Concentration of CO2 in the Atmosphere

Avast, Mate – Sail Ho!

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On August 1, the Pyxis Ocean set sail, under sail, on its maiden voyage from China to Brazil.

Martin Wahl

The 2017 Mitsubishi bulk cargo ship Pyxis Ocean, chartered by Cargill, was retrofitted by Norway’s Yara Marine with two of UK’s BAR Technologies WindWings. This work was done at the COSCO shipyard in China. The wing-like sails are estimated to save up to 30% of fuel usage and greenhouse gas (GHG) emissions, per their press release.

BAR Technologies incorporates aerodynamic expertise from Formula 1 race car designers and provides technology to America’s Cup hydrofoil yacht builders.

Each 123-foot-high rigid sail is made from steel and fiberglass consisting of three components: a central 32-foot-wide element and two 16-foot-wide wings on either side, each with a central pivot. This provides a total sail width of 65 feet and area of up to nearly 4,000 square feet.

The wing assemblies rotate to best position them according to the wind angle and speed. They fold down to the ship’s deck to allow access at port and for passing under bridges or through canals.

A “line-of-sight” camera replacement system allows an unobstructed view from the ship’s bridge as if the sails were not there.

As of this writing, the Pyxis Ocean is currently enroute from China to Brazil where it is planned to load a cargo of grain destined for Denmark. To see where it is now – go to Pyxis Ocean’s location on

Berge Bulk, a leading dry bulk shipping company, also plans to equip its Newcastlemax bulk freighter Berge Olympus with BAR’s WindWings by Yara Marine Technologies later this year.

According to Gavin Allwright, Secretary General of the International Windship Association, more than 30 ships are now equipped with wind-assisted propulsion systems, with a total of 50 to be reached during 2024, and the industry is on a trajectory to double every year.

What other wind technologies are in the offing?

Wind-assisted sailing technologies range from Michelin’s inflatable sails to rotor-sails that utilize the same spinning effect in airflow to achieve forward thrust that makes fastballs rise and curveballs bend. While rotor sails require engine propulsion to drive them, fuel savings between 6% and 8% have been confirmed.

Some of the other technologies include kites and aerodynamic hull designs that act as sails.

At this time, most are retrofit solutions allowing existing fossil-fuel powered ships to add sail propulsion. There are some initiatives to develop purpose-built sailing ships with supplemental engine power. For example, Veer Voyage and Windcoop are developing sailing ships that accommodate container shipping.

What if the wind dies down?

The trade winds have remained stable for eons. Additionally, the most common trade routes follow prevailing winds. All of the proposed new designs include auxiliary power, either fossil fuel or electric, for in-harbor maneuvering and when the wind is weak or not favorable. Advanced weather prediction and navigation support systems help determine optimal course planning during a voyage.

The industry is also investigating the feasibility of implementing other fuel sources for powering their fleets, including battery power, biofuels and synthetic fuels. Lloyd’s conducted a study surveying shipping companies for their assessment. The conclusion at this time is that a carbon fee is needed to make the conversions cost-effective.

Other issues?

Sail-assisted shipping is a new phenomenon and challenges range from vessel classification and obtaining insurance to crew training and general resistance to change.

In addition to height requirements for bridges and canals, there are other constraints for implementing sail-assist technologies – most concerning ship configuration for cargo storage and loading: the sail structures must not obstruct deck space required for crane access to cargo holds. Bulk carriers like the Pyxis Ocean and roll-on/roll-off (RORO) vehicle ferries are good retrofit candidates. Container freighters pose more daunting challenges as crane access and above-deck storage provide limited deck space for sail-supporting structures.

What’s the benefit?

For shipping operators, the biggest benefit is that the wind is free.

The sails cost a reported $2.55m, according to Yara Marine, and fuel savings should mean payback in as little as seven to 10 years – about a third of the lifespan of the typical cargo ship. Incorporated into newly built vessels with optimized hull and drive train design alongside advanced course planning, they could reduce fuel use by almost one third.

Additionally, consumer demand for low-GHG impact products is growing and some nations are considering imposing carbon emissions fees on shippers.

For the planet, the benefit is a reduction in emissions from an industry that, according to UNCTAD contributes about 2.8% of all GHG emissions and is a focus for GHG reduction mainly due to its rapid growth, its dependence on carbon-intensive fuels, and the sheer size of its business. More than 80% of the world merchandise trade by volume is transported by sea.

After a career in data product management, Martin Wahl has worked in biofuels since 2006, currently with Lee Enterprises Consulting, a large bio-economy consulting group. Dividing his time between California and New Hampshire, he serves on Corte Madera, California’s Climate Action Committee and is a Newfound Lake Region Association member.


The 2017 Mitsubishi bulk cargo ship Pyxis Ocean, chartered by Cargill, was retrofitted with two of UK’s BAR Technologies WindWings. The wing-like sails are estimated to save up to 30% of fuel usage and greenhouse gas (GHG) emissions. (Cargill)

Michlin Inflatable Sail (WISAMO)

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