The wind-assisted propulsion technology to be tested on a kamsarmax bulker by charterer Cargill has won Approval in Principle (AiP) from classification society DNV.

The AiP assures the practicality and safety of the WindWings rigid sails developed by UK-based BAR Technologies (BARTech) and paves the way for the first retrofit installation next year.

Two wings will be installed on the kamsarmax, expected for delivery to Cargill in 2022, with one of them funded by the European Union as part of Project CHEK to assess the energy-saving potential of multiple technologies working together.

DNV assessed the WindWings system's design specifications, safety and usability, plus general applicability to seagoing vessels. The AiP also examined their deployment and functionality in operation, use in extreme weather and system redundancy.

Simulation-driven marine engineering consultancy BARTech partnered Norwegian scrubber maker Yara Marine Technologies this year to handle the global manufacture, sale and delivery of WindWings. Yara is building a portfolio of emission-reduction technologies.

The solid wing sails are expected to offer up to a 30% average fuel reduction for bulk carriers, tankers and other large vessels on global routes by combining wind propulsion with route optimisation.

Further to the AiP, the emissions reduction potential of WindWings has been independently analysed by maritime consultancy the Wolfson Unit.

Martyn Prince, principal research engineer at the Wolfson Unit, said: "We were engaged by a client to take a closer look at WindWings, and are pleased to report that our predictions of the solution's performance were in good agreement to those of BAR Technologies."

DNV Maritime senior vice president Per Marius Berrefjord said class approval can build confidence for ship operators by demonstrating that new technologies that help to lower fuel carbon emissions have been rigorously assessed to long-standing, high-quality technical standards.

"We look forward to seeing the system in operation when it hits the water,” he added.

BARTech chief executive John Cooper said the validation was "crucial to proving the technical and commercial viability of emerging energy-efficient technologies to shipowners and investors alike".