Hi Doug, A sail stop is the word requested, but as others have mentioned the little devils have a nasty habit. They loosen themselves ever so slightly and then when you are not looking they jump out of the sail track, hit the cabin top, jump to the deck and then into the drink. As they disappear from view into the water, you will hear a faint derisive laugh, as the sail stop goes, gurgle, gurgle. The solution to this problem is to defeat the bastards. Jerry says: use duct tape Giles says: drill a hole through the sail track and insert a cotter pin My solution is to take a piece of bungee cord and tie it around the mast (two turns). It holds the sail slides in place: can be moved down to release the sail slides; and doesn't jump overboard at the first opportunity and then give me the Bronx Cheer. Costs almost nothing. Is replaceable when needed. Doesn't get lost. ...and is a nonmechanical solution to the problem. Connie M15 #400 LEPPO