All vessels, except for sail-alone boats and water jets, have propellers. Despite being a crucial component of nautical engineering that allows ships to move, they are normally out of sight, and they can be arranged in different configurations. Have you ever thought about when they were invented and how they evolved into the sophisticated examples we use today? Volunteer Roger Burns looks at 19th century innovators that contributed to the development of propellers, focusing in particular on Henrietta Vansittart.
Early mechanical propulsion used side paddles, or stern paddles in America. These lasted through the late 19th century when an innovative way to move vessels was invented: the propeller. In the 19th century propellers were usually made in cast iron, while nowadays they are produced using a variety of stainless steel and other alloys, plastic, and carbon fibre.
Various people claimed to have been the inventors of early propellers. English engineer and inventor Edward Shorter patented the “perpetual sculling machine” requiring the use of a driving capstan in 1800. In 1836 English inventor Francis Pettit Smith patented the revolving screw; this was located on the stern of the vessel, beneath the water. In 1839, the SS Archimedes was credited as being the world’s first steamship to be driven by a screw propeller. A brief search in the British Newspaper Archive shows a variety of propeller makers, all making their claims!
A propeller is usually described by two figures, the diameter and the pitch.
Diameter: Diameter of the circle scribed by the blades.
Pitch: Theoretical distance that the propeller would travel forward through a soft mass in one revolution (imagine a screw through wood!)
Propeller Hub, Boss or Cone: Central element between the blades and the shaft
Shaft: Tube connecting the propeller to the engine
The Lowe Family
James Lowe was born in 1798 and, aged 13, he started working for Edward Shorter to whom he was apprenticed two years later. From 1819 to 1825, James took part in three whaling voyages on the SV Amelia Wilson. Back to London he went into partnership with his former master Edward Shorter and married Mary Barnes on 30 May 1825. James and Mary had ten children, the fourth of which was named Henrietta. She was born in Southwark in 1840.
In 1834 James’ research on propellers were causing him to lose money. This prompted him to leave his partnership with Shorter and to team up with a more supportive business partner. The Admiralty were at this time considering alternative propulsion to paddle wheels, and although a number of inventors were working with propellers, James’s propeller was selected as the one to test on steamship Wizard. Soon after, in 1938, James took out a Patent (GB7599) for his submerged stern propeller. In 1844, he won a court action against Penn & Co for infringement of this patent. Another Patent (GB14263) followed in 1852, by which time he was living in poverty having spent all his wife’s fortune on his experiments with propellers (Figure 1).
Figure 1: Patent model showing screw propeller with James Lowe blade principle 1851-1852,
(Source: James Lowe, CC BY-SA 4.0, via Wikimedia Commons)
In the quest to demonstrate the advantages of the propeller against the use of side-paddler, James’s propeller was trialled by fitting it onto HMS Rattler. A “tug-o-war” with paddler HMS Alecto was then staged in the North Sea on 3 April 1845, in flat calm conditions. The vessels were roped stern to stern and HMS Rattler won against HMS Alecto (Figure 2).
James’ efforts to prove the advantages of propellers were brutally interrupted in 1866 when he was killed by a wagon on Blackfriars Road in London.
Figure 2: HMS Rattler towing HMS Alecto (Source: Royal Museums Greenwich, Public Domain via Wikimedia Commons)
Henrietta Lowe, who had been taking a great interest in her father’s work on propellers, married Lieutenant Frederick Vansittart of the 14th King’s Regiment of Light Dragoons in 1855. In 1857 Henrietta was with James onboard HMS Bullfinch, one of the 98 Albacore Class gunboats built for the Crimean War, when her father’s latest propeller was tested.
On James’s death, Henrietta took over her father’s work, determined that he would not be forgotten. Despite no formal training she improved on James’ propeller, and, on 18 September 1868, she was granted Patent No 2877 for the Lowe-Vansittart propeller. This machine showed “improvements in the construction of screw propellers”, resulting in ships traveling faster, with less vibrations, and using less fuel.
