SMITH, Sir Francis Pettit (“Screw” Smith) 1808-1874. Inventor.

Francis Pettit Smith had the most unlikely qualifications to be the inventor of one of the most significant advances in marine engineering - that of the screw propeller. He was born in Aldington, Kent and his father was the postmaster at nearby Hythe. Following education at a private school in Ashford run by the Rev. Alexander Power, Smith began his working life as a grazing farmer on the Romney Marsh, later moving to Hendon in Middlesex where he continued to farm.

As a boy he had acquired great skill in the construction of model boats and took special interest in their means of propulsion. This fascination with boats remained with him and in 1834 on a reservoir near his farm he perfected the propulsion of a model boat by means of a wooden screw driven by a spring. He became utterly convinced that this form of propulsion was greatly superior to the paddle wheel which was in use at the time. The following year he built a superior model with which he performed a number of experiments at Hendon and in 1836 took out a patent for propelling vessels by means of a screw revolving beneath the water at the stern.

Many other attempts had been made to develop this form of propulsion, the first as early as 1681 and by an odd coincidence Dulwich first enters the world of marine engineering in 1824 when John Swan of Coldingham, Berwickshire, who had moved to London and was employed by Messrs. Gordon of Deptford, fitted up a boat with a propeller and tried it on a sheet of water in the grounds of Charles Gordon Esq., of Dulwich Hill. A similar invention was made at virtually the same time as Smith’s by Captain John Ericsson of Sweden who patented it two months later. Smith was, however, completely unaware of the attempts previously made in this field and was convinced of the importance of his own discovery. Fortunately he became dedicated to its development and practically abandoned farming to work on refining his invention. This single-mindedness is perhaps what separates Smith from the numerous others who have been credited with the development of the screw propeller.

His enthusiasm must have been infectious and he soon drew financial support which allowed him to build a 10 ton prototype vessel which he demonstrated on the Paddington Canal and the Thames. During one of these trials the propeller which was designed with a screw of two whole turns struck some obstacle in the water and about half the length of the screw was broken off. It was noticed that the vessel shot forward faster as a consequence of this accident and this discovery led to the fitting of a new screw of a single turn which was found to work much better.

At this time the Royal Navy was using paddle-wheel wooden steam ships. Doubtful of the success of the radical idea of a screw propeller the Admiralty in 1838 requested Smith to allow his vessel to be tried under their inspection. Impressed but not convinced of the Admiralty was anxious to see trials using a larger ship. Various capitalists now came to Smith’s aid and the Ship Propeller Company was formed. In 1839 a specially built ship of 237 tons, named the Archimedes took her maiden voyage. Delivering 80 horse-power and propelled by a single screw, the Archimedes, which was expected to reach a speed of 5 knots was matched against the fastest paddle-driven steamship afloat, the Vulcan. Smith’s four-bladed, propeller driven ship actually delivered double its expected speed in the competition.

It took a reluctant Admiralty five more years of deliberations before it gave the order for 20 warships to be built under Smith’s supervision. Meanwhile, the little Archimedes had been demonstrated in all the major ports in Britain as well as in Amsterdam, Antwerp and Oporto. Isambard Kingdom Brunel was invited to one of these demonstrations and was so impressed with the new invention that he converted the Great Britain, the first iron-hulled ocean going ship, from paddle-driven to screw propeller. It was thus Brunel who signalled to the shipping world the superiority of the screw over the paddle. It still took time for the invention to be widely adopted, so great was investment in the paddle-driven system that the company backing Smith, the Ship Propeller Company lost considerable money because of the lack of orders.

Smith was retained by the Admiralty as an advisor until 1850 but derived little remuneration either from his work for the government or from his commercial operations. Nevertheless, some recognition of his services was made when in 1855 he was granted a pension of £200 per annum by Lord Palmerston. In 1856 his patent, upon which an extension had already been granted, expired and he was obliged to return once more to farming and settled in Guernsey. Ironically, by that year 327 ships and vessels of all classes in the Royal Navy had been fitted with screw propellers. In 1857 he was the recipient of a national testimonial with the gift of plate and a purse of £3000, which was subscribed to by the whole of the shipbuilding and engineering world. It was probably with this sum that he was later able to contemplate building his house at Dulwich.

In 1860 the government appointed him to the post of curator of the Patent Museum at South Kensington. In 1871 a knighthood was conferred upon him and he died at 15 Thurlow Place, South Kensington in February 1874. He had been married twice and had children by each marriage.

Francis Pettit Smith negotiated with the Governors of Dulwich College for the lease of a plot of land on Sydenham Hill where he built his house named Centra House in 1864. The house still stands and at present is being restored from the seven flats into which it was divided, back to a single dwelling. In the grounds Smith had planted a considerable shrubbery and had use of woodlands down to College Road. A later resident added the terra-cotta fountain and renamed the house Dilkoosh. It was again renamed to its present title - Fountain Lodge.

Brian Green