[notable_user]

Sails are crazy efficient, and are most effective when wind is blowing across the bloat. So if you point a fan across the boat you’ll get a forward force vector and sideways force vector.

Edit: Based on the summary of the episode provided it looks like mythbuster didn’t exploit this property of modern sails.

[Tempest1981]

And this (Magnus effect), which still amazes me: https://en.wikipedia.org/wiki/Rotor_ship