Engineering360: "Watch: Wing sail design unfurled for maritime use"

With only a 20% reduction in CO2 emissions, you won't see many of these on the high seas. If they could be used for 95% of the time, they might be used. Have a ship that uses a motor only for rough seas and docking. But the increased time and delay in cargo delivery will cause the system not to be used.

20% is a lot...