Rotor Sail technology

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Rotor Sail technology - Cut fuel consumption by up to 30%

In today’s maritime industry, solutions that lower operational costs and reduce greenhouse gas (GHG) emissions are more important than ever. Wärtsilä is an authorised seller and servicing partner of the Anemoi Rotor Sail System, an innovative and proven energy saving technology for the shipping industry, harnessing the wind to provide auxiliary propulsion to vessels. The system can reduce fuel consumption and associated GHG emissions by up to 30%.

The Magnus effect - The technology behind the efficiency

Thrust is created by rotation in an air flow that results in a difference in pressure on the aft and forward of the rotor.

Thrust depends on wind angle and wind speed, the maximum thrust is created when the wind direction is just after the beam. 


  • Cut fuel consumption and associated emissions by up to 30%
  • Supports the achievement of regulatory compliance for EEDI, EEXI & CII
  • Wind ready concept. Pre-installed infrastructure to allow sails to be added to meet ongoing CII emission reductions
  • Flexible systems to suit the vessel (Fixed, Rail system and Folding system)
  • Can be adjusted for a variety of weather conditions
  • Can be redeployed between vessels as driven by business requirements
  • Ex-rating (Tankers/Gas carriers)
  • Integrated lifecycle service and support for the vessel’s entire lifespan

Equipment and location 

1. Wind sensor
2. Electrical & control system
3. Electrical hardware
4. Deployment system (Fixed system pictured)

5. Foundations
6. Rotor sails
7. Upper bearing
8. Steel tower

  9. Electric drive
10. Lower bearing
11. Composite rotor

Vessel applications

Rotor Sails are suitable for most vessel types, including newbuild and retrofit, Bulk Carriers (geared and gearless), Tankers, LNG and LPG Carriers, Ferries, and RoRos.
The Anemoi Rotor Sail System supplied by Wartsila is comprised of the Rotor Sail, the Foundation, Deployment System (if required), wind sensors and Electrical and Control system. 

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