A vise or vise grips are good options I think, but the little remaining gap is likely not a concern. Anyway, after completing the sail I realized I should have used soft shackles instead of hanks. Oh well!
Nice work! I am intrigued that you feel the need for a riding sail. I am guessing, based on some of my own experience, that the length of the boat combined with her freeboard and structure make her finicky at anchor/mooring. I know how frustrating that can be when a boat starts sailing back and forth on her bridle. I am looking forward to a followup as I didn’t get the chance to try a riding sail on our last boat.
I suspect for most sailboats the greatest amount of windage is forward of the beam. The wind will try to blow the bow off, but it comes up short because it's tethered to an anchor or mooring ball. I'm hoping the riding sail will shift the balance of windage astern so the effect of the wind is mitigated. We'll see! :)
Please report out how this worked. Try with and without to see how effective it is at different wind speeds. I think it came out very nice. Looks like a professional.
I'm glad you asked... A riding sail is used in attempt to make the boat more comfortable while at anchor. If needed, the sail is deployed at the stern of the boat and helps keep the bow pointed into the wind. The intent is to minimize a boat's yawing from side to side, which might become uncomfortable when the beam of the boat becomes more perpendicular to waves.
So thankful for that earlier question, as I didn’t know what a riding sail was either. And, I must admit, most people I know can’t even turn on a sewing machine-let alone sew their own sail. Good show, Owen!