EcoNavis optimises wind-assisted propulsion with new Flettner rotor technology
Home › News › EcoNavis optimises wind-assisted propulsion with new Flettne…
EcoNavis Solutions is developing a next-generation wind-assisted propulsion system designed to enhance the performance and commercial viability of Flettner-type rotor sails for deep-sea shipping.
The company’s Eco Rotor Sail introduces a patented tail-appendage device designed to increase thrust, reduce power demand, and widen the range of wind angles in which rotor sails can operate efficiently.
Flettner rotors — rotating cylindrical sails first introduced in the 1920s — are enjoying a comeback as shipowners seek credible ways to cut fuel consumption and greenhouse gas emissions. But a major deterrent to much wider take-up is performance reliability when the wind direction changes. Anton Flettner’s underlying principle has changed little in more than a century.
Expanding the wind window
The EcoNavis design essentially broadens the rotor’s effective “wind window” by reshaping the wind flow in the rotor’s wake to deliver higher thrust with lower torque demand. According to the Glasgow-based innovator, initial simulations indicate an increase in thrust of up to ten per cent alongside a five per cent reduction in torque.
The Eco Rotor Sail retains the conventional rotating cylinder but introduces a fixed aerodynamic appendage downstream to stabilise the airflow behind the rotor, reducing losses and allowing the system to continue generating thrust as wind conditions change.
“Flettner rotors already offer one of the highest lift-to-drag ratios among wind-assisted devices, with a relatively modest footprint, but the main drawback has been the narrow band of wind angles — typically beam and stern-quarter winds,” said EcoNavis CEO and founder Dr Batuhan Aktas. “The Eco Rotor Sail expands the range of wind angles over which the rotor can operate efficiently.”
Aktas said compared to existing rotors, the new design strengthens the case for the technology on larger commercial tonnage. “It offers more energy savings and lower operating costs,” he said.
“By recovering energy that would otherwise be lost and optimising the flow behind the rotor, we can provide a Flettner rotor design with a greater operational range. This means shipowners can have greater flexibility in route planning and more consistent performance over a typical trading year, without fundamental changes to vessel operations.
“If you can maintain performance across a wider range of conditions, you change how the technology is used. It becomes something operators can plan around, rather than something that depends on favourable weather,” Aktas said.
Validation and next steps
Eco Rotor Sail development is backed by a £100,000 research grant from Scottish Enterprise to take the £265,000 project through to validation and demonstration stages. The next phase will move into physical testing.
EcoNavis plans to build a scale model for wind tunnel trials at Politecnico di Milano, Italy, to validate performance and correlate results with simulation data. Subject to successful validation, a full-scale prototype could be built for shipboard trials as part of an integrated power system.
Contact EcoNavis
Contact EcoNavis to discuss hydrodynamic and aerodynamic optimisation for ship efficiency.
Related News
EcoNavis launches Eco Boss Cap Savings Estimator for shipowners
Home › News › EcoNavis launches Eco Boss Cap Savings Estimator for shipown…
EcoNavis has launched a new online savings calculator to help shipowners and operators make an initial assessment of the fuel-saving potential of an Eco Boss Cap retrofit.
Available on the EcoNavis website, the Eco Boss Cap Savings Estimator allows users to enter basic vessel information — ship type, dimensions, engine power and fuel price — to generate an indicative estimate of annual fuel and cost savings from the novel propeller hub. The tool is intended as a first-stage screening assessment before a full vessel-specific optimisation study.
Dr Batuhan Aktas, Founder and CEO of EcoNavis Solutions, said the calculator has been developed to help owners understand how relatively small propulsion efficiency improvements can translate into meaningful commercial benefits.
“Shipowners are facing a combination of fuel price volatility and rising regulatory pressure,” he said. “When bunker prices rise and carbon costs are added, even modest efficiency gains can have a meaningful commercial impact. The purpose of this calculator is to give owners and operators a practical first indication of where an Eco Boss Cap retrofit may justify a closer vessel-specific study.”
Indicative savings across vessel types
The Eco Boss Cap Savings Estimator draws on indicative modelling across a range of common vessel archetypes, including bulk carriers, tankers and container ships. Across these vessel types, indicative efficiency improvements are in the range of 2.7% to nearly 4%, depending on vessel size, propulsion characteristics and stern configuration.
