Smith, Sir Francis Pettit

SUBJECT AREA: Ports and shipping

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b. 9 February 1808 Copperhurst Farm, near Hythe, Kent, England

d. 12 February 1874 South Kensington, London, England

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English inventor of the screw propeller.

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Smith was the only son of Charles Smith, Postmaster at Hythe, and his wife Sarah (née Pettit). After education at a private school in Ashford, Kent, he took to farming, first on Romney Marsh, then at Hendon, Middlesex. As a boy, he showed much skill in the construction of model boats, especially in devising their means of propulsion. He maintained this interest into adult life and in 1835 he made a model propelled by a screw driven by a spring. This worked so well that he became convinced that the screw propeller offered a better method of propulsion than the paddle wheels that were then in general use. This notion so fired his enthusiasm that he virtually gave up farming to devote himself to perfecting his invention. The following year he produced a better model, which he successfully demonstrated to friends on his farm at Hendon and afterwards to the public at the Adelaide Gallery in London. On 31 May 1836 Smith was granted a patent for the propulsion of vessels by means of a screw.

The idea of screw propulsion was not new, however, for it had been mooted as early as the seventeenth century and since then several proposals had been advanced, but without successful practical application. Indeed, simultaneously but quite independently of Smith, the Swedish engineer John Ericsson had invented the ship's propeller and obtained a patent on 13 July 1836, just weeks after Smith. But Smith was completely unaware of this and pursued his own device in the belief that he was the sole inventor.

With some financial and technical backing, Smith was able to construct a 10 ton boat driven by a screw and powered by a steam engine of about 6 hp (4.5 kW). After showing it off to the public, Smith tried it out at sea, from Ramsgate round to Dover and Hythe, returning in stormy weather. The screw performed well in both calm and rough water. The engineering world seemed opposed to the new method of propulsion, but the Admiralty gave cautious encouragement in 1839 by ordering that the 237 ton Archimedes be equipped with a screw. It showed itself superior to the Vulcan, one of the fastest paddle-driven ships in the Navy. The ship was put through its paces in several ports, including Bristol, where Isambard Kingdom Brunel was constructing his Great Britain, the first large iron ocean-going vessel. Brunel was so impressed that he adapted his ship for screw propulsion.

Meanwhile, in spite of favourable reports, the Admiralty were dragging their feet and ordered further trials, fitting Smith's four-bladed propeller to the Rattler, then under construction and completed in 1844. The trials were a complete success and propelled their lordships of the Admiralty to a decision to equip twenty ships with screw propulsion, under Smith's supervision.

At last the superiority of screw propulsion was generally accepted and virtually universally adopted. Yet Smith gained little financial reward for his invention and in 1850 he retired to Guernsey to resume his farming life. In 1860 financial pressures compelled him to accept the position of Curator of Patent Models at the Patent Museum in South Kensington, London, a post he held until his death. Belated recognition by the Government, then headed by Lord Palmerston, came in 1855 with the grant of an annual pension of £200. Two years later Smith received unofficial recognition when he was presented with a national testimonial, consisting of a service of plate and nearly £3,000 in cash subscribed largely by the shipbuilding and engineering community. Finally, in 1871 Smith was honoured with a knighthood.

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Principal Honours and Distinctions

Knighted 1871.

Further Reading

Obituary, 1874, Illustrated London News (7 February).

1856, On the Invention and Progress of the Screw Propeller, London (provides biographical details).

Smith and his invention are referred to in papers in Transactions of the Newcomen Society, 14 (1934): 9; 19 (1939): 145–8, 155–7, 161–4, 237–9.

LRD