Portuguese 
Danish Giant Partners with British Anemoi to Install Vertical Rotor at the Bow of Cargo Ship. Equipment Costs Between $600,000 and $1.2 Million, Can Save About 1 Ton of Fuel Per Day, and Introduces Ancient Technology to an Industry Pressured to Cut Emissions
Maersk, the second-largest container shipping company in the world, has decided to test a solution that seems counterintuitive for an industry dominated by giant engines: utilizing wind power again. The company has reached an agreement to install a rotor sail that measures 35 meters in height on a mid-sized container ship to assess whether the technology can significantly reduce fuel consumption and emissions, according to reports from the Financial Times.
However, the sail will not have fabric, ropes, or the traditional shape associated with old sailing ships. The equipment developed by the British Anemoi will consist of a large, vertically rotating cylinder, installed at the front of the ship.
As the wind flows around the rotating structure, the so-called Magnus effect creates an additional force capable of helping to propel the vessel.
-
Brazilian Helicopter Carrier Atlântico Sails Over 730 km Offshore with Two Frigates, Reaching the Rio Grande Rise for the First Time
-
U.S. Port to Invest $642 Million to Create Marine Space, Expand Maneuvering Areas by Up to 334 Feet, Allowing 1,312-Foot Ships to Turn Where They Currently Face Restrictions
-
TechOcean Announces 15 Positions for Offshore Operations, Docking, and Onshore Base in Macaé, Offering Roles for Welders, Pipefitters, Inspectors, and IRATA Professionals
-
Gás Sul Terminal to Be Leased by Âmbar from J&F Group, Capable of Regasifying 15 Million Cubic Meters Per Day in Santa Catarina
Thus, the engines will continue to be responsible for the main propulsion. However, when conditions are favorable, the wind could contribute to part of the effort.
Estimates cited by the FT suggest that modern wind propulsion systems could provide fuel savings of between 5% and 25%, depending primarily on the ship and the route.
Moreover, this initiative comes at a time when the shipping industry faces increasing pressure to reduce emissions. The sector accounts for about 3% of global carbon emissions, while new regulations begin to make fuel and CO₂ even more expensive.
35-Meter Sail Will Stand Upright at the Bow and Does Not Resemble Structures of Old Sailing Ships
The equipment chosen by Maersk has little in common with the classic image of a white sail filled with wind.
In practice, it is a 35-meter cylindrical rotor that will be installed vertically at the front of the container ship.
Additionally, the structure rotates during navigation.
It is this rotation that allows wind to be converted into useful force for propulsion.
The physical phenomenon is known as the Magnus effect. When an object rotates within a flow of air, pressure differences arise around its surface.
As a result, a force perpendicular to the wind emerges.
In the case of a ship, engineers leverage this force to help propel thousands of tons across the ocean.
Therefore, the technology does not attempt to turn a cargo ship back into a sailing vessel.
Instead, it adds a second source of propulsion that works alongside conventional engines.
Engine Continues to Operate, but Wind Becomes Part of the Work
The economic principle is simple.
A container ship must constantly overcome the resistance of water and air to maintain a certain speed.
Typically, its engines provide nearly all the necessary power.
However, with the rotor operating, part of that force comes from the wind.
As a result, in certain conditions, the engine can consume less fuel to maintain the same displacement.
This reduction may seem small on a single day. However, commercial ships spend hundreds of days sailing over their operational lifespan.
Thus, daily savings can accumulate over thousands of kilometers.
The technology has also been designed to operate in harsh conditions. According to Anemoi, the rotors can function with winds of up to 35 meters per second, approximately 126 km/h.
Still, this value represents an operational limit and not necessarily the ideal condition for maximum fuel savings.
Each Rotor Can Save About 1 Ton of Fuel and 3 Tons of CO₂ per Day
The numbers presented by the manufacturer help explain why shipowners have started to take a closer look at the technology.