For example:
- A 35,000 dwt handysize bulk carrier operating a 6,000 kW main engine for around 250 days per year could reduce annual fuel consumption by about 138 tonnes, equivalent to approximately US$142,968 per year at a VLSFO price of US$1,036/mt.
- A Panamax bulk carrier could reduce fuel consumption by about 266 tonnes per year, equivalent to US$275,576 per year on the same basis.
- For an 8,000 TEU container ship, annual fuel savings could exceed 1,100 tonnes, or US$1,139,600 per year.
(The VLSFO price used for these illustrations is the Ship & Bunker Global 20 Ports Average for 18 March 2026.)
Vessel-specific optimisation
Dr Aktas said the projections reflect EcoNavis’ design philosophy of vessel-specific hydrodynamic optimisation rather than generic appendage designs.
“Many retrofit devices are based on standard geometries that are applied across multiple ships,” he said. “Our approach is different. We analyse the flow conditions around each vessel’s stern using computational fluid dynamics and develop the boss cap specifically for that hull, propeller and rudder arrangement.”
Eco Boss Cap is a CFD-optimised propeller boss cap developed to reduce hub vortex formation and associated losses, improving propulsive efficiency and helping operators reduce fuel consumption and emissions. It is bespoke to the vessel and can typically be installed within a routine drydock work scope. Typical lead time from project start to delivery is around three to six months.
EcoNavis has already completed its first commercial installation on the 177 m general cargo vessel SFYC Araya, operated by Thailand-based Kaizen Ship Management. Early voyage monitoring from an initial installation indicates promising performance over 3% as reported by the fleet performance team.
Try the Savings Estimator
Related News
EcoNavis and Franman partner to bring Eco Boss Cap technology to Greek shipping market
Home › News › EcoNavis and Franman partner to bring Eco Boss Cap technolog…
EcoNavis Solutions has signed an agency agreement with Greece-based company Franman to distribute its Eco Boss Cap technology in Greece, Cyprus and to Greek interests worldwide. The agreement opens one of the world’s largest commercial shipping fleets to the energy-saving device.
The deal was signed after discussions at the Hellenic Institute of Marine Technology, where EcoNavis presented research on the Eco Boss Cap’s performance gains and emissions reductions.
Retrofitted to a vessel’s propeller hub, the Eco Boss Cap improves propulsion efficiency by reducing hub vortex cavitation and optimising water flow. By delivering measurable reductions in fuel consumption and CO₂ emissions of between 3% and 5%, the technology supports the global shipping industry’s transition towards more sustainable operations.
Dr Batuhan Aktas, Managing Director of EcoNavis Solutions, said: “From our first discussions, it was clear that Franman shares our commitment to environmental sustainability. With its network and deep understanding of the Greek maritime sector, the company is the ideal partner to introduce the Eco Boss Cap to the region’s shipowners. Together, we can help shipowners take meaningful steps toward meeting global environmental standards.”
Founded in 1991, Franman has established itself as one of Greece’s leading agents of shipbuilding equipment, parts and services, representing more than 200 international manufacturers. As a one-stop-shop partner, the company has equipped over 5,500 ships and today connects more than 700 shipping companies with trusted suppliers and solutions worldwide.
Franman CEO Costis Frangoulis said: “Since our formation, we have supplied our clients with equipment that is proven to deliver results. The Eco Boss Cap offers a straightforward and effective way for shipowners to improve fuel efficiency, cut emissions and save on operational costs. Our partnership with EcoNavis is an opportunity to contribute to a more efficient and sustainable shipping industry while reinforcing Franman’s role as a trusted bridge between innovation and the Greek fleet.”
The agreement also allows for potential expansion into other European markets through Franman’s wider client base.
Explore vessel-specific performance improvement
Related News
EcoNavis and ShipDyn cooperate on novel fuel-reducing Y-Hull® form
Home › News › EcoNavis and ShipDyn cooperate on novel fuel-reducing Y-Hull…
EcoNavis Solutions has joined forces with ShipDyn Ltd. to optimise and commercialise an innovative hull form Y-Hull® that combines the stability and deck space of a catamaran with the efficiency and single-shaft simplicity of a monohull.
The Y-Hull®’s distinctive geometry features twin forward demi-hulls before merging into a single monohull aft. From the bow, the vessel looks like a regular catamaran, with twin demi-hulls reducing resistance and wake impact. But midway along the parallel mid-body, the demi-hulls merge into a single monohull, allowing the vessel to operate with one engine and one propeller while retaining the broader beam, stability and deck area typically associated with a twin-hull.
