This workbench photo shows the long aluminum sheet, with 12 numbered 'chutes," the numbered plastic dishes, and the products shown behind each. In the unnumbered center chute, not used in the test (it's an overlap portion), is a dish containing the various lead weights used to pull the dishes to the edge.

The goal is a mainsail that hoists easily and drops like a rock. A main that doesn't strike when set loose can be a menace if the weather is pushing you or maneuvering room is limited.

Most important is a good mast track, clean and smooth, with no resident spider webs or wasp cells. Silky spider cocoons cause great problems. They collect lubricant, dirt, and oxidized aluminum. Sailmakers hate such debris; they call it "mast mud." It's the black stuff you find on your mainsail's luff.…