Steamships, Part 2: The Further Adventures of Isambard Kingdom Brunel

Iron Empire

As far back as 1832, Macgregor Laird had taken the iron ship Alburkah to Africa and up the Niger, making it among the first ship of such construction to take the open sea. But the use of iron hulls in British inland navigation can be traced decades earlier, beginning with river barges in the 1780s. An iron plate had far more tensile strength than even an oaken board of the same thickness. This made an iron-hulled ship stronger, lighter, and more spacious inside than an equivalent wooden vessel: a two-inch thickness of iron might replace two-foot’s thickness of timber.[1]  The downsides included susceptibility to corrosion and barnacles, interference with compasses, and, at least at first, the expense of the material.

As we have already seen, the larger the ship, the smaller the proportion of its cargo space that it would need for fuel; but the Great Western and British Queen pushed the limits of the practical size of a wooden ship (in fact, Brunel had bound Great Western’s hull with iron straps to bolster its longitudinal strength and prevent it from breaking in heavy seas).[2] The price of wood in Britain grew ever more dear as her ancient forests disappeared, but to build more massive ships economically also required iron prices to fall: and they did just that, starting in the 1830s, because of a surprisingly simple change in technique.

Ironmongers had noticed long ago that their furnaces produce more metal from the same amount of fuel in the winter months. They assumed that the cooler air produced this result, and so by the nineteenth century it had become a basic tenet of the iron-making business that one should blast cool air into the furnace with the bellows to maximize its efficiency.[3]

This common wisdom was mistaken; entirely backwards, in fact. In 1825, a Glasgow colliery engineer named James Neilson found that a hotter blast made the furnaces more efficient (it was the dryness, not the coolness, of the winter air that had made the difference). Neilson was asked to consult at an ironworks in the village of Muirkirk which was having difficulty with its furnace. He realized that heating the blast air would expand it, and thus increase the pressure of the air flowing into the furnace, strengthening the blast. In 1828 he patented the method of using a stove to heat the blast air. He convinced the Clyde Ironworks to adopt it, and together they perfected the method over the following few years.

The results were astounding. A 600° F blast reduced coal consumption of the furnace by two-thirds and increased output from about five-and-a-half tons of pig iron per day to over eight.[4] On top of all that, this simple innovation allowed the use of plain coal as fuel in lieu of (more expensive) refined coke. Ironmakers had adopted coke in the 1750s because when iron was smelted with raw coal the impurities (especially sulfur) in the fuel made the resulting metal too brittle. But the hot blast sent the temperature inside the furnace so high that it drove the sulfur out in the slag waste rather than baking it into the iron. During the 1830s and 40s, Neilson’s hot blast technique spread from Scotland across all of Great Britain, and drove a rapid increase in iron production, from 0.7 million tons in 1830 to over two million in 1850. This cut the market price per ton of pig iron in half.[5]

With its vast reserves of coal and iron, made accessible with the power of steam pumps (themselves made in Britain of British iron and fueled by British coal), Britain was perfectly placed to supply the demand induced by this decline in price. Much of the growth in iron output went to exports, strengthening the commercial sinews of the British empire while providing the raw material of industrialization to the rest of the world. The frenzies of railroad building in the United States and continental Europe in the middle of the nineteenth century relied heavily on British rails made from British iron: in 1849, for example, the Baltimore and Ohio railroad secured 22,000 tons of rails from a Welsh trading concern.[6] The hunger of the rapidly growing United States for iron proved insatiable; circa 1850 the young nation imported about 450,000 tons of British iron per year.[7]

Good Engineering Makes Bad Business

The virtues of iron were also soon on the brain of Isambard Kingdom Brunel. The Great Western Steam Ship Company’s plan for a successor to Great Western began sensibly enough; they would build a slightly improved sister ship of similar design. But Brunel and his partners were seduced, in the fall of 1838, by the appearance in Bristol harbor of an all-iron channel steamer called Rainbow, the largest such ship yet built. Brunel’s associates Claxton and Patterson took a reconnaissance voyage on her to Antwerp and upon their return all three men became convinced that they should build in iron.[8]

