Editing SS Great Britain (section)

===Adoption of iron hull===
[[File:Life of Brunel - Fig 13 - Transverse Section of the ‘Great Britain’ Steam-Ship.png|thumb|Hull section of the ''Great Britain'', showing the boiler]]
Two chance encounters were profoundly to affect the design of ''Great Britain''. In late 1838, [[John Laird (shipbuilder)|John Laird's]] {{convert|213|ft|m|adj=on}} [[English Channel]] [[packet ship]] ''Rainbow''—the largest iron-[[hull (watercraft)|hulled]] ship then in service—made a stop at Bristol. Brunel dispatched his associates Christopher Claxton and William Patterson to make a return voyage to [[Antwerp]] on ''Rainbow'' to assess the utility of the new building material. Both men returned as converts to iron-hulled technology, and Brunel scrapped his plans to build a wooden ship and persuaded the company directors to build an iron-hulled ship. ''Great Britain''{{'}}s builders recognised a number of advantages of iron over the traditional wooden hull. Wood was becoming more expensive, while iron was getting cheaper. Iron hulls were not subject to [[dry rot]] or [[woodworm]], and they were also lighter in weight and less bulky. The chief advantage of the iron hull was its much greater structural strength. The practical limit on the length of a wooden-hulled ship is about {{cvt|300|ft}}, after which [[hogging and sagging|hogging]]—the flexing of the hull as waves pass beneath it—becomes too great. Iron hulls are far less subject to hogging so the potential size of an iron-hulled ship is much greater.{{sfn|Fox|2003|p=144}} The ship's designers, led by Brunel, were initially cautious in the adaptation of their plans to iron-hulled technology. With each successive draft however, the ship grew ever larger and bolder in conception. By the fifth draft, the vessel had grown to {{cvt|3400|LT}}, over {{cvt|1000|LT}} larger than any ship then in existence.{{sfn|Fox|2003|pp=147–148}}