Return of the Sailing Ships A Green Revolution for Seafaring

When Artur Sylwestrzak wants to demonstrate how well the wind drive works on his ship, he turns it off The contrast is noticeable, says the 37-year-old ship's captain.

Sylwestrzak is in command of the SC Connector, a 155 meter transport vessel that operates on the North Sea In September 2021, he remembers, he set sail from Rotterdam at night.

His destination was the port of Tananger, Norway, 421 nautical miles north as the crow flies When dawn broke, the wind was blowing at about 50 kilometers per hour.

According to Sylwestrzak, that's not much for an autumn day on the North Sea, but it was enough to propel the ship forward vigorously Two gigantic cylinders – so-called Flettner rotors – turned on the deck behind the command bridge.

The idea for this drive technology came from the German engineer Anton Flettner In 1924 he had such rotors installed on the schooner Buckau instead of sails.

The concept worked, but never caught on That could change with the SC Connector.

Its rotors have a diameter of five meters and, at 35 meters, are as high as a twelve-story building As soon as wind flows around them from the side, this generates a force in the direction of travel of the ship.

It's all about the rotation The physical mechanism behind this is the so-called Magnus effect.

It also comes into play when soccer players circle free kicks around defensive walls or tennis players topspin the ball down just behind the net Rotation is key.

As a result, the air flows faster past the surface of the ball on one side than on the other On the fast side, in turn, it detaches itself from the contour of the ball earlier than on the slow side.

This asymmetrical, so-called "boundary layer separation" bends the flow behind the ball to the side According to Newton's third law, there must be an equal, opposite force.

This force acts on the ball and pushes it to the other side The same happens on the rotors of the SC Connector.

Sylwestrzak gave the order to stop the rotors to demonstrate the technique to some guests on the bridge As soon as they came to a standstill, the ship ran only on its conventional propulsion system.

Sylwestrzak says his speed immediately dropped by about six kilometers per hour from 18 to 15 knots "When you're used to the speeds of cars or planes, it doesn't sound like much," he says.

But in seafaring there is a huge difference The actual benefit of the rotors is reflected in the fuel consumption.

According to the Finnish company Norsepower, the manufacturer of the rotors, the ship saved 4 6 tons of fuel and 14 tons of CO2 on the trip to Norway compared to a trip without the wind support.

On average, the technology ensures that the ship requires 25 percent less fuel The SC Connector could thus herald a new era in seafaring, in which wind drives may not replace ship engines, but at least support them.

In addition to the Connector, at least 21 large ships are currently in use that use the wind as a propulsion aid Not all have Flettner rotors.

The 235 meter long general cargo ship Shofu Maru has a 48 meter high so-called "wingsail" This tough but collapsible sail is made of fiber-reinforced plastic and can redirect airflow like an airplane wing to gain propulsion from the wind.

The cargo ship Ankie, in turn, is supported by two so-called "suction wings" These fixed sails have vents through which they draw in air, thereby also deflecting airflow and creating propulsion.

A 500 square meter kite is attached to the bow of the Ville de Bordeaux, a former transport ship for components of the Airbus A380, which pulls the ship across the seas when the wind is favorable And the Ariane Group, the manufacturer of the European launch vehicle, recently announced that equip their "Canopée" with four Wingsails this summer.

The ship is to transport parts of the Ariane 6 across the Atlantic to French Guiana to the European launch site near Kourou All these technologies should help shipping to reduce its greenhouse gas emissions.

It currently accounts for three percent of global CO2 emissions 15 percent of all nitrogen oxide emissions are said to come from ships' funnels.

It is estimated that these pollutant emissions could increase by 50 to 250 percent over the next thirty years To prevent this, parts of the shipping industry are now turning to a technology that is thousands of years old.

As early as the fourth millennium BC, as evidenced by depictions on ceramics, inhabitants of the Nile valley were equipping boats with sails The end of the sailors began in the 19th century.

Century, when coal-fired steamships and later diesel-powered ships came along Although large windjammers still transported goods across the oceans up until the middle of the 20th century, they too were replaced by faster motor ships that were independent of the wind.

In addition, the sailing ships were not suitable for crossing the Suez and Panama Canals They disappeared from commercial seafaring.