As if that were not enough novelty to take on in one design, in May 1840 another innovative ship steamed into Bristol harbor, leaving Brunel and his associates swooning one more. The aptly named Archimedes, designed by Francis Petit Smith, swam through the water with unprecedented smoothness and efficiency, powered by a screw propeller rather than paddle wheels.[9] Any well-educated nineteenth-century engineer knew that paddles wasted a huge amount of energy pushing water down at the front of the wheel and lifting it up at the back. Nor was screw propulsion a surprising new idea in 1840. As we have seen, early steamboat inventors tried out just about every imaginable means of pushing or pulling a ship. In his very thorough Treatise on the Screw Propeller, the engineer John Bourne cites fifty some-odd proposals, patents, or practical attempts at screw propulsion prior toSmith’s.[10]

After so many failures, most practical engineers assumed (reasonably enough) that the screw could never replace the proven (albeit wasteful) paddlewheel. The difficulties were numerous, including reducing vibration, transmitting power effectively to the screw, and choosing its shape, size, and angle among many potential alternatives. Most fundamental though, was producing sufficient thrust: early steam engines operated at modest speed, cycling every three seconds or so. At twenty revolutions per minute, a screw would have to be of an impractical diameter to actually push a ship forward rapidly.

Smith overcame this last problem with a gearing system to allow the propeller shaft to turn 140 times per minute. His propeller design at first consisted of a true helical screw, of two turns (which created excessive friction), then later a single turn. Then, in 1840 he refitted Archimedes with a more recognizably modern propeller with two blades (each of half a turn).[11]

Even with these design improvements, Brunel found that noise and vibration made the Archimedes of 1840 “uninhabitable” for passengers.[12]  But he had unshakeable faith in its potential. No doubt, advocates of the screw could tout many potential advantages over the paddlewheel: a lower center of gravity, a more spacious interior, more maneuverability in narrow channels, and more efficient use of fuel  (especially in headwinds, which caught the paddles full on, and rolling sidelong waves, which would lift one paddlewheel or the other out of the water).[13] 

So, the weary investors of the Great Western Steam Ship Company saw the timetable of the  Great Britain’s construction set back once more, in order to incorporate a screw. As steamship historian Stephen Fox put it, “[i]n commercial terms, what the Great Western company needed in that fall of 1840 was a second ship, as soon as possible, to compete with the newly established Cunard line,” but that is not what they would get.[14] The completed ship finally launched in 1843, but did not take to sea for a transatlantic voyage until July 1845, having already cost the company some £200,000 pounds in total. With 322 feet of black iron hull driven by a 1000 horsepower Maudslay engine and a massive 36-ton propeller shaft, she dwarfed Great Western. Her all-iron construction gave an impression of gossamer lightness that fascinated a public used to burly wood.[15]

The Launching of the Great Britain.

But if her appearance impressed, her performance at sea did not. Her propeller fell apart, her engine failed to achieve the expected speed and she rolled badly in a swell. After major, expensive renovations in the winter of 1845, she ran aground at the end of the 1846 sailing season at Dundrum Bay off Ireland. Her iron hull proved sturdier than the organization that had constructed it: by the time she was at last floated free in August 1847, the Great Western Steam Company had already sunk. Another concern bought Great Britain for £25,000, and she ended up plying the route to Australia, operating mostly by sail.[16]

In the long run, Brunel and his partners were right that iron hulls and screw propulsion would surpass wood and paddles, but Great Britain failed to prove it. The upstart Inman steamer line launched the iron-hulled, screw-powered City of Glasgow in 1850, which did prove that the ideas behind Great Britain could be turned to commercial success. But the more conservative Cunard line did not dispatch its first iron-hulled ship on its maiden voyage until 1856. Though even larger than Great Britain, at 376 feet and 3600 tons, the Persia still sported paddlewheels. This did not prevent her from booking more passengers than any other steamship to date, nor from setting a transatlantic speed record.[17] Not until the end of the 1860s did oceanic paddle steamers become obsolete.

The Archimedes. Without any visible wheels, she looked deceptively like a typical sailing schooner, but for the telltale smokestack.

A Glorious Folly

For a time, Brunel walked away from shipbuilding. Then, late in 1851, he began crafting plans for a new liner to far surpass even Great Britain, one large enough to ply the routes to Indian and Australia without coaling stops on the African coast. Stopping to refuel wasted time but also quite a lot of money: coal in Africa cost far more than in Europe, because another ship had to bring it there in the first place.[18]   

Because it would sail around Africa, not towards America, the new ship was christened Great Eastern. Monstrous in all its dimensions, the Great Eastern, can only be regarded as a monster in truth, in the archaic sense of “a prodigy birthed outside the natural order of things”; it was without precedent and without issue.[19] Given the total failure of Brunel’s last steam liner company, not to mention other examples of excessive exuberance in his past, such as an atmospheric railway project that shut down within a year, it is hard to conceive of how he was able to convince new backers to finance this wild new idea. He did have the help of one new ally, an ambitious Scottish shipbuilder named John Russell, who was also wracked by career disappointment and eager for a comeback.

