Problem:
The opening in my Gloucester 20's mast slot is about 24" above the boom. If I put a stop above the opening, the bulk of my sail hangs unceremoniously off the mast, two feet above the boom. The only way around that is to guide each slug past the opening any time I raise or lower the sail.

Solution:
I found a 36" piece of 3/4" aluminum tube at Lowe's. I squoze it down to an oval shape to fit inside the mast slot, cut a slot to match the one in the mast, and inserted a sail stop to raise and lower it. To operate the gate, I reach under the boom and loosen the stop, then pull the tube down below the mast opening. After I feed all the slugs into the slot, I raise the tube back up, closing the gate, and the slugs are held captive for the entire height of the mast.

This is a 6" piece of tube that I used to test the concept.	Shaping the full size part, with dowels inserted to help keep  it reasonably uniform.	Sawing a 24" long slot in the 30" long formed tube. (The most tedious task ever undertaken by man.)
Sail stop inserted through the back.	The lower end of the finished part.	The sail-stop/gate-control under the boom.
Open	Halfway	Closed
Slugs go in.	Gate is closed.	Now I can haul away without having to tend the sail slugs.