Years ago we had an interesting dilemma. While sailing from Long Island Sound to Block Island, the wind gradually picked up as the day progressed. Started out on a stbd tack close reach in 10 to 12 kts. The winds were well over 20kts when we arrived. As the wind had increased, I had tightened the main halyard to keep the luff tight. When we entered the Great Salt Pond at Block we were motoring through the inlet with the main still up. I went forward to drop the main only to find that the sail refused to come down. That left us in a crowded anchorage in a strong wind and we couldn't get rid of the sail. Dana has climbing steps on the mast, so Bonnie kept the boat in the channel while I ran up the mast to investigate the problem. At the masthead I found that the topmost sail slide was cocked off the sail track, not allowing the sail to slide. A screwdriver solved the immediate problem and the sail came down. Disaster averted!
Later, talking to a very knowledgeable sailmaker, The cause of the incident was explained: As the wind had increased on the crossing, I had retightened the halyard tension to keep the luff tight. The halyard was probably Sta-Set X. The line stretched tight to do its job. When we entered the harbor, the wind speed fell with being in the shadow of the land. When that happened the line relaxed allowing the top sail slide to move up higher then the end of the track. His suggestion was to replace the halyards, both main and jib, with a high modular type of line. This was all before Dynemma came on the market. The line we brought is called T900. Big bucks but we never had that problem again.
Jim