Hey. I thought of publishing some textures for sails.
You simple apply these to spheres and rescale the spheres to the size you like.
The higher the X scale is the more wind it have caught. =)
Here's the textures and two screenshots.
You can also turn on wind and experiment with that.
Remember to turn on "show backfaces"!
https://gyazo.com/14516e3669e92e8f12ee19520d6826d2
https://gyazo.com/bb22e9ac007c1365c872b83fb7c61968