Imagine a dragon like sail for water streams, it runs below the surface in the stream, and allows you to milk the potential energy of the water toward a directi

Imagine a dragon like sail for water streams, it runs below the surface in the stream, and allows you to milk the potential energy of the water toward a direction change for your boat.. https://en.wikipedia.org/wiki/Sailing_into_the_wind https://en.wikipedia.org/wiki/Sailing_into_the_wind But with the gulf stream and automated underwater dragging dragons