According to estimates from Anemoi cited by the Financial Times, each rotor can save approximately 1 ton of fuel per day.
At the same time, the associated reduction can reach about 3 tons of CO₂ daily per sail.
However, these values do not guarantee savings for all voyages.
Wind direction, intensity, route, ship speed, and the vessel’s own design directly influence performance.
Additionally, the manufacturer typically installs its equipment in groups of three to five rotors.
Therefore, the scale of the system can vary considerably from one ship to another.
In the case of Maersk’s pilot program, however, the company will start with one rotor sail.
This way, it will be able to measure the actual performance before deciding whether to expand the technology to other container ships.
Savings Can Vary from 5% to 25%, and the Chosen Route Makes a Huge Difference
The range of estimates shows that installing a sail does not automatically produce the same result on all ships.
Experts cited by the FT estimate that wind propulsion technologies can generate fuel savings between 5% and 25%, depending on the vessel and the route.
In particularly favorable conditions, the gain may even exceed this range.
This difference occurs because wind is not equally available on all routes.
A ship that repeatedly traverses an area with strong, favorable winds can take much better advantage of the equipment.
On the other hand, a vessel operating on less suitable routes may experience considerably lower savings.
This is precisely where container ships have an important advantage.
Predictable Routes Allow Choosing Where the Wind Can Yield More Money
Large container companies typically operate regular services.
The ships repeat certain routes, visit familiar ports, and follow relatively predictable schedules.
This allows the company to study years of meteorological data even before installing equipment.
It can analyze the historical wind direction, average speed, travel time, and the operational speed of the cargo ship.
Then, it can identify which routes offer the greatest potential.
In this way, wind becomes more than just a meteorological variable.
It also factors into the financial mathematics of the voyage.
Almost the entire deck of a container ship is already occupied
Despite this advantage, there is a significant physical obstacle.
Just observe a large container ship to understand it.
Practically all available surface area above the deck is used for stacking containers.
On some ships, containers form real metallic buildings on top of the vessel.
Any space used by another structure can interfere with cargo transport capacity or crane operations during a port call.
Therefore, installing a 35-meter-high sail does not simply involve choosing an empty spot and fixing it there.
The lack of space is one of the reasons why container ships have not yet led the adoption of modern wind propulsion systems.
Tankers, for example, offer much more free area above the deck.
Consequently, manufacturers have been able to advance first in this type of vessel.
Maersk will have to prove that the sail saves fuel without hindering the cargo
This detail turns the test into something greater than just a demonstration of physics.
Maersk needs to determine whether the equipment can generate savings without compromising what makes the ship commercially viable.
A container ship needs to transport boxes.
Additionally, it needs to dock at terminals, position itself along the quay, and allow huge cranes to quickly reach its cargo.
Any system installed on the deck needs to coexist with this operation.
Therefore, the Anemoi sail will remain fixed and vertical at the bow of the chosen ship.
The manufacturer has other solutions that can fold during certain operations.
However, this will not be the configuration for the first test.
Each sail costs between US$ 600,000 and US$ 1.2 million even before installation
The force of the wind may be free.
The equipment needed to take advantage of it, however, is not.
Each rotor produced by Anemoi costs approximately US$ 600,000 to US$ 1.2 million.
And this amount does not include installation.
Since some systems use three to five units, a complete installation may require several million dollars.
Therefore, reducing fuel consumption is not enough.
The savings need to be significant enough to recover the investment within a commercially acceptable timeframe.
It is at this point that a less visible obstacle arises compared to the lack of deck space.
The biggest hurdle may lie in contracts, not technology
According to experts consulted by the Financial Times, the main barrier currently may be more commercial than technical.
The problem arises from the way many ships are operated.
Often, the vessel owner pays for the installation of new equipment.
However, those footing the fuel bill may be the charterer.
In this scenario, the owner spends millions to install the rotors, while another company captures much of the savings from reduced consumption.
