The sails will be made of steel and composite materials

Friday, November 6th, 2020

The Oceanbird transatlantic car carrier being designed by Swedish shipbuilder Wallenius Marine will be the world’s largest wind-powered vessel:

With capacity for 7,000 vehicles, the 650 foot-long vessel is a similar size to conventional car carriers, but it will look radically different. The ship’s hull is topped by five telescopic “wing sails,” each 260 feet tall. Capable of rotating 360 degrees without touching each other, the sails can be retracted to 195 feet in order to clear bridges or withstand rough weather.

The sails, which will be made of steel and composite materials, need to be this size to generate enough propulsive power for the 35,000-ton ship.

Although “the general principles of solid wing sails is not new,” designing the Oceanbird’s sails has been a challenge, says Mikael Razola, a naval architect and research project manager for Oceanbird at Wallenius Marine.

That’s because these are the tallest ship sails that have ever been constructed. “This ship, at the top of the mast, will be more than 100 meters (328 feet) above the water surface,” says Razola. “When you move up into the sky that much, wind direction and velocity change quite a lot.”

To better understand the atmospheric conditions at this height, Wallenius mounted sensors on top of its existing vessels, while they were crossing the Atlantic, and gathered data on wind velocity and veer (a clockwise change in wind direction), up to 650 feet above sea level. “All of this information has helped us design an efficient wing and hull system, that can make the most of the power available in the wind,” says Razola.

Oceanbird Car-Carrier

It won’t be completely emission-free, however, because it will still rely on engines for manoeuvring in and out of ports and for emergencies.

With a projected top speed of about 10 knots, Oceanbird will be slower than standard car carriers, which can travel at 17 knots. It will take around 12 days, instead of the standard seven, to cross the Atlantic.


  1. Gavin Longmuir says:

    “It won’t be completely emission-free, however, because it will still rely on engines for manoeuvring in and out of ports and for emergencies.”

    Of course it won’t be emissions-free. Vast quantities of fossil fuels will be required for mining the iron ore and smelting the steel for the vessel’s hull. Even more for making its steel & composite sails.

    While I have not seen figures for ships, about half the total lifetime energy use of the cars this ship will carry happens during the original manufacturing — and much of that has to be fossil fuel.

    As usual with the Renewable Energy Scam, notice that capital costs of the drive system are greatly increased. The shipowner has to buy a conventional diesel engine as well as those expensive sails — and will have to run diesel generators to provide the electric or hydraulic power needed to rotate & control those sails. When the cost of capital returns to normal levels (Euro negative interest rates are unsustainable), this kind of ship will only be able to sail slowly to the breakers yard.

  2. Bruce Purcell says:

    “The sails…will be made of steel and composite materials,” so you can’t furl them in dirty weather. Death ship in the North Atlantic.

  3. Albion says:

    Pie in the sky, or rather, pie in the water.

    If sails are so good (and they are) then build sailing ships again. Conventional design ships.

    Trouble is, you need experienced sailors to handle them and we worked to get rid of them a while ago.

  4. Allen says:

    I guess if they wanted to make it emission free they could turn it into a galley. Slaves might be a bit of an issue though.

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