This video shows how the sailwing is being controlled by the flap just like an airplane wing.

A powerful fan is blowing air onto the sailwing. When the autopilot sends a wireless command to the actuator that moves the flap, the sailwing starts moving until the flap points in the same direction as the wind is blowing. This way, a relatively small force is required to move the massive sailwing. As Archimedes said: “Give me a lever and a place to stand and I will move the Earth.” Practically, only a 10-degree sailwing adjustment is needed to provide the maximum lift, but as you can see, even 45 degrees is possible. To me, it looks like magic.

Who invented it?

This invention dates back to World War II (Fin Utne's boat Flaunder destroyed by the war) and was used on some manned yachts in 1990's (Walker Wingsail). Today you don't see yachts like this, because traditional sails seem to be more economical. However, an autonomous boat with a wing/tail system came to light in 2004 (the Atlantis project, University of California, Santa Cruz). It's kind of resurrecting a decades-old technology. Now I'm relying on it to cross the Atlantic.

(Source: Catalyst, N16, 2004, Catalyst, N17, 2004, A.Y.R.S. No. 14, 1957)