The breakthrough didn't materialize Your current comeback attempt isn't the first, however When oil prices skyrocketed 40 years ago during the Islamic Revolution in Iran and the First Gulf War, the American government started a research project for modern sailing concepts.

In addition, a handful of shipowners equipped their merchant ships with sails But the breakthrough did not come.

But this time it should work, if Gavin Allwright has his way When asked what should be different today than in the eighties, the Brit replies: "I wasn't there then.

" As is so often the case, there is a kernel of truth in this joke Allwright founded the "International Windship Association" in 2014, whose declared goal is to promote wind propulsion in commercial shipping.

Allwright's personal goal seems more ambitious He wants to revolutionize seafaring.

It runs in his family His father was in the Navy and his wife's ancestors were Japanese shipbuilders and fishermen.

He used to travel a lot, he met poor fishermen in ports while yachts sailed by on the horizon "They could use the free energy of the wind, and the fishermen had to scrape together money for diesel – something is wrong there,” he thought at the time.

And then there is a personal motive His youngest son, 17, has a lung condition.

Ports are taboo for him because of the ship exhaust fumes, says Allwright "He can never accompany me on my business trips because he just can't breathe there.

" When he seriously answers the question of why wind-assisted seafaring could prevail this time, he mentions regulations 40 years ago, wind drives were interesting for economic reasons alone.

When oil prices fell again, the wind lost its appeal Today is different.

The International Maritime Organization of the United Nations stated in 2018, aiming to reduce greenhouse gas emissions from shipping by 70 percent by 2050 From 2024, the European Union wants to include maritime shipping in emissions certificate trading – large ships that call at European ports should pay for their emissions.

In addition, understanding of climate protection is also gaining ground in the shipping companies “People my age are in the key posts there, people in their early 50s,” says Allwright.

This generation has already grown up with an awareness of environmental protection Above all, technology is more advanced today than it was in the 1980s.

In his Windship Association alone there are more than 110 companies working on wind drives Nevertheless, many technical questions have not yet been clarified.

Because even if the physical principles with which the rotors, Sails and kites that drive ships are well known and basically simple, so the devil – as is usual in engineering – is in the details Today's systems usually contribute five to 15 percent to the ship's propulsion averaged over longer periods of time.

The engine has to do the rest With the European research project "Optiwise", scientists want to increase the proportion of wind energy to between 30 and 70 percent.

To do this, they have to rethink the design of ships Propeller and engine need rethinking Of the 22 wind-assisted ships, 16 were not originally built to be powered by sails or rotors, so they can only gain limited thrust from the wind.

"Due to the wind propulsion, the ships are exposed to lateral forces", explains project coordinator Rogier Eggers from the Dutch research company Marin They would have to compensate for this with the oar, which in turn increases the water resistance.

Also, her hull shape is not designed to lean to the side, as is the case with wind propulsion Aerodynamics also play a role.

"The more sails or Flettner rotors you build on the deck, the more they influence each other," says Eggers That leads to losses.

A crucial point is also the conventional ship engine It runs most efficiently at a given load.

But this load decreases when sails provide additional propulsion So you need concepts for the engine room with which you can adjust the performance of the engine and still operate it efficiently.

The ship's propeller must also be reconsidered, because if the ship were to sail solely with wind power, the stationary screw would generate a great deal of resistance The experts want to clarify these questions within three years.

To do this, they calculate the forces that act on the ships on the computer, test true-to-scale models in flow channels and put entire crews in simulated ship bridges "This is how we see how the seafarers actually use the systems," says Eggers.

But no matter how well these are optimized, ultimately it also depends on the wind Although it blows on today's trade routes, ships will have to adjust their courses to make the most of it.

Artur Sylwestrzak, the captain of the SC Connector, is already doing this He derives suitable routes from weather forecasts.

Sometimes he deviates tens of nautical miles from the shortest route, which is the standard route for pure motor vessels He enjoys this additional task.

"I've had a passion for sailing since I was a kid," he says Planning the route according to the wind is exciting for him.

"The search space for the optimal route is large" But even the most experienced seafarers will eventually reach their limits when it comes to finding the optimal winds, as they must also observe the strict schedules of global trade This turns every route planning into a strategy game.

