A rotor sails or flettner rotor is a clean cylinder with disc quit plates that is spun alongside its lengthy axis and, as air passes at proper angles throughout it, the Magnus effect reasons an aerodynamic pressure to be generated within side the route perpendicular to each the lengthy axis and the route of airflow. In a rotor deliver the rotors stand vertically and raise is generated at proper angles to the wind, to force the deliver forwards. In a rotor aircraft the rotor extends sideways in location of a wing and upwards carrying force is generated.


The first deliver that turned into used to increase the idea of the Flettner rotors turned into the Buckau evolved in Germany via way of means of the Germaniawerft. Alongside being certainly considered one among the biggest developers of the German U-boat submarines, it turned into concerned withinside the improvement and trying out of medical ideas. The group of designers that labored at the concept and oversaw the development of the rotors have been specialists within side the fields, and are famous names within side the aerodynamics and fluid mechanics industry.

Albert Betz (pioneered wind turbine technology), Anton Flettner (an professional aerospace engineer), Jakob Ackeret (Swiss aeronautic professional and fellow of the Royal Society), and Ludwig Prandtl (evolved numerous mathematical and analytical fashions of fluid mechanics) designed the rotor vessel which turned into constructed in 1924 The Buckau hired a twin-rotor device that measured 15 meters in peak and three meters in diameter. The vehicles used to rotate the rotor sails drew 37 kilowatts of electricity. Its first voyage turned into from Danzig (Gdansk in Poland) to Scotland in 1925, and then, later on, sailed to the Americas in 1926. However, the deliver turned into inefficient and had issue in mustering enough electricity to propel the craft at an ok speed. As a result, the assignment turned into finally scrapped and the notion turned into shelved.

Another German deliver, the Barbara, turned into constructed in 1926 that tried to apply a 3-rotor device to propel the craft. Built out of Bremen via way of means of the Weser shipyard, it turned into additionally scrapped because of assignment delays and difficulties.

Eventually, hobby renewed within side the Flettner structures for the duration of the 1980s, and research have been taken up to research the feasibility of any such propulsion device.

Modern Vessels

  • Enercon released the hybrid rotor deliver E-Ship 1 on 2 August 2008. From 2010, it’s been used to move the agency’s turbine merchandise and different equipment. Enercon claim “operational gas financial savings of as much as 25% in comparison to same-sized traditional freight vessels.”
  • The University of Flensburg is growing the Flensburg catamaran or Uni-Cat Flensburg, a rotor-pushed catamaran.
  • In 2007, Stephen H. Salter and John Latham proposed the constructing of 1,500 robot rotor ships to mitigate worldwide warming. The ships could spray seawater into the air to decorate cloud reflectivity. A prototype rotor deliver changed into examined on Discovery Project Earth. The rotors had been fabricated from carbon fibre and had been connected to a retrofitted trimaran and propelled the vessel stably via the water at a pace of six knots.[citation needed]
  • In 2009, Wärtsilä proposed a cruiseferry that might utilise Flettner rotors as a way of decreasing gas consumption. The Finnish ferry operator Viking Line followed the idea, with MS Viking Grace constructed in 2011–2012, first of all with out rotors. A rotor machine changed into retrofitted in 2018.
  • In 2014 and 2015, Norsepower set up dual rotor sails on Finnish delivery agency Bore’s RoRo vessel M/V Estraden. In May 2018, the 1996 constructed shipment deliver Fehn Pollux of the German-primarily based totally Fehn Shipmanagement (Leer) changed into equipped with an 18m lengthy Flettner rotor of the EcoFlettner kind on the front.
  • In 2018, Norsepower deployed rotor sails with the world’s largest delivery agency, Maersk. The Maersk Pelican, an LR2 elegance tanker, has been equipped with  Norsepower Rotor Sails.
  • The MV Afros (IMO 9746803) bulk provider has operated 4 movable rotors over a yr with nice results.
  • In 2021, Norsepower set up 5 tilting rotor sails onto a Vale-operated iron ore provider to permit maneuvering underneath bridges.

