Wind Challenger Next-Generation Wind Powered Vessel

Mitsui O.S.K. Lines (MOL) has developed the Wind Challenger, which converts wind energy directly to a vessel propulsion force through an extensive use of the latest technologies. Once again casting a spotlight on the wind as clean and unlimited source of energy, we aim to drastically reduce greenhouse gas emissions by reviving sail vessels based on a whole new idea. We are planning to commence operation of the first large commercial vessel with Wind Challenger in 2022.

MOL's Wind Challenger Project

Find out more about the Wind Challenger project and the solutions that can be achieved through use of the Wind Challenger.

What is Wind Challenger?

The International Maritime Organization (IMO) adopted greenhouse gas (GHG) reduction strategies in April 2018, setting goals such as cutting GHG emissions by 50% by 2050 compared to 2008 levels, amidst a growing movement toward preventing global warming that was gaining further attention after the Paris Agreement. In recent years, the movement towards carbon neutrality has been gathering momentum around the world.

Wind Challenger utilizes wind power, which is a renewable energy, as a propulsion force for a vessel by the sail. While current large commercial vessels rely almost solely on fossil fuels for their propulsion, Wind Challenger adds wind power directly to its propulsion force to reduce the consumption of fossil fuels without changing the vessel speed. By installing and effectively using a sail, i.e. a traditional sailing vessel technique, and evolving it as much as possible by leveraging the latest technologies, we have been successful in reducing the fuel consumption of a large cargo vessel and drastically reducing its GHG emissions.

GHG Emission Reduction due to Installation of a Sail

GHG Emission Reduction due to Installation of a Sail

In this project, we conducted computational fluid dynamics (CFD) modeling and wind tunnel experiments to estimate the propulsion force generated by a sail and generated polar diagrams.

We multiplied the polar diagrams by the wind conditions and vessel velocities on the expected navigation route to calculate the overall wind power assist (assisted propulsion force) on the navigation route and compared it against the case without assisted propulsion force by the sail. The assisted propulsion force was converted into fuel consumption taking into account the vessel size. This translated to 5% reduction in the fuel consumption for the Japan to Australia route, and 8% for the Japan to North America west coast route in case of 100k tons bulk carrier.

Features of Wind Challenger Sail

It is important that the sail shall be light enough so it would not affect the amount of cargo that the vessel can carry. We employed glass fiber reinforced plastic (GFRP) as the sail material.

This enabled us to make the dimensions of the sail large to maximize the propulsion force it generates. It also minimized its impact on the vessel balance, which significantly improves the operational safety.

A sail vessel needs to have its sail direction and tension adjusted according to the wind conditions (speed and direction), which requires deep understanding and experiences. Wind Challenger automated the sail control so that any crew member can maximize the use of the wind easily. The sail detects the speed and direction of the wind by sensors. The sail is extended if the wind is not strong, and shrunk if the wind is strong. The sail is also automatically rotated.

Differences between Engine Vessel and Sail Vessel

Modern large vessels are powered by engines. We introduce differences between engine vessels and sail vessels in this section.

Principle of Propulsion for Sail Vessels

Principle of Propulsion for Sail Vessels

A sail vessel receives the wind power on its sail to generate propulsion force. The sail vessel does not generate any GHG because its source of propulsion force, wind, is a natural energy. Therefore, the sail vessel has a small environmental load. However, the wind speed and direction have a major impact on the vessel's speed and direction, which makes its scheduling uncertain and maneuvering difficult. Sail vessels are not used for commercial vessels for this reason. While sail vessels were used as a maritime transportation method since ancient times, they gradually fell out of favor with the advent of steam and engine vessels due to the overwhelming differences in the propulsion force and practicality.

Principle of Propulsion for Engine Vessels

Principle of Propulsion for Engine Vessels

An engine vessel generally uses petroleum (heavy oil) as its fuel to drive an engine which rotates its propeller to generate propulsion force. A large commercial vessel is equipped with a large diesel engine to generate huge propulsion force. However, the use of heavy oil as main fuel, which is a fossil fuel, makes it difficult to reduce emissions of GHG such as carbon dioxide.

Applicable Vessels and Other Aspects of Sail Vessels

We are currently working on a project to install the sail on 90k tons coal carrier to be delivered in 2022. We are also considering the use of sails on bulk carriers, tankers and LNG carriers of different sizes. However, car carriers are not suitable to install because of their high freeboard (height of a vessel above the sea level).


Wind Challenger Service Overview

download materials about outlines the Wind Challenger, including its structure and how it is propelled by wind.

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Steps of Installation

We first conduct interviews with the client to discover their needs, then propose the most suitable vessel specifications, such as the type of vessel and ports of call where the Wind Challenger will be installed. We also provide consultation services for maintenance and other aspects after installation.

Steps of Installation

Post Installation Support and Maintenance

Post installation support and maintenance

Mechanical components (hydraulic pumps for sail expansion and electric motors for sail rotation) at the base of the rigid sail* require maintenance based on operating hours, in the same way as for other mechanical components. The steel parts of the sail are protected by paint, however, they are to be re-painted at a dock if rusting becomes an issue over the years. The FRP components are basically maintenance-free. However, we believe that they require re-painting after a certain period of time to maintain their visual appeal as their colors fade with exposure to ultraviolet light. * Rigid sail: Wing-shaped sail that does not change its shape.

Next-Generation Sail Vessel Case Studies

Wind Challenger

The hard sail system to be installed on the first Wind Challenger ship was finally completed.

Wind Challenger

As part of our greenhouse gas (GHG) emission reduction project, the first Wind Challenger is scheduled for completion.


Here are some frequently asked questions and answers about Wind Challengers.

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Terms for Wind Challengers, their associated equipment and basic knowledge are explained here.

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Wind Challenger

Please feel free to contact us about our Wind Challenger and associated services.

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