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 guns, 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 corvettes 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