HMS Zealous ( 1864 ) HMS Zealous was one of the three ships ( the others being and ) forming the second group of wooden steam battleships selected in 1860 for conversion to ironclad s . This was done in response to the perceived threat to Britain offered by the large French ironclad building programme . The ship was ordered to the West Coast of Canada after she was completed to represent British interests in the Eastern Pacific Ocean . " Zealous " became the flagship for the Pacific Station for six years until she was relieved in 1872 . She was refitted upon her arrival and subsequently became the guard ship at Southampton until she was paid off in 1875 . The ship was in reserve until she was sold for scrap in 1886 . Design and description . HMS " Zealous " was given a straight stem and a rounded stern , but her hull was otherwise unmodified from her original form ; it had been found that lengthening the hull , as was done in the earlier , led to longitudinal weakness . Her conversion to a central battery ironclad therefore cost less than that of any of her contemporaries , though this was offset with a shorter battery and therefore a less effective broadside . She also carried less armour than the earlier class , and was nearly a knot slower ; however , as she was built to serve in distant waters , and not expected to face opposing ships of significant force , these shortcomings were thought acceptable . " Zealous " was long between perpendiculars and had a beam of . The ship had a draught of forward and aft . She displaced . Propulsion . " Zealous " had a simple horizontal 2 - cylinder horizontal return connecting - rod steam engine driving a single four - bladed , propeller . Steam was provided by eight rectangular boilers at a working pressure of . The engine produced during the ship ' s sea trials in November 1866 which gave the ship a maximum speed of . " Zealous " carried a maximum of of coal . She was ship rigged with three masts and had a sail area of . Her best speed with the propeller disconnected and under sail alone was . Armament . All of the available and guns had already been earmarked for other , more powerful ships . " Zealous " therefore received an armament of guns , which were deemed adequate for her expected service activity , and which , indeed , she retained for the whole of her active career . She was the only battleship ever to have a uniform armament of this calibre , and she , and her half sister , were the only Victorian ironclads to retain their original armament unchanged through their entire active careers . " Zealous " was armed with twenty 7 - inch rifled muzzle - loading guns . Four of these guns were mounted on the upper deck as chase gun s , two each fore and aft . The 16 - calibre 7 - inch gun weighed and fired a shell . It was credited with the nominal ability to penetrate armour . Armour . " Zealous " had a complete waterline belt of wrought iron that was thick amidships and tapered to thick at the bow and stern . From the level of the main deck , it reached below the waterline . The guns on the main deck amidships were protected by a section of 4 . 5 - inch armour , long , with 4 . 5 - inch transverse bulkheads at each end which left the chase guns unprotected . The armour was backed by the sides of the ship which consisted of of teak . The total weight of her armour was . Service history . HMS " Zealous " was laid down on 26 October 1859 as a wooden two - deck , 90 - gun ship of the line by Pembroke Royal Dockyard , but her construction was suspended pending experience with the conversion of her half - sisters of the " Prince Consort " class to broadside ironclads . The Admiralty ordered on 2 July 1862 that she be cut down one deck and converted to an armoured frigate for the price of £239 , 258 . The ship was launched on 7 March 1864 and commissioned in September 1866 , but was not completed until 4 October 1866 . In order to match the French deployment of armored corvette s of the and es in the Pacific Ocean the Admiralty ordered " Zealous " to sail for the west coast of Canada shortly after she was completed . Upon her arrival the ship became the flagship , and reached her operational base at Esquimalt in July 1867 ( Esquimalt was the headquarters of the Pacific Station ) ; she remained moored there , at the end of a telegraph link with Britain , until April 1869 . During this time her only sea service was for gunnery practice on two days every quarter . In January 1870 she picked up a fresh crew at Panama brought out by the two - decker . After six years on station she was relieved by " Revenge " as flagship and started for home . Her bottom had not been cleaned since she had left Great Britain and she could only make a maximum of under sail or steam so her return voyage took five months . " Zealous " struck a rock while sailing through the Straits of Magellan , but was only slightly damaged . She was refitted in Plymouth in April 1873 and then became guard ship at Southampton until 1875 , when she was paid off . The ship was placed in reserve in Portsmouth until sold for scrap in September 1886 . As coal was extremely expensive on the West Coast of the Americas , HMS " Zealous " generally used her sails and covered more miles under sail than any of the other Victorian sailing ironclads , and in her whole career never once travelled in company with another ironclad . She was also the first British ironclad to sail further from Britain than the Mediterranean .