SS Great Britain was an advanced passenger steamship

Ocean liner

An ocean liner is a ship designed to transport people from one seaport to another along regular long-distance maritime routes according to a schedule. Liners may also carry cargo or mail, and may sometimes be used for other purposes .Cargo vessels running to a schedule are sometimes referred to as...

 designed by Isambard Kingdom Brunel

Isambard Kingdom Brunel

Isambard Kingdom Brunel, FRS , was a British civil engineer who built bridges and dockyards including the construction of the first major British railway, the Great Western Railway; a series of steamships, including the first propeller-driven transatlantic steamship; and numerous important bridges...

 for the Great Western Steamship Company

Great Western Steamship Company

The Great Western Steam Ship Company operated the first regular transatlantic steamer service from 1838 until 1846. Related to the Great Western Railway, the company's directors expected their new enterprise to achieve the position that was ultimately secured by the Cunard Line...

's transatlantic service between Bristol

Bristol

Bristol is a city, unitary authority area and ceremonial county in South West England, with an estimated population of 433,100 for the unitary authority in 2009, and a surrounding Larger Urban Zone with an estimated 1,070,000 residents in 2007...

 and New York

New York

New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

. While other ships had previously been built of iron or equipped with a screw propeller, Great Britain was the first to combine these features in a large ocean-going ship. She was the first iron steamer to cross the Atlantic, which she did in 1845, in the then-record time of 14 days (one day faster than the previous record holder, the SS Great Western

SS Great Western

SS Great Western of 1838, was an oak-hulled paddle-wheel steamship; the first purpose-built for crossing the Atlantic and the initial unit of the Great Western Steamship Company. Designed by Isambard Kingdom Brunel, Great Western proved satisfactory in service and was the model for all successful...

).

When launched in 1843, Great Britain was by far the largest vessel afloat.