Looking Astern: When iron began to float
From Ocean Navigator #124 September/October 2002
John Wilkinson of Britain was the undisputed king of the iron industry in the 18th century. Brilliant and eccentric, Wilkinson envisioned a world made of iron and became wealthy by creating new markets for the metal. These included constructing what was probably the world's first boat with an iron hull: a river barge built just two years before the French Revolution.
Although Wilkinson's barge demonstrated conclusively to the skeptical that an iron-built hull would actually float, shipyards in Britain did not immediately rush to experiment with the novel idea of building ships of iron. In fact, it was not until the 1830s that iron-hulled sailing and steam vessels began to appear in any number.
Nautical Magazine reported in 1834:
"The importance of these vessels is daily increasing in general estimation, arising from the peculiar advantages they possess, of being not only water-tight and very durable, but, from their cleanliness, peculiarly healthy and desirable vessels. They afford no harbour for vermin, like those of wood, and in warm climates, the great conducting power of the metal gives off the heat to the water, so that they nearly assume its temperature. It was technically said of the Alburkha, the first of these vessels that ever went to sea, that she did not make 'a cup of water,' and we know that, in the course of her voyage up the Niger, she was the favorite vessel on this account, as well as from the circumstance of her being the healthier of the two vessels. The Quorra, that accompanied her, very shortly lost two-thirds of her crew, while in the Alburkha, the sickness was nothing in comparison."
But iron hulls proved to be more than just healthy. In Britain, where timber was becoming costly, iron began to look like a viable alternative for vessel construction. The United States and Britain's North American colonies, unimpeded by any shortage of good shipbuilding timber, continued to construct wooden brigs, barks and fast little schooners in vast numbers to compete commercially with Britain in the expanding international sea trade of the period.
In 1836, Lloyd's Register listed its first iron vessel, the ketch-rigged Goliath, followed two years later by the world's first ship-rigged sailing vessel, Ironsides. By the 1840s, British shipbuilders were discovering that riveted iron was considerably stronger than wood for hull construction, especially for very large vessels. Also, iron framing took up considerably less space than wood framing, resulting in more usable cargo space within the hull.So it came as no surprise in 1843 when Isambard Brunel's revolutionary 3,270-ton, 322-foot, six-masted S.S. Great Britain left its dry dock with hull and frames constructed entirely of iron. Great Britain's appearance essentially marked the true beginning of the age of the iron ship, with total world tonnage reaching a peak around 1890, when iron's use began to decline and steel came into common use for hull construction.
Great Britain became the first vessel with an iron hull to cross the Atlantic, and was a major transporter of British emigrants to America and Australia during its working life.
The durability of iron hull construction is amply demonstrated in Bristol, England, where S.S. Great Britain sits snugly, undergoing restoration in the same dry dock where it was completed nearly 160 years ago.