Wouter,



As I have just finished the $ with Ullman, and the preliminary design needs,.....my weight,..the wind and waves in this area,...and I told Charlie that I DO NOT sail in class,...I gave him free hand to build me what I needed.



Which led to his formula for Uni-rig diamond tension.



As follows;

Light air - diamond never to go slack

Medium - diamond same as above

HEavy - almost, but not slack,..on the verge.



Tension



Light - set diamond wire to 'almost slack' tension.

Medium - 1 to 2 full rotation of turnbuckle from light position

Heavy - Maximum of 4 complete turns of the turnbuckle from light setting



Pre-bend



Heavy - 2 to 2 1/2 inch rake on spreader

Medium - 1 1/2 to 2 inch rake on spreader

Light - 1 inch or so rake on spreader

( ..this is my interpretation, Charlie O. said never more than 2 1/2,..less as it gets lighter.)



If you go the the North American A Cat site,..look for results,..you will see 5 or 6 out of 10 boats had Ullman sails ( all different platforms),...except for Skip Elliot, he had a Elliot-Pat sail, of course..!



The price was very good, by the way,...$1130.00 USD without battens ....20% less than the stock sail from Performance!



Bruce

St. Croix