@Knot Stressin'
@rgranger is correct about a downhaul. The picture is helpful to rig it.
I sailed all sorts of boats 10 to 25 foot with hank on sails. Hank on sails are what we had in my day. Not a one used a downhaul. We would go out on the fore deck and just pull the sail down and bag it. Quick, easy done.
Let me suggest that first you might want to rig your boat sitting in your yard or at the dock when there is no wind. Raise and lower the sails and learn what it takes to do this.
Go through all the steps over and over. You will quickly learn what is needed for your boat.
What
@Ken Cross stated is true. If your halyard is free to run, (no wraps or knots) then the sail may just fall under it’s own weight. On my boats it is what has happened. I have had sails get stuck, but it was because the sheet or the halyard for that sail jammed. The line twisted, someone tied a knot in the line, Soemone forgot to take it off the cleat...
When the sail starts down you can always reach up and grabs the cloth and give it some help.
More often when the sail stops coming down you really need to pull it back up and free what ever is the obstruction (there will be things that get caught). Once you pull it up the sail is released. You can then clear the obstruction then lower the sail. You have to try this a few times before you start to get the hang of it. That is why you go to the boat when there is no wind. Take a couple of beers.
Sit on the boat while on the trailer or at the dock and raise and lower the sails. If someone stops by and asks what you are doing, tell them. And offer them a beer. You might suddenly get a helper or a sailor that wants to help. Nothing gets much better than a free beer and playing with a sail boat.
Pretty soon you’ll be taking it out on the water and doing the same stuff, only you’ll likely have a new friend willing to help and sail with you.
All this fun and a can of beer.
This is such a great country