EcoNavis Solutions has begun production of its patented Eco Boss Cap propeller hub, turning a university-led research project into an industry-ready fuel efficiency retrofit technology. The first unit, for installation on a general cargo vessel, has been cast at a foundry in China using designs optimised through computational fluid dynamics (CFD).
It then underwent final machining followed by factory acceptance tests in July. EcoNavis worked with a UK-based propeller manufacturer to develop manufacturing drawings and specifications, but will manage all client relationships directly.
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No hub vortex cavitation
The Eco Boss Cap eliminates 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.
Research project
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 says. ‘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.’
Parametric optimisation
Initial CFD simulations showed performance gains of over three per cent 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 optimisation 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.
Also read: Tiny propeller defects can increase underwater noise
No moving parts, installed in five to six hours
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 fifty per cent 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,’ explains Amitava Wye, EcoNavis’ 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.’
Efficiency gains and reduced radiated noise
Early trials showed a 3.1 per cent improvement in propeller efficiency, a 1.1 per cent increase in thrust, a two per cent reduction in torque, and a ten per cent decrease in rudder cavitation.
Noise was also reduced by up to 3 dB, lowering the vessel’s underwater radiated noise footprint – a key issue for ESG compliance in sensitive marine environments.
Follow-on orders under discussion
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 US. 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,’ states Aktas. ‘And with every unit, we’re refining not just our technology, but how fast and affordably we can deliver it.’
Picture: The first Eco Boss Cap is destined for retrofit installation to a general cargo vessel (photo by EcoNavis Solutions).