For example, it might be worth driving full speed ahead on the first day of an ocean crossing to catch up with favorable weather conditions But maybe a front is coming from behind and it would be better to wait.

Possibly the wind blows stronger far away from the direct route, which is why the ship should initially go in a completely different direction for some time "The search space for the optimal route is large," says Maxime Dupuy.

He works for the French company D-ICE Engineering, which develops, among other things, assistance systems for wind-assisted merchant ships This also includes algorithms that find the right routes.

The search includes weather forecasts There is also data about waves, the propulsion systems and consumption of the ship and the schedules.

"Our algorithm explores different paths and then spits out some results," says Dupuy The crew can then choose from these.

Since the weather forecasts are only really accurate for the next three to five days, the routes have to be adjusted again and again along the way Gavin Allwright such tweaks don't go far enough.

He says trade routes must change fundamentally in order to realize the wind's true potential On one of the most important routes of today's world trade - the way from Singapore through the Suez Canal to Rotterdam - the wind conditions are bad, for example.

"If you drove around the Cape of Good Hope instead, you could take a lot of wind energy with you," he says Estimates of the true potential of the technology vary depending on how realistic such adjustments are considered.

In 2017, environmental consultancy CE Delft estimated that 3,700 to 10,700 large ships could be equipped with wind propulsion by 2030 British market researchers hold 40 by mid-century.

000 ships imaginable – that would be almost every second merchant ship Gavin Allwright, on the other hand, believes that just about any ship could benefit from the drives -- at least if today's fleets were slowed down by about 20 percent.

Sebastian Ebbing, on the other hand, technical advisor at the Association of German Shipowners, is less optimistic He describes the technology as "extremely interesting" because every tonne of CO2 saved counts, but also says: "The systems are used where they can provide efficient support in constant wind conditions.

" In individual cases it is conceivable that a ship, thanks to the wind propulsion will take the route around Africa instead of through the Suez Canal "But I don't think the wind propulsion systems will significantly change the established shipping and trade routes.

How will shipping companies react to climate protection rules instead? "The solution that is likely to emerge for most ships is through a fuel switch," says Ebbing It is not possible to give a general answer as to which fuel could replace heavy oil, but the expert is betting on renewable, hydrogen-rich fuels such as ammonia, methanol or e-diesel.

Gavin Allwright argues that it would also be worth installing additional wind propulsion in ships that run on such fuels Because the alternative energy sources are expensive.

That will remain so for the foreseeable future Once you have invested in sails, the wind blows for free - but only where it wants to.

The one that is likely to arise for most ships is over fuel switching,” says Ebbing It is not possible to give a general answer as to which fuel could replace heavy oil, but the expert is betting on renewable, hydrogen-rich fuels such as ammonia, methanol or e-diesel.

Gavin Allwright argues that it would also be worth installing additional wind propulsion in ships that run on such fuels Because the alternative energy sources are expensive.

That will remain so for the foreseeable future Once you have invested in sails, the wind blows for free - but only where it wants to.

The one that is likely to arise for most ships is over fuel switching,” says Ebbing It is not possible to give a general answer as to which fuel could replace heavy oil, but the expert is betting on renewable, hydrogen-rich fuels such as ammonia, methanol or e-diesel.

Gavin Allwright argues that it would also be worth installing additional wind propulsion in ships that run on such fuels Because the alternative energy sources are expensive.

That will remain so for the foreseeable future Once you have invested in sails, the wind blows for free - but only where it wants to.

However, the expert is betting on renewable, hydrogen-rich fuels such as ammonia, methanol or e-diesel Gavin Allwright argues that it would also be worth installing additional wind propulsion in ships that run on such fuels.

Because the alternative energy sources are expensive That will remain so for the foreseeable future.

Once you have invested in sails, the wind blows for free - but only where it wants to However, the expert is betting on renewable, hydrogen-rich fuels such as ammonia, methanol or e-diesel.

Gavin Allwright argues that it would also be worth installing additional wind propulsion in ships that run on such fuels Because the alternative energy sources are expensive.

That will remain so for the foreseeable future Once you have invested in sails, the wind blows for free - but only where it wants to.

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