Many boatowners, racers and cruisers alike, have upgraded their genoa cars so they can be adjusted while under load. These systems are great for achieving proper sail trim, but sometimes the genoa cars end up high enough above the deck that the sheet lead to the winch drum is on a downward slope. This creates an inherent tendency for the sheet to override itself on the winch.
To avoid this, a sheet must lead up, not down, to its winch drum. If the lead angle slopes downward, you should either lower the genoa car or raise the winch. One way to lower the sheet is to add a low deck-mounted turning block between the car and the winch, but this adds friction and complexity. Another way, although it’s not 100 percent foolproof, is to lead the sheet under a shockcord guide like the one shown in the photo. Putting a plastic roller cover over the shockcord helps reduce friction. This system works well when the sheet carries no load—during a tack, for example. But the shockcord will stretch under load and the sheet will tend to work back into an override position.
One good solution is to add winch pads to raise the winches. The stock teak pads sold in most chandleries and boating stores are only 1¼ inches thick; this may not raise the winch enough to eliminate the chance of an override. You can fabricate thicker teak pads, and most machine shops that work with Delrin or high-density polyethylene plastic can provide a base in any thickness you want.
A pad can be made lighter, if this is a concern, by drilling out the center portion, either partially (so it looks like an inverted bowl) or entirely (so it looks like a doughnut), complete with drain holes. Whatever the material or design, getting the jib lead to come onto the winch drum at the proper angle is a key element in eliminating the chance of a winch override. John Yeigh