PortandTerminal.com, October 12, 2020
HALIFAX, NOVA SCOTIA – Ship propellers are a relatively new invention. The first was invented somewhere around 250 years ago. The first crossing of the Atlantic in a propellered vessel happened only 175 years ago. For thousands of years, it seems that the maritime world managed without complaint using only oars, sail and rudder to handle its locomotion and steering needs.
Who actually invented the first ship propeller is open to debate — there are a number of claimants to the title. Between 1750 and the 1830s numerous patents for marine propellers were taken out by various inventors, though few of these inventions were pursued to the testing stage, and those that were proved unsatisfactory for one reason or another.
We won’t try to unravel the veracity of the competing claims to “first” in this article — the truth is that there were many inventors working on developing propellers at around the same time. We will however try to give an overview of some of the highlights along the way.
To do that though, first, we need to dive back deep into history to pay homage to Archimedes and Leonardo da Vinci. The invention of the propeller is largely thanks to their creativity and genius.
Archimedes was a Greek mathematician, physicist, engineer, inventor, and astronomer who lived around 300 years BCE. By any account, he was a genius and a polymath.
The king he served, King Hiero II, commissioned Archimedes to design a huge ship, the Syracusia, which could be used for luxury travel, carrying supplies, and as a naval warship.
The Syracusia is said to have been the largest ship built in classical antiquity. It was capable of carrying 600 people and included garden decorations, a gymnasium and a temple dedicated to the goddess Aphrodite (Greek goddess of sexual love and beauty) among its facilities.
Since a ship of this size would leak a considerable amount of water through the hull, the Archimedes’ screw was purportedly developed in order to remove the bilge water.
Archimedes’ screw was a device with a revolving screw-shaped blade inside a cylinder. The screw was turned by hand and would pull water from a low-lying body up to a higher level where the fluid could be dumped overboard in the case of a ship’s bilge water.
The screw was also useful for moving water from a low lying water source and into irrigation canals in farming. Archimedes’ insight that a turning device can move water was absolutely foundational to the later invention of the propeller.
Leonardo da Vinci’s propeller-driven marvels
In the year 1493 Leonardo da Vinci drew a stunning picture of what the concept of flight would look like using something similar to a propeller.
Some speculate that Leonardo’s invention for the helicopter (see drawing above) may have been conceptualized while he was watching the seeds of a maple tree spin as they fell.
While watching the seeds fall Leonardo may have asked himself – “If the seed spins while it is falling, would it rise through the air if it was spun in the opposite direction?”
Once da Vinci’s vision was put to paper it looks unmistakenly similar to what a modern helicopter today looks like. Like Archimedes, who’s insight was that a propeller-like shape could move water, da Vinci saw that it could move air too and in doing so, provide lift.
David Bushnell’s “Turtle” (1776)
David Bushnell was the Yale-educated son of a Connecticut farmer. While studying at Yale, Bushnell had experimented with methods to make gunpowder explode underwater — an innovation that would be much in demand once the American Revolution started.
In April of 1775, Bushnell’s last year at Yale, news of the battles at Lexington and Concord electrified Connecticut. The college closed early and Bushnell went home where he continued to work, now in earnest, on building a submarine that would deliver his underwater mine or explosives to help in the war effort.
Bushnell developed a small submarine that could be propelled forward and backwards using a propeller operated by a treadle and a hand crank. A vertical propeller on the top of the boat assisted with the ascent. The Turtle used phosphorescent moss as the interior light source because a candle would use up too much of the available oxygen.
The two propellers that Bushnell invented and described as “oars” and “like the blades of a windmill” were his greatest contribution to future marine development.
Josef Ressel (1793-1857)
Joseph Ressel is credited by some (including Wikipedia) as being the inventor of the ship propeller. In a park in Vienna, Austria there is even a monument of Ressel that proudly commemorates him as “the one and only inventor of the screw propeller and steam shipping”.
Ressel was of Czech-German descent but worked as an Austrian forester who’s job was to supply Austria’s navy with wood.
In 1812, he developed a design for a ship whose propulsion was based on the use of Archimedes’ screw. He successfully tested a screw propeller on a boat in 1826 and obtained the Austrian patent for this propeller in 1827. In 1829 he built the screw-steamer Civetta, which had a displacement of 33 tons. Ressel’s new propeller permitted the vessel to attain a speed of approximately 6 knots.
Unfortunately, the steam conduits on the Civetta exploded while being tested. Because of this misfortune, the police banned any further testing. The explosion was not caused though by the tested propeller as many believed at the time.
The Paddlewheel Problem
By the early 1800s steamships were coming into common usage. The first steamship to cross the Atlantic was the SS Savannah, an American hybrid sailing ship/sidewheel steamer built-in 1818. She made the crossing in 1819 — mostly under the power of sail — the steam-powered paddlewheel contributed only a small proportion of her propulsion. It turns out that paddlewheels on ocean-going vessels had a problem.
Paddlewheels work well on calm water surfaces but are inefficient for rough ocean voyages. Rough waves rocking the ship result in one of the ship’s paddlewheels being out of the water half the time and spinning against the air instead of biting the water and propelling the vessel. What was needed was a propulsion system that stayed in the water under rough oceangoing conditions.
The SS Archimedes
Recognizing the limitations of paddlewheels on steamships, a race was on to develop an effective screw propulsion system. Many patents for such a system were taken out, few reaching the testing stage and fewer still offering promise. Efforts focussed on modifying the Archimedes screw for maritime use were however promising.
One inventor, Francis Pettit Smith (1808 –1874), was able to develop a test model that worked well enough for him to convince investors to establish a new company named the “Ship Propeller Company”.
The new company committed itself to build the ocean-going SS Archimedes, a 237-ton, 125-feet long vessel of 22.5 -feet beam. While still a hybrid vessel that carried sail, she also carried a steam-powered screw propeller (most marine propellers today are screw propellers) that delivered approximately 60 hp.
For all her technical success, Smith and his investors lost heavily – some £50,000 in money of the day, worth tens of millions in the 21st Century. The Royal Navy did not purchase her, as Smith had hoped, and she was sold on by the Ship Propeller Company. She was to suffer the indignity of having her engines removed and converted to a sailing vessel.
Before her ignominious end though the SS Archimedes was loaned for further tests of its new propeller propulsion system to the Great Western Steamship Company. The company was constructing the world’s largest steamship, the SS Great Britain. Impressed by the achievements of the SS Archimedes, the lead engineer on the Great Britain project was keen to explore the screw propeller’s potential.
In the end, following a series of tests of different propeller types, it was decided to fit Great Britain with a four-bladed type designed by Smith. When launched in 1843, Great Britain was by far the largest vessel afloat and she brought new levels of speed and comfort to transatlantic crossings.
Today the SS Great Britain can still be visited at Bristol, England where she has been preserved for exhibition as a museum ship.
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