"Cloth" that's edible (or even better, yummy)?
You can press cotton candy into a thin sheet that resembles paper or cloth. Put the candy between two pieces of parchment, flatten it with your hands and cut into shape. Consider that the sail may be delicate or very delicate, depending on how thick you make it. To attach it to the mast use caramel, isomalt, couverture, marzipan ...

El Bulli used to serve 'Flower Paper' made with this technique. Watch https://www.youtube.com/watch?v=oLpTCN9pT2Q to see a Demonstration (Flower Paper starts around 6 min 30 sec).