I own four Severne Convert sails and I was happy with them until I came back from a vacation at Maui. I rented Hot sails Firelight and didn't notice anything special about them. Was so windy that I did not have much mental capacity left for assessing the sail performance. However, when I came back to my own sails I noticed how they "screwed" themselves into the wind during the gusts. I had to push with the front arm to keep the angle of attack, or else, the sail would "over open" and almost knock me into the water while all speed was killed. I am guessing the pressure center moves backwards in the gusts.

I was told this happens with lightweight sails with fewer battens. My 6.7 has 5 battens.

I therefore borrowed two stiffer 6.5 m2 sails: Severne Gator (5 battens) and Severne NCX (7 battens). I have them rigged with the correct downhaul and the correct outhaul. They both show the same tendency of unstability in the gusts as described above.

Is this happening to you guys?
Why is it happening?
What is the phenomena called?
Are there sails that are more robust against this unstability?

(My skill level: water starts most of the time. Hooked in and planing, but having a hard time planing upwind. Gybes in less than 7 m/s. Tacks are very good. Footstraps sometimes, but not comfortably. Still on my Starboard Go 195, but I am also enjoying my Fanatic Gecko 133 in over 8 m/s)