Additionally, the time required to recoup the investment may exceed the duration of a typical charter contract.
Thus, the incentives are not naturally aligned.
This situation helps explain why a technology may work technically but still take time to gain market acceptance.
Higher fuel costs begin to change the math of sails
On the other hand, some factors have started to favor wind propulsion.
The first is the price of fuel.
The higher the cost of fueling a ship, the greater the financial value of each ton saved.
Furthermore, environmental regulations are starting to turn emissions into more direct expenses.
Consequently, the savings involve more than just fuel.
They can also impact carbon-related costs.
Therefore, a technology that seemed expensive in a cheap fuel scenario can become attractive when operational costs rise.
European Union already charges the shipping sector for part of the emissions
Since 2024, the European Union has included maritime transport in its emissions trading system.
Additionally, the bloc has introduced regulations requiring a reduction in the emissions intensity of fuels used by ship owners.
In practice, this adds another economic incentive.
If a company burns less fuel, it reduces emissions.
Consequently, it can also lower some of the costs associated with carbon.
Meanwhile, the International Maritime Organization continues to discuss new global regulations for the sector.
Thus, technologies capable of reducing consumption without requiring a complete engine overhaul are gaining traction.
About 110 commercial ships already use modern wind propulsion systems
Maersk is not engaging in a technology that exists only in the lab.
According to data cited by the FT, there are approximately 110 commercial installations on large vessels.
Moreover, another 80 to 90 units are on order.
There are also dozens of projects in development.
In recent years, the number of installations has grown rapidly.
However, most of these systems have appeared in segments with more deck space available.
Tankers lead this movement.
Bulk carriers and car transporters have also started to adopt different technologies.
Now, Maersk wants to find out if the same advancement can reach the container ships.
Wind returns to ships, but now connected to sensors, automation, and data
The idea of using wind to cross oceans has existed for thousands of years.
However, the current method is completely different.
The rotor does not rely on sailors pulling ropes or adjusting huge pieces of fabric.
Instead, modern systems control its operation and leverage information about wind, speed, and route.
In this way, an ancient technology functions in conjunction with automation, weather forecasts, and digital navigation systems.
The cylinder rotates.
The Magnus effect generates force.
Thus, the motor can reduce some of the effort.
This combination illustrates why the return of sails does not represent a technological regression.
In reality, the industry is trying to combine a resource used for centuries with tools that simply did not exist on ancient sailboats.
Other systems use foldable wings and suction sails to pursue the same goal
Anemoi’s rotors represent just one of the available solutions.
Companies are also developing foldable sails, rigid wings, and suction systems, among other alternatives.
Each design tries to address similar problems in different ways.
The system needs to generate sufficient force.
At the same time, it cannot compromise stability, cargo, visibility, or port operation.
Moreover, it must withstand years of salt exposure, vibration, waves, and severe weather conditions.
Therefore, it is not enough to function under controlled testing.
The technology needs to remain viable after thousands of hours at sea.
Oil tankers are ahead because they offer more open deck space
The distribution of current installations shows how the ship’s architecture influences adoption.
Oil tankers have large deck areas without stacks of containers.
This way, engineers find more points where they can install rotors, wings, or sails without directly removing cargo capacity.
Container ships face a different situation.
Almost all upper space has a logistical function.
Additionally, cranes need to quickly move boxes during port calls.
Thus, the pilot from Maersk can answer an important question for the entire sector:
Is it possible to make wind propulsion work economically precisely on the type of ship where space is most contested?
Fixed routes can transform wind forecast into an investment tool
If the answer is positive, adoption will likely not happen in the same way across the fleet.
Some routes offer better conditions than others.
Therefore, companies can analyze their services and select specific vessels to receive the systems.
A route with historically favorable winds can yield a faster return.
Another may not justify the investment.
In this scenario, meteorological data gains a new function.
They stop being solely about safely planning the journey.
They can also help determine where it makes sense to invest millions of dollars in propulsion equipment.
