Greetings all, This is my first post. Long time lurker, first time poster. I am looking at building a new mainsail for my M-15. I have a kit from Sailrite that was originally made for an O'Day 20 that I will adjust to fit the M-15. According to my calculations and from input from the good folks at Sailrite, this adjustment should be quite simple - simply reduce the luff to the appropriate length and shorten the foot slightly. The only difference so far is the weight of the cloth which is 4.9 oz compared with the typical 3.8 oz. I have been told that this should make no appreciable difference in sail shape and performance but should positively affect sail life. My main question, (no pun intended) is whether to build the sail with or without a roach and battens. My read of Don Casey's "This Old Boat," and Emiliano Marino's "The Sailmakers Apprentice" leads me toward no battens. I do not, however, want to sacrifice performance too much. The boat is new to me, so am looking for input from others who know the sailing characteristics of the M-15. My intended use is day sailing on Lake Michigan out of Milwaukee, with 1 or 2 week-long cruises each season. Any input is appreciated. John Hippe Hull # 405 - currently nameless