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A second series of cavitation tests has confirmed that the Eco Boss Cap propeller hub improves fuel efficiency by up to 5% at full scale, as shipowners and propeller manufacturers express interest in the technology.
Full-scale CFD simulation of a ship operating at a design speed of 16.46 knots and turning a controllable pitch propeller with four different boss cap models found the Eco Boss Cap to be the more efficient solution, outperforming existing hubs by a factor of 2.5 or more.
According to the trials report, researchers concluded that propeller hub vortex cavitation was significantly eliminated by the holes in the Eco Boss Cap models, with vortex cavitation disappearing after interaction with the holes.
The test results mean that the simple-to-manufacture and install propeller hub can be retrofitted to large ocean-going ships as a way of contributing to shipowner ESG goals to reduce carbon emissions.
Eco Boss Cap inventor Dr Batuhan Aktas, a Chancellor’s Fellow in the Naval Architecture, Ocean and Marine Engineering Department at the University of Strathclyde, said: “Our approach to improving propeller efficiency is unique in both design and application. It diverges from traditional methods that typically use propeller hub fins to achieve similar outcomes. We are receiving a tremendous amount of industry interest.”
A key differentiating aspect of the Eco Boss Cap is the emphasis on cost-effectiveness and ease of manufacturing. Unlike conventional propeller boss cap fins (PBCF) which are complex and expensive to produce, the Eco Boss Cap offers a simpler and more economical solution without compromising on efficiency or performance.
Ship maintenance costs can also be reduced as propeller hub vortex cavitation is the primary source of rudder cavitation and damage. In addition, the Eco Boss Cap reduces underwater radiated noise and vibration levels, which impacts the migratory, mating and feeding habits of marine mammals.
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.