Together they built an astonishing vessel: at 690 feet long and over 22,000 tons, it exceeded in size every other ship built to its time, and also every other ship built in the balance of the nineteenth century. It would carry (in theory) 4,000 passengers and 18,000 tons of coal or cargo, and mount both paddlewheels and a propeller, the latter powered by the largest steam engine ever built, of 1600 horsepower. Brunel died of a stroke in 1859, and never saw the ship take to sea. That is just as well, for it failed even more brutally than the Great Britain. It was slow, rolled badly, maneuvered poorly, and demanded prodigious quantities of labor and fuel.[20] Like Great Britain, after a brief service its owners auctioned it off to new buyers at a crushing loss. Great Eastern did, however, have still in its future a key role to play in the extension of British imperial and commercial power, as we shall see.

The Great Eastern in harbor in Wales in 1860. Note the ‘normal-size’ three-masted ship in the foreground for scale.

I have lingered on Brunel’s career for so long not because he was of unparalleled import to the history of the age of steam (he was not), but because his character and his ambition fascinate me. He innovated boldly, but rarely as effectively as his more circumspect peers, such as Samuel Cunard. Much—though certainly not all—of his career consists of glorious failure. Whether you, dear reader, emphasize the glory or the failure, may depend on the width of the romantic streak that runs through your soul.

[1] Christopher Claxton, History and Description of the Steam-Ship Great Britain (New York: J. Smith Homans, 1845), 22.

[2] The story of Zheng He’s 450-foot-long treasure ships is now familiar to many, but a wooden hull built on such dimensions using known medieval ship-building techniques would crack apart at sea. The source for this exceptional size is a Ming history written over two centuries after the fact, and it is therefore almost certainly inflated (whether intentionally or accidentally). Sally K. Church, “Zheng He: An Investigation into the Plausibility of 450-ft Treasure Ships,” Monumenta Serica 53 (2005), 37-38.

[3] Charles K. Hyde, Technological Change and The British Iron Industry, 1700-1870 (Princeton: Princeton University Press, 1977), 146.

[4] Hyde, 151; Alan Birch, The Economic History of the British Iron and Steel Industry, 1784-1879, (New York: Augustus M. Kelly, 1968), 181-183.

[5] Hyde, 151-52, 156-57, 163-64.

[6] Birch, 219-221.

[7] Birch, 227. These figures separate values in the source for pig iron and bar iron (which is wrought iron produced from pig iron, and would include rails).

[8] Fox, Transatlantic, 144, 147.

[9] Rolt, Isambard Kingdom Brunel, 264.

[10] John Bourne, A Treatise on the Screw Propeller (London: Longman, Brown, Green and Longmans, 1855), 8-27.

[11] Edgar C. Smith, A Short History of Naval and Marine Engineering (Cambridge: Cambridge University Press, 1938), 64-65, 70; Bourne, A Treatise on the Screw Propeller, 88.

[12] Fox, Transatlantic, 149.

[13] Claxton, History and Description of the Steam-Ship Great Britain, 25-26.

[14] Fox, Transatlantic, 149.

[15] Fox, Transatlantic, 150-53.

[16] Fox, Transatlantic, 153-155; Brunel, The Life of Isambard Kingdom Brunel, 281-82.

[17] Fox, Transatlantic, 162-63.

[18] Fox, Transatlantic, 155, 159-160.

[19] Katharine Park and Lorraine J. Daston. “Unnatural Conceptions: The Study of Monsters in Sixteenth- and Seventeenth-Century France and England,” Past and Present 92 (August 1981), 20-54.

[20] Fox, Taransatlantic, 160-61, 165-66.

5 thoughts on “Steamships, Part 2: The Further Adventures of Isambard Kingdom Brunel”

  1. Excellent article! One question… are there plans in existence of the original engine? I make scale models of historic engines and that one sounds like it would be a great subject. I could find nothing useful on searching the Internet.


    1. I don’t know, unfortunately. I would guess that one would have to dig through archives in the U.K. to find out.


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