Defence - class ironclad The " Defence " - class ironclads were a class of two warships built for the Royal Navy between 1859 and 1862 . The ships were designed as armoured frigate s in response to an invasion scare sparked by the launch of the and her three sisters in 1858 . They were initially armed with a mix of rifled breech - loading and muzzle - loading smoothbore guns , but the Armstrong breech - loading guns proved unreliable and were withdrawn from service after a few years . Both ships were initially assigned to the Channel Squadron , but was transferred to the Mediterranean Squadron in 1864 . The ships were rearmed in the late 1860s after the completion of their first commission . They alternated between assignments with the fleet and guardship duties with the First Reserve for the rest of their careers . " Resistance " was the first to be paid off in 1880 and was used as a target for gunnery and torpedo trials beginning in 1885 . She was sold for ship breaking in 1898 , but wrecked en route to the breaker ' s yard . was paid off in 1885 and she became a stationary training ship in 1890 until she was sold for scrap in 1935 . Background . In 1859 the Admiralty was not yet convinced that the very expensive ( £377 , 000 ) s , which was over double that of wooden , steam - powered ships of the line , had to be accepted as the norm . They noted that the armour plate of the " Warrior " s was adequate to deflect all ordnance currently afloat , and high speed was not necessary to prevent existing wooden ships from massing their fire against the ironclads . Their Lordships therefore requested a design which , while carrying the same armour , was smaller and slower , and thus cheaper , than the " Warrior " s . Rear Admiral Sir Baldwin Wake Walker , Controller of the Navy , proposed that six ships be built to this design , but he was over - ruled and only two were ordered on 14 December 1859 . The Admiralty ' s decision saddled the Royal Navy with a pair of ships that could not operate with the " Warrior " s in a tactical squadron and were inferior to the French ironclads then under construction . The naval architect Sir Nathaniel Barnaby , a future Constructor of the Navy , considered that a " Defence " - class ship was worth one quarter of a " Warrior " in terms of combat , although they cost about two - thirds as much . Description . The " Defence " class was long between perpendiculars and long overall . They had a beam of and a draught of . The ships displaced and had a tonnage of 3 , 710 tons burthen . Unlike their predecessors , they were fitted with a ram in the shape of a plough . The ends of the hull were subdivided by watertight transverse bulkheads and had a partial double bottom . Each ship had a complement of 460 ( officers and enlisted men ) . The " Defence " class was shorter overall and displaced more than less than the " Warrior " - class ironclads . Propulsion . The " Defence " - class ships had a single two - cylinder trunk steam engine made by John Penn and Sons driving a single propeller . Four rectangular boilers provided steam to the engine at a working pressure of . The engines produced during sea trials which gave the ships maximum speeds of . They carried of coal , enough to steam at . The ironclads were barque - rigged and had a sail area of . The lower masts and bowsprit were made of iron to withstand the shock of ramming . Both ships could make about under sail alone . To reduce wind resistance while under sail alone , the funnel was semi - retractable . Similarly , the propeller could be hoisted up into the stern of the ship to reduce drag while under sail . Armament . The armament of the " Defence " - class ships was intended to be 18 smoothbore , muzzle - loading 68 - pounder gun s , eight on each side on the main deck and one each fore and aft as chase gun s on the upper deck , plus four Armstrong 40 - pounder guns , an early rifled breech loader ( RBL ) design , as . The 68 - pounder weighed and had a range of with solid shot . During construction the armament was changed to include six ( " Defence " ) or eight ( " Resistance " ) rifled 110 - pounder guns , ten 68 - pounders and either two 32 - pounder smoothbores ( " Resistance " ) or four breech - loading guns ( " Defence " ) . The innovative 110 - pounder , whose shell could reach was in short supply when the ironclads were launched , but poor results in armour - penetration tests halted plans to fully equip the ironclads with this gun . The 110 - pounders blew up when other ships used them in action , were labour - intensive to load and fire , and were henceforth only used with a reduced propellant charge , which left them useless in practice . Both ships were rearmed in the late 1860s with 14 seven - inch and 2 eight - inch rifled muzzle - loading guns . The new guns were heavier so fewer could be carried . On both ships the eight - inch guns were mounted amidships on the main deck on the broadside and a pair of seven - inch guns were mounted on the upper deck as fore and aft chase guns . Eight of the remaining seven - inch guns were also placed on the main deck on the broadside where they were protected by the ship ' s armour , but one pair was on the main deck further aft where they were not protected by armour . The two ships differed where the last pair of seven - inch guns was positioned : " Defence " mounted them on the main deck , forward of the armour , while " Resistance " mounted hers on the upper deck . The shell of the weighed while the gun itself weighed . It had a muzzle velocity of and was credited with the ability to penetrate of wrought iron armour at the muzzle . The seven - inch gun fired a shell and could penetrate armour . All of the guns could fire both solid shot and explosive shells . Armour . The " Defence " - class ships had a wrought iron armour belt , thick , that covered amidships . The armour extended from upper deck level to below the waterline . Transverse bulkheads 4 . 5 inches thick protected the guns on the main deck from raking fire . The armour was backed by of teak . The ends of the ship were left entirely unprotected which meant that the steering gear was very vulnerable . They were , however , sub - divided into many watertight compartments to minimize any flooding . Service . HMS " Defence " was assigned to the Channel Squadron upon completion in 1862 . The ship was paid off in 1866 to refit and be re - armed and was briefly reassigned to the Channel Squadron again when she recommissioned in 1868 . " Defence " had brief tours on the North American and Mediterranean Station s , from 1869 to 1872 before she was refitted again from 1872 to 1874 . She became guard ship on the Shannon when she recommissioned . The ship was transferred to the Channel Squadron again in 1876 and then became guard ship in 1879 on the Mersey until 1885 . " Defence " was placed in reserve until 1890 when she was assigned to the mechanical training school at Devonport in 1890 . She was renamed " Indus " when the school adopted that name and served there until sold in 1935 . HMS " Resistance " was the first capital ship in the Royal Navy to be fitted with a ram and was given the nickname of " Old Rammo " . She was initially assigned to the Channel Squadron , but was transferred to the Mediterranean Squadron in 1864 , the first ironclad to be assigned to that squadron . " Resistance " was rearmed in 1867 and became a guardship when recommissioned in 1869 . The ship was reassigned to the Channel Fleet in 1873 before reverting to her former duties in 1877 . " Resistance " was decommissioned in 1880 and was used for gunnery and torpedo trials beginning in 1885 . The ship was sold for scrap in 1898 and foundered the following year en route to the breaker ' s yard . Her wreck was salvaged and later scrapped .