I will make some assumptions first. I assume you cut three separate pieces that will fit perfectly around the shaft? Each piece had the ends cut on a bias? The joints should also be staggered at 12:00, 4:00 and 8:00. Put the first piece on and slip it into the cupped nut. Use the cut PVC pipe placed on the shaft up against the stuffing and using a large channel lock plier grab the back of the nut and the face edge of the PVC facing the stern and squeeze the pliers to push the PVC against the stuffing. Do this all around the circumference. Then do the same for the second piece. At this point you may want to screw the nut up a little tight to squeeze the stuffing a bit more. Release the nut and install the last piece. Then reengage nut and snug up and do not over tighten. After the boat is back in the water tighten the nut more to just stop any drips over 20 seconds. After using the boat for a short run keep checking the drip and make adjustments accordingly. After a few hours of use adjustment won't be needed.