Early developments The principle employed in using a screw propeller is derived from
stern sculling. In sculling, a single blade is moved through an arc, from side to side taking care to keep presenting the blade to the water at the effective angle. The innovation introduced with the screw propeller was the extension of that arc through more than 360° by attaching the blade to a rotating shaft. Propellers can have a
single blade, but in practice there is nearly always more than one so as to balance the forces involved. The origin of the screw propeller starts with the first records of a water screw, or screw pump, dates back to
Ancient Mesopotamia, a
cuneiform inscription of
Assyrian King
Sennacherib (704–681 BC) describes casting water screws in bronze. This is consistent with classical author
Strabo, who describes the
Hanging Gardens as watered by screws. Later,
Archimedes (c. 287 – c. 212 BC) used a screw to lift water for
irrigation and bailing boats, so famously that it became known as
Archimedes' screw. It was probably an application of spiral movement in space (spirals were a special study of Archimedes) to a hollow segmented water-wheel used for irrigation by
Egyptians for centuries. Later, modern propeller designs usually began with truncating a long screw at the tip. Additionally, a flying toy, the
bamboo-copter, was enjoyed in China beginning around 320 AD. In 1661, Toogood and Hays proposed using screws for waterjet propulsion, though not as a propeller.
Robert Hooke in 1681 designed a horizontal watermill which was remarkably similar to the Kirsten-Boeing vertical axis propeller designed almost two and a half centuries later in 1928; two years later Hooke modified the design to provide motive power for ships through water. In 1693 a Frenchman by the name of Du Quet invented a screw propeller which was tried in 1693 but later abandoned. In 1752, the
Academie des Sciences in Paris granted Burnelli a prize for a design of a propeller-wheel. At about the same time, the French mathematician Alexis-Jean-Pierre Paucton suggested a water propulsion system based on the Archimedean screw. In 1771, the steam-engine inventor
James Watt in a private letter suggested using "spiral oars" to propel boats, although he did not use them with his steam engines or ever implement the idea. One of the first practical and applied uses of a propeller was on a submarine dubbed which was designed in
New Haven, Connecticut, in 1775 by
David Bushnell, a Yale student and inventor, with the help of
Isaac Doolittle, a clock maker, engraver, and brass foundryman of New Haven. Bushnell's brother Ezra Bushnell and Phineas Pratt, a ship's carpenter and clock maker, constructed the hull in
Saybrook, Connecticut. On the night of September 6, 1776, Sergeant
Ezra Lee piloted
Turtle in an attack on in
New York Harbor.
Turtle also has the distinction of being the first submarine used in battle. Bushnell later described the propeller in an October 1787 letter to
Thomas Jefferson: "An oar formed upon the principle of the screw was fixed in the forepart of the vessel its axis entered the vessel and being turned one way rowed the vessel forward but being turned the other way rowed it backward. It was made to be turned by the hand or foot." The brass propeller, like all the brass and moving parts on
Turtle, was crafted by Doolittle. In 1785, Joseph Bramah of England proposed a propeller solution of a rod going through the underwater aft of a boat attached to a bladed propeller, though he never built it. In February 1800,
Edward Shorter of London proposed using a similar propeller attached to a rod angled down temporarily deployed from the deck above the waterline and thus requiring no water seal, and intended only to assist becalmed sailing vessels. He tested it on the transport ship at Gibraltar and Malta, achieving a speed of . In 1802, the American lawyer and inventor
John Stevens built a boat with a rotary steam engine coupled to a four-bladed propeller. The craft achieved a speed of , but Stevens abandoned propellers because of the inherent danger in using the high-pressure steam engines. His subsequent vessels were paddle-wheeled boats.
John Patch, a mariner in
Yarmouth, Nova Scotia, developed a two-bladed, fan-shaped propeller in 1832 and publicly demonstrated it in 1833, propelling a row boat across Yarmouth Harbour and a small coastal schooner at
Saint John, New Brunswick, but his patent application in the United States was rejected until 1849 because he was not an American citizen. His efficient design drew praise in American scientific circles but by then he faced multiple competitors.
Screw propellers Despite experimentation with screw propulsion before the 1830s, few of these inventions were pursued to the testing stage, and those that were proved unsatisfactory for one reason or another. In 1835, two inventors in Britain,
John Ericsson and
Francis Pettit Smith, began working separately on the problem. Smith was first to take out a screw propeller patent on 31 May, while Ericsson, a
Swedish engineer then working in Britain, filed his patent six weeks later. Smith quickly built a small model boat to test his invention, which was demonstrated first on a pond at his
Hendon farm, and later at the Royal Adelaide Gallery of Practical Science in
London, where it was seen by the Secretary of the Navy, Sir William Barrow. Having secured the patronage of a London banker named Wright, Smith then built a , canal boat of six
tons burthen called
Francis Smith, which was fitted with his wooden propeller and demonstrated on the
Paddington Canal from November 1836 to September 1837. In February 1837, the wooden propeller of two turns was damaged during a voyage, and to Smith's surprise, the broken propeller which now consisted of only a single turn doubled the boat's previous speed from about four miles an hour to eight. 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 propeller in flight 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 of attack constant. Their blades were only 5% less efficient than those used 100 years later. Understanding of low-speed propeller
aerodynamics was complete by the 1920s, although increased power and smaller diameters added design constraints.
Alberto Santos Dumont, another early pioneer, applied the knowledge he gained from experiences with airships to make a propeller with a steel shaft and aluminium blades for his
14 bis biplane. Some of his designs used a bent aluminium sheet for blades, thus creating an airfoil shape. They were heavily
undercambered, and this plus the absence of lengthwise twist made them less efficient than the Wright propellers. Even so, this may have been the first use of aluminium in the construction of an airscrew. ==Theory==