Make sure you have installed the perimeter wire rope, added wire rope clamps, and attached turnbuckles to every corner.
With the turnbuckles fully extended and greased, attach the first corner by connecting the D-shackle to the connection point and the eye of the turnbuckle. It’s best to start at a corner with a higher attachment point.
Attach the remaining corners in the same way as the first. If the sail has more than 3 sides it is best to attach opposite corners first rather than move around the perimeter. The final corner may require a come along, winch or tensioning device. While attaching the corners of the sail, the wire rope should be sliding with the stretching fabric. Make sure that your wire rope clamps are loose enough that this can happen. Also, make sure that the wire rope remains on top of the D-rings.
Once you have connected the sail at every corner you should remove slack from the wire rope if there is any. Push the loose ends further into the pocket as slack is pulled out of the corner loop. With slack removed from the wire rope, tighten down the nuts on the wire rope clamps with a ratchet or socket wrench.
Once the clamps are tight, tighten down the turnbuckles until your sail has achieved the tightness you desire. This is accomplished by turning the body of the turnbuckle with a wrench, or other tool, so that the ends of the turnbuckle are being drawn together with each turn. Go slowly to avoid binding or seizing. Make sure you are tightening the buckle and not loosening it. Spinning the turnbuckle body off the threads could result in having to detach corners and repeat previous steps.
Finish each corner by tightening down the lock nuts against the body of the turnbuckle.
Special Note: While the instructions above apply to most installs, there are limited exceptions that occur with small (under 9 foot sides) and large sails (over 25 feet). With smaller sails you may need to tighten the turnbuckles a few turns before tightening down the wire rope clamps. With a larger sail, you may need to tighten down the clamps before the last corner is attached. On larger sails the “take” on the turnbuckle may not be large enough to fully stretch out the wire rope if the clamps are tightened after all the corners have been attached. In the case of these exceptions, experimentation may be needed to get the desired tensioning.