Frandito - take a look at current top real yachts - they all seem have to have wrinkles in mains in light - some even refer to them as speed wrinkles - If the boat goes don't worry. My 12 has this as well but she goes mighty fine.
10 mins later - I have just been reading an old article about this wrinkle thing - quoted below [:)]
From the October, 1997 issue of Sailing World & Miami Valley MYC June 1998 Newsletter relating to the 10 Commandments of Boat Speed
"3 - Figure out what is maximum mast bend, and then strive to attain it in most conditions. Maximum bend is the point at which overbend wrinkles (speed wrinkles, inversion wrinkles, etc.) develop in the lower quarter to lower third of the mainsail"
So from this I assume that by taking some of the bend out of the mast the wrinkles should disappear. I'm going to try it this weekend and see if it works.
Chris
NZL1 Longtack
&
NZL110 Swept Away