The partners say the patented Y-Hull® form delivers not only improved stability, lower wake impact and enhanced passenger comfort, but also a substantial reduction in fuel consumption.
From safety concern to commercial innovation
After witnessing a Bangladeshi passenger vessel capsize in the wake of a large commercial ship, ShipDyn founder, and EcoNavis COO Amitavo Wye designed and built a 13 m steel Y-Hull® prototype craft with the aim of improving stability and reducing river bank and coastal erosion.
“The idea came from a real-life safety concern,” said Wye. “But what we have found is that the Y-Hull® delivers much more: fuel savings, more environmental benefits and more comfortable seakeeping. This makes it relevant for operators facing today’s performance and sustainability challenges.”
The passenger ferry Wye built is now operational, ferrying passengers across a Bangladeshi waterway. The ferry owner has also reported a 25% reduction in fuel consumption compared with a monohull vessel of the same dimensions.
Next steps
Dr Batuhan Aktas, Founder and CEO of EcoNavis Solutions, said: “When I first saw the Y-Hull®, I recognised its potential for applications like crew transfer vessels, which are critical to offshore wind but consume significant amounts of fuel. By optimising the design, we can create vessels that are more efficient, more comfortable, and more in line with a ship operator’s sustainability and net-zero goals.”
EcoNavis and ShipDyn are now taking the design further by refining the hull form through computational fluid dynamics, simulation and towing tank tests. The intention is to validate performance, optimise hull geometry and produce technical and commercialisation plans.
In addition to the renewable energy segment, the partners see opportunities for the novel hull in the leisure marine, passenger and commercial shipping sectors, especially in environmentally sensitive or confined waterways where reduced wake can mitigate against shoreline erosion. Larger merchant ships such as tankers and bulk carriers could see substantial fuel and emissions reductions at scale, with project analysis suggesting around 4,500 tonnes of CO₂ saved annually for a 240 m tanker.
Explore innovative vessel design
Related News
EcoNavis accelerates growth with Innovate UK ICURe Grant
Home › News › EcoNavis accelerates growth with UK innovation funding and G..
EcoNavis Solutions, the maritime technology company behind the novel Eco Boss Cap propeller hub, has secured a major investment package and joined a leading accelerator programme as it scales operations to meet growing industry demand for its hydrodynamic efficiency solutions.
The Glasgow-based start-up has been awarded £300,000 in funding through the UK’s Innovate UK ICURe Exploit programme to support the commercialisation of university research. EcoNavis Solutions is a commercial spinout from the University of Strathclyde.
The funding follows EcoNavis Solutions’ successful completion of all stages of the ICURe process, including extensive product testing and validation.
“This is a unique form of funding,” said EcoNavis founder and CEO Dr Batuhan Aktas, “because it reimburses 100% of the costs as we scale, including salaries, exhibitions, customer engagement and business development. It’s a significant endorsement of the commercial potential of our technology.”
Glasgow growth
EcoNavis has also been accepted into the Smart Things Accelerator Centre, a specialist technology scale-up hub in Glasgow. The 18-month programme provides mentoring and support across four structured growth stages. The company now occupies dedicated office space at the centre and has grown its core team, including a Chief Technical Officer, Chief Operating Officer, lead CFD engineer, and an administrative manager.
“The growth in 2025 has been substantial,” said Aktas. “At the start of the year, we were just a couple of people. Now, with funding and structured support in place, we’re putting the right expertise and infrastructure in place to take environmentally and energy-efficient solutions through to large-scale commercial adoption.”
EcoNavis is also awaiting responses to several additional grant applications. These include a £100,000 request to Scottish Enterprise under the Smart Grant scheme and a US$500,000 proposal to the US-based National Fish and Wildlife Foundation to support collaborative trials on offshore crew transfer vessels in the Gulf of Mexico.
The Eco Boss Cap, a hydrodynamic energy-saving device fitted to a ship’s propeller hub cap, is the first of the company’s research-led projects to be brought to market. Under development since 2022, the Eco Boss Cap is designed to improve propulsion efficiency by more than 2%, reduce emissions, and deliver measurable fuel savings across a range of vessel types and speeds.
Explore vessel-specific performance improvement
EcoNavis develops hydrodynamic energy-saving devices tailored to each vessel’s hull, propeller and rudder interaction. To assess whether Eco Boss Cap or an integrated optimisation package may be suitable for your fleet, contact the EcoNavis team.
Related News