This is not a complicated matter.... just like with anything else on these boat, KEEP IT SIMPLE STUPID.... I try to live by it on the water...less chance of a robust simple setup breaking. Set your mast, rudders...etc for the most/best power. THEN deal with your other problems (helm, rotation, etc) w/o messing with you sail tune. Don't use your diamonds to help rotate your mast... Mark has it right.



The position of spreader and tension not only set the initial state of the mast, but also dictate how the mast will react under load (sheeting/dh..etc) So, by screwing with your sweep, you may not change how much INITIAL prebend you have, but you WILL change the bend characteristics of the mast. It may then depower too quickly or not quickly enough or just not bend properly to suit the sail (inversion/poor shape).



Another interisting point... on a Nacra 6.0 or other boomless rigs, battens make a HUGE difference in how your mast rotates...



like Mark said, on a boomed boat, move the bail aft. Personally I think there is a problem in your rotation system if the mast is not rotating properly. I hate those auto bunge systems. They don't rotate far enough and move too much...



Unless you have a "personal" sail maker (Randy/Saber/other) cut your sails for YOU, you have to be careful with the numbers you might get. I got a brand new set of sails for my 6.0 ~2-3 yrs back (sold it)... called EP sails and they gave me mast/batten settings...well... they were WAY off. For doing the initial setting, measureing your sail and mast is best, but once you start to know your rig, you can adjust based on feel.



I don't remember who said it, but one of the masters said, "I just try to get my boat in the ballpark....the rest is sailing..."



my 2 c's



Will_R