Brunel proposed to extend his transport network across the Atlantic, and so the Great Western Steamship Company was co-established for this purpose, by Isambard Kingdom Brunel and Thomas Guppy, a marine engineer and businessman. A construction committee was formed of Brunel, Guppy, Captain Claxton RN who was Quay Warden of Bristol Docks, and William Patterson, a shipbuilder and Navel Architect who's own company was responsible for building Brunel's designs, including the Great Britain.
The S S Great Britain was launched in Bristol on 19 July 1843. Construction took place in a dry dock (now known as the Great Western Yard) which the Steamship Company leased and enlarged, as unlike the Great Western, launched before her in 1838, she was too large to be built in Patterson's yard.
She was 289 feet long by 50 feet wide and weighed 3270 tons, easily the biggest ship in the world. She was the first large ship to be built of iron, and the first large ship to be driven by a screw. She had the most powerful engine built up to that time, over 1000 horsepower, and the first balanced rudder. She had a double bottom and watertight compartments.
Built to provide a shuttle service for the growing transatlantic passenger trade between England and the United States, she was the first propeller driven, ocean going, iron wrought ship in the world and was unique at the time in terms of construction as well as size. She was built of Iron on the recommendation of the construction committee. The Great Western, launched before her, was built of wood. The Great Britain was the 'mother' of all modern ships.
She was salvaged and returned from the Falkland Islands to Bristol in 1970, where she has been restored to her former glory and is moored in the Great Western Dry Dock, where she was built.