Some dates and some pictures will help us to understand better the evolution history of the landyacht:
2000 years before C. the Egyptian pharaohnes used the landyacht to move around the desert
500 years before C. Chinese builted some bamboo landyachts used to transport people.
In England, from the beginning of the 19Th century, the gig horses were replaced by the kite which allowed the gig to move thank to the wind action.
As you can see there have been different trials to use the wind as motive power before to arrive to the actual landyacht.