In 1869 when Henrietta was only 29, the Admiralty satisfactorily trialled and fitted her propeller to HMS Druid. Henrietta was very busy, engrossed in the on-site supervision of detailed design, manufacture, and fitting of her propellers to many ships. Her propellers were apparently fitted on over 30 vessels, such as HMS Coquette, HMS Gorgon, HMS Hecate, and HMS Decoy. This device was also used on mercantile ships, including the iron hulled passenger/cargo steamer SS Scandinavian (ON63753) launched on 8 November 1869 in Glasgow. This vessel underwent testing using the original two-cylinder double acting 400hp engine with the Lowe-Vansittart propeller. The Ships Master and the Liverpool Pilot witnessed first-hand how this device used 15% less of the fuel while increasing the speed of the boat of ¼ knots. In addition, there were no vibration, a tighter turning circle, and, compared with other contemporary propellers, the Lowe-Vansittart propeller had no problems steaming in reverse, for example when leaving the dockside. The propeller dimensions were 18 ft. (c. 5.486m) diameter and 25 ft. (c. 7.62m) pitch.
In 1876 Henrietta was the first woman to present a paper the Society of Arts in London. Her paper was titled “The screw propeller of 1838 and its subsequent improvements”. Some years later, in 1882, she published a paper, titled The history of the Lowe Vansittart Propeller and a short extract of the life of the late Mr James Lowe, the successful inventor of screw ships from their first introduction to commemorate her father’s work and achievements (Figure 3).
Henrietta travelled to Tynemouth to attend the September 1882 North East Coast Exhibition of Naval Architecture and Marine Engineering to demonstrate her propeller. Sadly, she was found in a confused state of mind and, on the very day her patent expired as fees had not been remitted, she was admitted, to Tyne City Lunatic Asylum at Coxlodge, Gosforth, where she died on 8 February 1883.
Henrietta died an untimely death, but her contribution to the profession were ground-breaking. Her work gained her great respect and is a testimony to the invaluable achievements of all the women successfully practising as engineers in Victorian Britain.
Several medals and patents were awarded to Henrietta in many countries, including Austria, Belgium, France, Holland, Italy, and the USA. So far, no shipwreck has been found being definitively fitted with a Lowe-Vansittart propeller. Nevertheless, some archaeological examples of this type of propeller include those found on the wrecks of First World War German submarines SM U-8 and U-90.
Figure 3: Henrietta Vansittart’s 1852 publication (Source: Public Domain via Wikimedia Commons)
Henrietta’s 1869 American Patent1 demonstrates her technical grasp and expert knowledge on propellers. One of Henrietta’s arguments was that her design did away with “churning” of water, a term describing “useless stirring water near the centre of motion”. She argues the importance of not treating the water as a solid when building a propeller, as well as the significance of the shape and the speed of the vessel to properly fit the propeller:
Two extracts from the Patent, showing that the shape of the vessel and its speed are important, include:
- Screw-propellers formed of a true screw, or its segments, have heretofore, been constructed on the hypothesis that water is a solid, and that the best way of obtaining propelling-power, or resistance from it, is to cut a direct screw-passage through it, in such a manner as shall offer the least resistance to the motion of the blades, and shall divide the water by the least possible distance.
- Experience has, however, demonstrated that the above theory is incorrect, and has served to prove, conclusively, that water ought not to be thus treated, but should be considered as a subtle fluid, capable of finding its way into hollows and curves in the blades of the propeller, even when these are in rapid motion. It has been found (in respect to the curves of these blades) that the proper angle of the edge, or entering part of the blade, is difficult to determine, and, at the same time, is all-important to the proper action of the propeller. […]
- Careful experiments have shown that the best or proper angle for the leading edges of the blades varies according to the angle or curve of the water-lines of the after-part or run of the vessel, and also varies with and according to the velocity of the vessel through the water. The velocity of the vessel, therefore, as well as the curvature of the water-line, determines an invisible line, which indicates the points and angle at which the water recedes from the vessel while the latter is in motion; or, in other words, as the vessel moves forward the disturbed water will leave the sides of the vessel in a curved line, which will vary according to the lines of the vessel and its velocity.