demonstrated his boat on the River Thames to senior members of the British Admiralty, including Surveyor of the Navy Sir William Symonds. In spite of the boat achieving a speed of 10 miles an hour, comparable with that of existing paddle steamers, Symonds and his entourage were unimpressed. The Admiralty maintained the view that screw propulsion would be ineffective in ocean-going service, while Symonds himself believed that screw propelled ships could not be steered efficiently. Following this rejection, Ericsson built a second, larger screw-propelled boat, Robert F. Stockton, and had her sailed in 1839 to the United States, where he was soon to gain fame as the designer of the U.S. Navy's first screw-propelled warship, . Apparently aware of the Royal Navy's view that screw propellers would prove unsuitable for seagoing service, Smith determined to prove this assumption wrong. In September 1837, he took his small vessel (now fitted with an iron propeller of a single turn) to sea, steaming from Blackwall, London to Hythe, Kent, with stops at Ramsgate, Dover and Folkestone. On the way back to London on the 25th, Smith's craft was observed making headway in stormy seas by officers of the Royal Navy. This revived Admiralty's interest and Smith was encouraged to build a full size ship to more conclusively demonstrate the technology. was built in 1838 by Henry Wimshurst of London, as the world's first steamship to be driven by a screw propeller. The Archimedes had considerable influence on ship development, encouraging the adoption of screw propulsion by the Royal Navy, in addition to her influence on commercial vessels. Trials with Smith's Archimedes led to a tug-of-war competition in 1845 between and with the screw-driven Rattler pulling the paddle steamer Alecto backward at . The Archimedes also influenced the design of Isambard Kingdom Brunel's in 1843, then the world's largest ship and the first screw-propelled steamship to cross the Atlantic Ocean in August 1845. and were both heavily modified to become the first Royal Navy ships to have steam-powered engines and screw propellers. Both participated in Franklin's lost expedition, last seen in July 1845 near Baffin Bay. Screw propeller design stabilized in the 1880s. Aircraft The Wright brothers pioneered the twisted aerofoil shape of modern aircraft propellers. They realized an air propeller was similar to a wing. They verified this using wind tunnel experiments. They introduced a twist in their blades to keep the angle