Turkish owner to pilot trial new propeller cap boss for retrofit market

An unnamed Turkish shipowner is to pilot trial a new UK-developed propeller cap boss that is aimed at the retrofit market for large deepsea vessels. The owner will retrofit one of its Kamsarmax bulk carriers with a propeller cap boss designed and manufactured by UK-based EcoMarine Innovations in the second half of 2024.

A second series of cavitation tests have confirmed EcoMarine Innovations’ Holy Boss Cap (HBC) propeller hub improves fuel efficiency by up to 5% at full-scale, as propeller manufacturers and shipowners vie for licensing agreements.

Full-scale CFD simulation of a ship operating at a design speed of 16.45 knots and turning a c.p. propeller with four different boss cap models, found the HBC the most efficient solution, outperforming existing hubs by a factor of 2.5 or more. Tests results mean that the simple to manufacture and install propeller hub can be retrofitted to large ocean-going vessels as a way of contributing to shipowners’ ESG (Environment, Social, Governance) goals to reduce carbon emissions.

Meanwhile, ship maintenance costs can also be reduced by using the HBC, as propeller hub vortex cavitation is the primary source of rudder cavitation and damages.

EcoMarine Innovations is a pioneering ship R&D group operating within Glasgow-based University of Strathclyde in Scotland.