Hey Bing...
Depending on you rig (and I couldn't ascertain your boat model from my cursory reading of your post) and the angle to which your spreaders are swept back, a backstay may be superfluous (in the case of my rig) or completely unneccessary (as is, apparently, the case with your rig.) The cool thing about spreaders being angled significantly aft of the mast is that the shrouds supplant the backstay in terms of mast support from behind. Sometimes the uncool thing about this rig (aside from the inability to 'bend' the mast, as the 'sail shape' gurus like to do) is the limited extent to which you can ease the main, and the resultant 'chafe' of the main on the shrouds and spreaders while running, or on a broad reach, and that's where flying a chute becomes an excellent option. Eliminating the pole from the equation makes the cruising chute a great tool if you're short-handed, or (like me) just lazy. Anyway, if the boat was designed without a backstay, and the previous owner ran a full chute, using an asymmetrical with your rig would seem to be no problem at all. Of course, a call to your local rigger is always the best course of action, insofar as they are the true pros in this regard. But I'm pretty confident that running a slightly smaller sail with the tack attached to the stem of the boat would produce significantly less force at the top of the mast than a conventional spinnaker. And if your boat doesn't have a backstay, it doesn't need one. Good luck - Rick
