Unique rotating funnel sail helps ships save fuel

What is a rotor sail? How does this rotating funnel-shaped sail save fuel? Let's find out!

An oil tanker at sea is to be fitted with a type of "rotating sail" invented nearly a century ago, in a 'revolutionary move' that could lead to more environmentally friendly tankers around the world.

These unusual sails are rotating masts fixed to the deck of a ship that interact with the wind to create forward thrust. The experiment is supported by Maersk, one of the world's largest shipping companies and the shipping arm of Shell.

International shipping largely uses highly polluting 'bunker' fuel and the industry is under increasing pressure to play its part in tackling climate change by reducing emissions. Technologies being explored to cut pollution include kites, batteries or the use of biofuels. And that's where the rotor blades come in.

 

Norsepower in Finland has developed a funnel-shaped sail called the Rotor Sail that helps ships take advantage of wind power at sea, reducing fuel consumption and emissions.

The Rotor Sail is a tall, rigid circular structure that acts like a sail made of canvas and polyester. This sail can rotate around a vertical axis.

As the wind blows, the airflow accelerates on one side of the circular sail, while the other side decelerates, creating a difference in speed and pressure between the airflows on the two sides, causing the rotor sail to rotate. This phenomenon is called the Magnus effect.

Norsepower revealed that their rotor sail design was inspired by the technology of a German engineer Anton Flettner in his transatlantic journey introduced nearly a century ago.

Norsepower's rotor sail is designed to be easily installed on existing ships, providing an additional source of power while reducing carbon emissions.

According to Norsepower's estimates, the two rotor sails could help the MV Delphine, which is due to be built in 2018, reduce fuel and emissions by 10%.

Norsepower is now expanding production in the hope that the rotor sail will help reduce carbon from the shipping industry.