It's a dilemna
Hello, Swept spreaders make for tighter sheeting angles, in addition to giving the shrouds an aft component. On your boat, as you note, that component is not sufficient for significant air; thus the presence of the backstay. But if you tighten the backstay, it is difficult to avoid slacking the uppers, as the masthead moves aft. Fractional-rig people have been dealing with this one for a long time, and it can be dealt with, but will require some tuning finesse. Start with a copy of Selden's tuning guide, which goes into the problem in some detail. Then experiment with just how much effect your uppers can have on jib sag, documenting amount of sag vs windspeed vs shroud tension. I've found that you want to be pretty tight here. Next you can play with how much you can tighten that backstay without utterly slacking the uppers. You will know that you have when the mast begins to lose lateral stability near the top. You will likely have to put up with a bit of this, but with sufficient tension on uppers and intermediates, the wire will compress as it is unloaded, and will still mostly keep the mast in place. You'll probably find that you will have less range of motion available to you on the backstay, but a net gain in performance, if only because of that tighter sheeting angle. Fair leads, Brion Toss
