The World's Strangest Boats: Sailboats Without Sails

Interesting Engineering

It seems odd to think not all sailboats have a sail.

Sailboats function on the principle of wind propulsion. Typical sailboats harness the wind trapped behind large sails. However, several engineers are changing the way people look at traditional sailing.

In 1920, German engineer Anton Flettner proposed a revolutionary idea to change the basic foundation upon which sailboats were built. Flettner created a unique sailboat which used large rotating pillars in place of sails.  The 50-ft tall (15 m) pillars rotated at a high velocity with 50 horsepower engines.

The pillars utilize the ships excess power to spin them and take advantage of the wind as an auxiliary power source. This increases the speed of the ship while maintaining horsepower. The newly refined 'sail' was dubbed the Flettner rotor.

old-shipRotor Towers Acting as Secondary Propulsion Source for the World's First Rotor Tower Sailboat: The Barbara [Image Source: Shipping Wonders of the World]

How does the ship move?

The pillars take advantage of a physical phenomenon known as the Magnus Effect. Rotating pillars cause air to rapidly spin around the cylinders. An object traveling through the atmosphere causes air to separate on both sides of the obstruction. On one side. the spin travels in the same direction of the wind and pulls the wind down towards the opposing side.

Newton's third law famously describes for every action,there is an equal an opposite reaction. As such, the redirected airflow pushes down and therefore causes the object to be pushed up.

Modern Application

The Magnus Effect offers more than just a physical concept. Enercon, a ship building company, makes use of the effect to power incredibly fuel-efficient ships. The ship makes use of four Flettner rotors. The ship, the "E-Ship 1" is designed with fuel efficiency as key.

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enecronE-Ship 1 [Image Source: Enercon]

The ship entered service in 2010 and since has proven Flettner rotors are a viable alternative to provide an efficient power source to commercial ships. Favorable weather conditions provide fuel savings of up to 15 percent. The E-Ship 1 could perhaps become part of the next generation of shipping transportation.

The ship was designed so that if wind blows from either side of the ship, the pillars can be spun to harness the energy.

Innovation does not necessarily require high-tech solutions. Sometimes, taking a look back through history to see what used to work can reveal simplistic solutions that are often overlooked. Fletcher rotors provide a viable, more fuel-efficient alternative to massive shipping vessels.


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