[jbr]

I sail a 17 foot dinghy which has a vang and outhaul but no traveller or cunningham on the main. The jib is roller furling also without travellers. I sail on a lake which can be quite gusty and where the wind can really shift direction drastically. When the wind picks up above 10-12 kts I can and usually do put in a reef in the main and also partially furl the jib. In these conditions, I max out the main halyard, vang, and outhaul to flatten the main sail. I also feather to weather, ease the jib a little to widen the slot, and ease the mainsheet in gusts. Under these conditions, as you would expect, I''m sailing with the forward part of the main luffed to reduce heel. However, whenever I ease the main slightly, the entire main immediately luffs which causes me to lose power and forward momentum. The unopposed jib causes me to fall off further slowing me down, inceasing my heel, and requiring me to compsate with the rudder to control heel and maintain my heading. I''d appreaciate input from experienced sailors on two topics: 1) any suggestions for what I''m doing wrong and/or what else I should be doing (ie, is the trim on my main too critical because my slot is still too narrow)? 2) I''d appreciate input and clarification on the use of twist via vang sheeting to depower. What confuses me is that tightening the vang flattens and depowers the main although this by definition reduces twist and I had read that adding twist depowers the sail by spilling air from the leach. So by definition twist and flat sails are contradictory. A flat sail can''t spill air so it''s unforgiving to gusts and wind shifts; a sail with twist isn''t flat so it has more power! To make matters worse, if the flat main is unforgiving to gusts and windshifts and the main''s trim is overly critical as is mine I''m forced to ease more often than I should have to but am always damned when I do! The only thing I can think of is that maybe the use of twist depends on one''s heading (although I haven''t read that anywhere): a flat main without twist is what might be max depowered when close hauled and/or feathered and that a sail with twist (but flat otherwise) might be max depowered when reaching?

Thanks for any help and sorry for the lengthy question!