Fleet , where she remained until 1873 . Her first captain , Roderick Dew , had all of her yards painted black so that she could be visually distinguished from her half - sisters , whose yards were white . During this time she helped her half - sister tow a floating drydock from England to Madeira where it would be picked up by and and taken to Bermuda . The ships departed the Nore on 23 June 1869 , loaded down with of coal stowed in bags on their gun decks , and transferred the floating dock 11 days later after an uneventful voyage . She was anchored at Funchal , Madeira , on Christmas Day 1872 , when a storm parted her anchor chain and the ship drifted onto the ram bow of the ironclad . " Northumberland " was seriously damaged below the waterline , with one compartment flooded , though she was able to steam to Malta for repairs . While her half - sister , normally flagship of the Channel Fleet , was refitting in 1873 – 75 , " Agincourt " , normally the flagship of the fleet second - in - command , replaced her as flagship and " Northumberland " became flagship of the second - in - command until " Minotaur " s return to duty . She served as the flagship for Rear Admiral s George Hancock and Lord John Hay . " Northumberland " received her own refit and rearmament from 1875 – 79 and rejoined the Channel Fleet upon its completion . The ship was paid off in 1885 for another refit and became the flagship of Vice Admiral s Sir William Hewett and John Baird , successive commanders of the Channel Fleet , upon her completion in 1887 . " Northumberland " was assigned to the 1st Reserve Squadron at the Isle of Portland in 1890 – 91 and then at Devonport from 1891 – 98 . She was hulked in 1898 as a stoker s ' training ship at the Nore and renamed " Acheron " . From 1909 – 27 the ship served as a coal hulk at Invergordon , renamed " C . 8 " in 1909 and then " C . 68 " in 1926 . The ship was sold in 1927 , but was then resold and renamed as " Stedmound " for service at Dakar until she was scrapped in 1935 . Relics . Two large 1870s half - scale models of the ship are at the Museum of London Docklands .