Working and Principle

The Rotor Sail generation is primarily based totally on the Magnus effect. A rotor or Flettner deliver is designed to apply the Magnus effect for propulsion. The Magnus effect is a pressure appearing on a spinning frame in a transferring airstream, which acts perpendicular to each the course of the airstream and of the rotor axis. A Magnus rotor used to propel a deliver is known as a rotor sail and is set up with its axis vertical. When the wind blows from the side, the Magnus effect creates a ahead thrust. Thus, as with all cruising deliver, a rotor deliver can best pass forwards while there’s a wind blowing. The maximum not unusual place shape of rotor sail is the Flettner rotor.

Due to the association of forces, a rotor deliver is capable of sail towards the wind than a traditional cruising deliver. Other blessings consist of the convenience of manage from sheltered navigation stations and the dearth of furling necessities in heavy weather.

However, if the deliver adjustments tack in order that the wind comes from the alternative side, then the course of rotation have to be reversed or the deliver could be pushed backwards.

The wind does now no longer strength the rotor itself, which have to have its very own strength supply. Like different cruising ships, rotor ships frequently have a small traditional propeller as well, to offer ease of maneuverability and ahead propulsion at sluggish speeds and while the wind isn’t always blowing or the rotor is stopped. In a hybrid rotor deliver the propeller is the number one supply of propulsion, even as the rotor serves to dump it and as a result growth universal gas economy. Rotor sails were stated to generate 5-20% gas financial savings.

Efficiency of Rotor Sails

The rotor sail is stated to be 10 instances extra green than a traditional sail, growing extra raise with a smaller floor area. However, like traditional sails, it relies upon at the course of the wind, so is nice used as an auxiliary propulsion machine to complement an average gas-powered vessel.

Rotor Sails have validated improved vessel performance, decreasing gas consumption, bunker expenses and dangerous emissions. Compared to different wind propulsion technology, Rotor Sails provide a miles more thrust pressure to propel the deliver in step with rectangular meter of sail area. This approach they may be made extra fee correctly and with much less effect on vessel operation than conventional sails or wings.

Effect on Emission Control

The delivery enterprise debts for about 90% of global wide exchange and contributes round 3% of worldwide CO2 emissions. Although that is an extraordinarily low figure, worldwide exchange volumes are anticipated to upward thrust which can result in a growth in emissions except new ships getting into the marketplace are of an awful lot more performance and antique ships are made ‘cleaner’ via using novel technology. The International Maritime Organisation (IMO) predicted that during 2012, the delivery enterprise emitted 796 million tonnes of CO2 and therefore determined to introduce emission goals to align the delivery enterprise with the Paris Agreement, of which it’s miles presently exempt.

The degree goals are first of all to lessen Greenhouse Gas emissions through 40% (in comparison to 2008) through 2030 after which to pursue a 50% discount through 2050. To assist acquire those goals, the IMO has installed location measures inclusive of the Energy Efficiency Design Index (EEDI). Other projects inclusive of RightShip’s GHG score and Poseidon Principles were brought through different enterprise our bodies to force decarbonisation inside delivery.

Wind-assisted propulsion is a extra mature generation while in comparison to a few different technology and will be one of the feasible answers to assist fulfil expected EEXI necessities and decrease operational carbon intensity. In this experience EEXI (and probable extra operational measures) will be a using component in accelerating uptake of wind-assisted propulsion systems. Attention will want to be paid to the general regulatory framework to foster in addition improvement and implementation of this generation. 

The gas-saving overall performance of the Rotor Sail installations on every of those reference vessels has been measured and analyzed through impartial third-parties.


This technology additionally lessens the general power required to finish a voyage. As ships begin the use of options to fossil fuels, ships which are extra green might be extra aggressive within side the sector. This is important due to the fact that sustainable biofuels, electricity, hydrogen, and different fuels might be each restrained in delivery and costly.

What do you think about it? Give it a thought.

Authored By:- Cdt. Tanvi Dubey, TMI

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