Eco Boss Cap propeller hub now in production

Photo: EcoNavis

EcoNavis Solutions, a spin-off from the University of Strathclyde in Scotland has begun production of its patented Eco Boss Cap propeller hub, marking the transformation of a university-led research project into an industry-ready fuel efficiency retrofit technology.

The Eco Boss Cap is designed to eliminate the hub vortex cavitation that causes rudder erosion, vibration, and thrust loss in conventional propulsion systems.

Unlike finned boss caps, which only function optimally at narrow speed ranges, the Eco Boss Cap features a smooth, conical design with internal chambers and strategically bored holes. This configuration uses fluid pressure differences to improve flow uniformity, reducing torque while increasing thrust across a wide range of operating conditions.

The holes led to the solution being called the “holy boss cap” when it was first introduced.

The first unit, destined for installation on a general cargo vessel, has been cast at a foundry in China using designs optimized entirely through computational fluid dynamics (CFD). It is currently undergoing final machining ahead of a factory acceptance tests later this month (July).

EcoNavis worked with a U.K.-based propeller manufacturer to develop manufacturing drawings and specifications but will manage all client relationships directly.

The innovation began as a research project at the University of Strathclyde, led by naval architect Dr Batuhan Aktas.

“We started by identifying the failure points of existing designs,” he said. “Fin-type caps tend to generate drag outside their designed speed. We wanted to create something simpler and smarter; a passive system that could dynamically adapt without complexity or cost.”

Initial CFD simulations showed performance gains of over 3% in efficiency and reduction in propeller hub vortex cavitation. But early prototypes revealed a critical problem: some hole placements actually reduced propeller efficiency. The team returned to first principles, iterating the design using advanced parametric optimization tools.

The breakthrough came when engineers redesigned the internal chamber to align the suction flow with stagnation pressure points, allowing the cap to draw water through its core without impeding thrust.

These insights led to successful trials at a European cavitation tunnel facility, where the final design outperformed other energy-saving caps. Validation complete, EcoNavis fast-tracked the product to market.

Now under exclusive licence from the University of Strathclyde, the Eco Boss Cap is cast in a single piece, requires no moving parts, and can be installed in five to six hours during a normal drydocking.

“It costs about 50% less to manufacture than typical fin-based units and is expected to achieve a return on investment (ROI), in under six months for mid-sized vessels,” said Amitava Wye, EcoNavis’s chief operating officer. “What we’ve created isn’t just another retrofit solution with bold efficiency claims, but rather a scalable propeller technology proven to reduce fuel costs across a broad speed range. This is not a generic boss cap.”

Early trials showed a 3.1% improvement in propeller efficiency, a 1.1% increase in thrust, a 2% reduction in torque, and a 10% decrease in rudder cavitation. Noise was also reduced by up to 3dB, lowering the vessel’s underwater radiated noise footprint – a key issue for ESG compliance in sensitive marine environments.

The company recently closed a £550,000 funding round, secured a contract with a Thailand-based ship management company, and is preparing distribution partnerships in Greece and the U.S. The first Eco Boss Cap is in production, with follow-on orders under discussion.

“We’ve moved from lab to foundry in less than a year,” said Dr Aktas. “And with every unit, we’re refining not just our technology, but how fast and affordably we can deliver it.”o Boss Cap propeller hub enters production