https://www.youtube.com/watch?v=V-cHJJX1Dc0

https://www.youtube.com/watch?v=MAfKSVyklx0

https://www.youtube.com/watch?v=gYPlkgQ8jzM

https://www.youtube.com/watch?v=oPeldE2RExs

https://www.youtube.com/watch?v=zXSgZCDVWOM

https://www.youtube.com/watch?v=AY0ssDA70gY

https://www.youtube.com/watch?v=ZggxS6ZrVOw

https://www.youtube.com/watch?v=C6nD33j-OD8




Side-by-side masts 


https://www.yachtforums.com/threads/radical-new-sailboat-concept-twin-masted-swing-sail.12132/ 

 

Freewing  

 

 

Wing keel 

 

Bilge or twin keel