Perched 40 metres above Barcelona’s bustling harbour, an iconic bronze statue of Christopher Columbus stands tall, its outstretched arm pointing towards the horizon. Erected in 1888 for the city’s World Fair, this monument commemorates the explorer’s historic voyage to the Americas in 1492. It also serves as a poignant reminder of the profound impact wind power has had on shaping our modern world. For over 5,000 years, sailing vessels dominated the oceans, until Austrian inventor Josef Ressel launched the first steam-powered boat in 1829, marking the beginning of the end of sail-powered commercial shipping.

Aeronautics meets shipbuilding 

Fast forward nearly two centuries after Ressel’s groundbreaking launch, and the sails are poised for a revival – thanks to three young inventors from Barcelona. Cristina Aleixendri, José Miguel Bermúdez, and David Ferrer, all natives of the city, drew inspiration from their hometown’s rich maritime history. But unlike their predecessors, who sought to expand the Spanish crown’s commercial reach, these three pioneers aimed to transform the shipping industry by making it more sustainable and cost-effective. This vision led to the founding of bound4blue in 2014. As co-founder and CTO David Ferrer recounts, “Our background in aeronautical engineering laid the groundwork for the technology we’ve developed. We noticed that soft sails were commonly used in sailing boats and yachts, but were surprisingly absent from commercial vessels. We saw an opportunity to apply our expertise in aerodynamics to design a high-lift device tailored to the needs of the shipping industry.”

Intelligent sails provide extra boost

The culmination of years of research and development came in 2021, when bound4blue’s rigid sail was put to the test. The eSAIL® is designed to complement a ship’s existing propeller, rather than replace it. By working together, the sail can help reduce energy consumption by up to 40%, depending on the wind conditions. To achieve this, the sail is equipped with a fan on the inside that directs air to optimise the thrust. This unique feature enables the eSAIL® to produce significantly more lift than a conventional sail - in fact, it can deliver the same propelling force using six to seven times less surface area.

According to David Ferrer, the benefits of the eSAIL® extend beyond fuel efficiency. “The sails are fully autonomous,” he explains. “They turn themselves to maximise the wind, regardless of its direction. This means they don’t require any additional crew members to operate them, making them a practical solution for ship owners and operators.” 

From startup to grown-up

On the November day when Julius Baer’s video team visited bound4blue’s headquarters, things were in motion in Barberà del Vallès, about a 30-minute drive from Barcelona. Some of the crew members were packing equipment as the company prepared to move to a larger location in Sant Cugat del Vallès, another town in Barcelona’s industrial area, where it is now fully established. The new facility has the capacity to host 120 people, a significant upgrade from their previous space. This expansion is a testament to the company’s rapid growth. “It’s almost scary seeing how things have evolved,” says Ferrer. “In just the last six months, we’ve gone from four ongoing projects to 18, with major players like Maersk, Eastern Pacific Shipping, and Amasus.” The order book now includes 43 eSAIL® for installation on 13 ships, a substantial increase from the 10 eSAIL® installed since 2021.

Using the tailwinds from regulations 

The strong growth is based on a favourable return on investment ratio for the shipping companies. Thanks to the low maintenance costs and a considerable reduction in fuel consumption, the eSAIL® are returning their initial investments in less than five years, while staying in operation for about 20 years. Even stronger tailwinds are blowing from the regulatory side. In recent years, a series of regulations, such as the FuelEU Maritime regulation and the EU Emissions Trading System, have been introduced in an effort to curb emissions in the sector. Maritime transport accounts for 3% of global CO₂ emissions, 15% of worldwide nitrogen oxides (NOx) emissions, and 13% of global sulfur dioxide (SO₂) emissions; it has a direct impact on our planet in the form of global warming and acid rain. The pressure is thus high on shipping companies to either switch to biofuels or reduce energy consumption in order to remain in business.

Shipping technology has ceased to be boring 

In this environment, the chances are good that wind propulsion will soon break out of its niche. “I expect that the technology will become a standard, alongside other innovative technologies,” says Ferrer. Besides the positive impact on his business, this technical revolution is something that makes the heart of any inventor beat faster: “For more than 100 years, vessels have been the same – a hull with a propeller and an engine. In the future, ships are going to look very different, with different fuels, different engines, wind propulsion, air lubrication, and many other technologies that we might not even know.”

If Christopher Columbus had lived today, he would most probably have welcomed these winds of change. Meanwhile, his bronze statue continues to look out over the harbour of Barcelona, spotting a growing number of eSAIL® on the horizon.