Maersk wants to know if the solution works for a much larger fleet
The company sees the pilot as an opportunity to gain practical experience.
Additionally, it wants to assess the technology’s relevance for its own fleet and for container transport more broadly.
This point is crucial.
The goal is not merely to prove that a cylinder can generate force using wind.
This physical principle is already established.
The question is commercial and operational.
How much fuel will actually be saved?
How will the equipment perform during the voyages?
What will the impact be on the terminals?
How much will it cost to maintain the system?
And, most importantly, how long will it take to recover the investment?
Testing Gains Importance as Maersk Operates at the Center of Global Trade
The size of the company increases the significance of the pilot.
Maersk holds the position of the second largest container shipping company in the world.
Therefore, any technology that demonstrates consistent results within its operation gains a global showcase.
Moreover, container ships form a crucial part of international supply chains.
They transport electronics, machinery, clothing, food, industrial components, and thousands of other products across continents.
Thus, a seemingly modest reduction in fuel per trip can take on another dimension when applied repeatedly across a large fleet.
Still, it will first be necessary to prove that the solution works precisely where space is so valuable.
Ships and Ports Must Also Coexist with Ever-Larger Structures
Integration does not end when the vessel reaches its destination.
Container ships need to dock at terminals equipped with enormous cranes.
Therefore, any new structure installed above the deck must also be considered during port operations.
This challenge becomes more critical as maritime infrastructure itself undergoes significant transformations.
In various countries, new port areas are being developed to accommodate larger ships and operations.
In the case of Maersk’s sail, the choice of bow seeks to integrate the rotor into the ship without hindering the vessel’s primary function.
However, real tests will be crucial to reveal limitations that designs and simulations may not always anticipate.
Technology Can Reduce Fuel Consumption Without Replacing the Entire Engine
An important advantage lies precisely in the possibility of adaptation.
The system does not require an immediate abandonment of existing engines.
Instead, the rotor acts as a supplement.
Therefore, the company can install the technology on an already built ship and harness part of the wind energy during certain voyages.
This retrofit model can accelerate adoption if the financial results are positive.
After all, the global fleet consists of thousands of vessels that will continue to operate for many years.
Expecting all these ships to be replaced by completely new designs would take decades.
That is why solutions capable of reducing emissions on existing vessels attract interest.
Maritime Decarbonization Will Likely Depend on Multiple Technologies Simultaneously
Wind propulsion does not appear as a singular solution for maritime transport emissions.
The sector is also testing alternative fuels, new engines, hull optimization, digital systems, and various ways to reduce drag.
Thus, the future will likely involve a combination.
A ship can use fuel with lower carbon intensity.
In addition, it can sail at optimized speeds.
At the same time, digital systems can select more efficient routes.
Finally, when there is favorable wind, a modern sail can take some of the load off the engines.
In this way, small improvements accumulate.
This reasoning helps explain why a technology capable of reducing consumption even by a fraction can still hold significant value.
Industry is already building gigantic vessels for the new energy infrastructure
While companies seek to reduce emissions from existing cargo ships, the maritime sector is also developing specialized vessels for a more electrified economy.
Recent projects include giant ships capable of working at thousands of meters deep, transporting tens of thousands of tons of cables, and connecting offshore wind farms.
At the same time, Maersk is testing a much simpler approach in principle: harnessing the air that already flows past the ship.
The two trends show how maritime engineering is evolving in different directions.
On one side, extremely specialized vessels are emerging.
On the other, old technologies are returning completely redesigned.
Pressure to reduce emissions increases because maritime transport accounts for around 3% of global carbon
The scale of the challenge helps explain the number of alternatives in development.
Maritime transport accounts for approximately 3% of annual global carbon emissions.
This share may seem small when compared to the overall economy.
However, it is a fundamental industry for international trade.
Moreover, replacing fuels in ocean-going ships presents particular challenges.
