When completed in October 1861, Warrior was by far the largest, fastest, most heavily-armed and most heavily-armoured warship the world had ever seen. She was almost twice the size of La Gloire and thoroughly outclassed the French ship in speed, armour, and gunnery.
Warrior did not introduce any radical new technology, but for the first time combined steam engines, rifled breech-loading guns, iron construction, iron armour, and propeller drive all in one ship, and built to unprecedented scale.
Her construction started intense competition between guns and armour that lasted until air power made battleships obsolete in the Second World War. This race caused her to quickly become obsolete, and she was withdrawn as a fighting unit in May 1883; she is now a museum ship in Portsmouth, United Kingdom.
After strong representations by Admiral Sir Baldwin Wake-Walker, the Surveyor of the Navy, and Henry Corry, the Parliamentary under-secretary to the Admiralty, the Board of Admiralty was moved on 22 November 1858 to call for designs for a wooden-hulled, armour-plated warship, whose dimensions were approximately equal to those of La Gloire.
It does not appear that Wake-Walker or his chief constructor – Isaac Watts – ever seriously considered wood as a building material. Wooden ships had reached their maximum size, and some of the largest were beginning to show signs of fatigue. When coupled with the tremendous problems of timber-supply, and the need for the ship to be built quickly – iron ships were far quicker to build than wooden – the only choice was for an iron-hulled ship. Given that armour plating precluded a design with several gun-decks, a broadside of 17 guns with 15-feet between guns on a single deck gave a central battery of great length. With an appropriate bow, and the creation of a stern, the design called for a ship some long, or longer than any warship built prior to this point.
Warrior was called "the first modern battleship" by W. Brownlee, and her innovative features were described by the same author in an article in "Scientific American.
The Admiralty design was approved at the end of December 1858 but, having no experience with iron hulls, the Board of Admiralty called for designs from the country's most prominent iron shipbuilders. These designs were received in April 1859, but Isaac Watts felt that none of them met the various criteria as well as his own had, and so the tender to build the new iron-cased frigate to the Admiralty design was awarded to the Thames Ironworks and Shipbuilding Company in London. The contract called for a launch date 11 months after the date of the contract - an enormously optimistic timescale that was not met.
Warrior froze to the slipway when she was launched on 29 December 1860, during the coldest winter for 50 years, and six tugs were required to haul her into the river. She was completed on 24 October 1861 at a cost of £357,291, equivalent to £23M in 2006; she entered service just 35 months from when the need for the ship was established in November 1858.
She was then used as a storage hulk, and from 1902 to 1904, as a depot ship for a flotilla of destroyers. Her name was changed to Vernon III in 1904, when she joined Portsmouth-based Vernon, the Royal Navy's torpedo training school. Her role was supplying steam and electricity to the neighbouring hulks that made up Vernon. In October 1923 Vernon was transferred to a newly built shore installation, rendering Warrior and her companion hulks redundant; the Royal Navy put her up for sale in 1924.
Fortunately for Warrior, a downturn in demand for scrap iron had occurred when the Navy decided to sell her off. There was no commercial interest in the old ship, and she remained at Portsmouth for another five years. Finally, in March 1929, efforts aimed towards selling Warrior for scrap were abandoned, and she was taken in tow for her new home: Pembroke Dock in Milford Haven, Wales. Upon arrival she was transformed into a shipkeeper's home and floating oil jetty known only as Oil Fuel Hulk C77. A similar fate had already overtaken several of her successors by this time; in 1926 HMS Valiant became a floating oil tank at Hamoaze, while HMS Agincourt and HMS Northumberland were both stripped down in 1909 and subsequently used as coal hulks.
For the next fifty years, Warrior lay just offshore from an oil depot at Llanion Cove, occasionally being towed to a nearby dry dock for maintenance work. She refueled something close to 5,000 ships between 1929 and 1979. During that time Britain's surviving ironclads and their later equivalents, the battleships, were all sold for scrap. Warrior's last surviving contemporary, Agincourt, was scrapped in 1960 after fifty years' service as a coal hulk at Harwich.
Warrior was saved from being scrapped by the efforts of the Maritime Trust. As the world's first iron-hulled armoured warship, she was recognised as one of the Royal Navy's most historically important warships. In 1968 the Duke of Edinburgh chaired a meeting regarding the possibility of rescuing and restoring Warrior, and a year later the Maritime Trust was established with a view to saving the decrepit ironclad and other historic ships. Throughout the 1970s the Maritime Trust carried out negotiations and feasibility studies regarding Warrior, and finally obtained control of the ship in August 1979.
Restoration of Warrior for use as a museum ship began in August 1979, when she began her journey to her temporary home in the Coal Dock at Hartlepool, where the £8 million restoration project would be carried out, largely funded by the Maritime Trust. Warrior arrived in Hartlepool on 3 September 1979. Restoration work started with the removal of of rubbish, including a thick concrete layer poured onto her upper deck as part of the conversion to an oil jetty. Over the next eight years, Warrior's decks, interior compartments, engines, woodwork and fittings were restored or recreated, her masts, rigging and funnels were recreated, and a new figurehead carved from photographs of the original (destroyed in the 1960s) as a guide. She arrived at her current berth in Portsmouth on 16 June 1987, almost fully restored.