When completed in 1845, "Great Britain" was a revolutionary vessel—the first ship to combine an iron hull with screw propulsion, and at in length and with a 3,400-ton displacement, more than longer and 1,000 tons larger than any ship previously built. Her beam was and her height from keel to main deck, . She had four decks, including the spar (upper) deck, a crew of 120, and was fitted to accommodate a total of 360 passengers, along with 1,200 tons of cargo and 1,200 tons of coal for fuel.