在许多方面，这是一个明显的解决方案。在过去的几个世纪里，海上的世界贸易仅由风力推动。现在，我们正在为了现代生活标准，寻求替代燃烧化石燃料的交通工具，一些些人正在转回到可再生能源解决方案，如在我们的油轮，散装货船和集装箱船上使用风能。全球化与经济增长意味着将昔日的木帆船直接恢复是没有意义的，但有几个21世纪的想法可以使风力航运再次变为平常。
Ship design certainly has a way to go to return to its heritage and take advantage of the wind's free, renewable resource in the same way we have reinvented the windmill to produce electricity. However, it's worth remembering wind turbines took a long time to evolve into the structures optimised and deployed at scale we have today. In fact, they're still developing. Scientists and engineers have debated for years about the relative merits of two, three or more blades, of horizontal versus vertical configurations, and of onshore versus offshore generation.
For ships, the design process for wind technologies is potentially even more complicated and multi-dimensional. There are soft sails, rigid "wing" sails, flettner rotors (a spinning cylindrical vertical column that creates lift using the Magnus effect, originally conceived by Flettner in the 1920s) and kites all vying for a share of this market. Soft sails are fabric sails, most reminiscent of existing sailing ship designs, examples include the Dynarig and Fastrig. Rigid wing sails replace the fabric with a rigid lifting surface like a vertically mounted aircraft wing - for example the oceanfoil design.
A flettner rotor is a vertical cylinder rotated by a motor. The rotation modifies the air flowing around the cylinder to generate lift much like the lift generated by an aircraft wing (it's referred to as the Magnus effect). While there are many examples of all four, so far it's the kites and the flettners that have seen the most significant implementation on large merchant ship designs.