A vessel needs to carry enough energy to cover vast distances.
The fuel also needs to be available at various ports.
Therefore, any solution that reduces the amount needed during the journey can assist while low-carbon fuels are still scaling up.
Investment of up to US$1.2 million per rotor must compete with other solutions
The final decision will still depend on the financial calculation.
A rotor costs between US$600,000 and US$1.2 million before installation.
Therefore, shipowners need to compare this investment with other available alternatives.
If a hull improvement provides a quicker return, it may take priority.
If a new fuel becomes competitive, the strategy changes as well.
On the other hand, if fuel and carbon prices rise, the value of each ton saved increases.
In this way, a technology considered expensive today may become much more attractive a few years later.
That is why Maersk needs real data.
The pilot will help replace projections with operational experience.
The physics is known, but the challenge now is to prove that the math adds up
The Magnus effect is not a recent discovery.
Nor is there any doubt that wind can generate force on a rotating structure.
The uncertainty lies in another area.
How much is that force worth financially on a modern container ship?
To respond, the company must consider saved fuel, avoided emissions, equipment costs, maintenance, operational interference, and lifespan.
Additionally, it needs to analyze the route.
An excellent result in one maritime corridor does not guarantee the same performance in another.
Therefore, the pilot represents an attempt to transform known physics into a data-driven investment decision.
From 110 Current Installations to a Possible New Generation of Container Ships
The wind propulsion market is still small compared to the global shipping fleet.
However, the numbers indicate growth.
There are approximately 110 commercial installations, another 80 to 90 on order, and dozens of projects in development.
Moreover, installations have rapidly increased in recent years.
So far, however, container ships have lagged behind.
The lack of space explains much of this difference.
Thus, Maersk’s project could serve as an important test to determine whether the segment can keep pace with tankers, bulk carriers, and car transporters in this trend.
Free Wind Meets an Industry Where Every Square Meter Costs Money
This may be the most interesting contradiction of the project.
The energy source is free.
Wind crosses the ocean whether the ship harnesses it or not.
However, capturing this energy requires a structure that costs up to US$ 1.2 million per unit and occupies extremely valuable space.
In a container ship, this detail weighs even more.
Every available square meter can impact the capacity to carry goods.
Therefore, Maersk needs to find a balance.
The sail must be large enough to generate savings.
However, it cannot significantly compromise the vessel’s commercial function.
After Centuries of Evolution, Modern Ships Look to the Wind Again
The historical irony is evident.
For thousands of years, vessels depended on the wind because there was no alternative.
Later, steam engines and subsequently fossil fuel-powered engines allowed for faster, more predictable journeys.
Thus, large commercial ships almost entirely abandoned sails.
Now, the pressure to reduce fuel usage and emissions is causing the industry to reconsider the same resource.
However, no one intends to return to the old model.
The traditional sail is being replaced by a 35-meter cylinder controlled by modern technology.
Wind does not replace the engine.
Instead, it helps the engine work less.
Maersk Tests Whether an Old Idea Can Survive the Math of Modern Transport
In the end, the pilot will be determined by numbers.
The rotor will be 35 meters tall.
Each piece of Anemoi equipment costs between US$ 600,000 and US$ 1.2 million before installation.
The manufacturer estimates savings of about 1 ton of fuel and 3 tons of CO₂ per sail daily, depending on conditions.
Meanwhile, experts calculate that wind propulsion can reduce consumption by 5% to 25% depending on the ship and the route.
Now, the second-largest container shipping company in the world needs to determine whether these gains justify the investment, maintenance, and, most importantly, the space taken up on a deck designed to carry as many boxes as possible.
If the numbers add up, an industry that has spent over a century replacing sails with engines may reach an intriguing conclusion:
the future of ships might once again include a force that propelled them long before the invention of modern fuels.
Do you believe that modern 35-meter sails could become common on container ships, or will costs and deck space constraints continue to hinder the scalability of this technology?
