A Sail Replacement Strategy
A Sail Replacement Strategy
How do you know when a sail is past it's prime? The camera never lies. "Sail Tech" from our November/December 2009 issue.
One element of laminate sails technology is the “shrinkage” problem, where the wrinkling of an otherwise smooth surface causes a reduction in the sail’s dimensions.
“A typical 40-foot light No. 1 genoa could shrink as much as 6 inches on the luff over the first two years,” says Baxter. “This is a problem of any film-type sail regardless as to what construction method is used. Typically, the lighter the sail the more likely it is to suffer from this shrinkage as the sail ages. In most cases some simple retuning will do a lot to keep the sails fast for longer.”
Given this, how does one decide to replace or try a re-cut?
It depends on the severity of deformation, but sometimes recuts can add a little more life to the sail. Keyworth says the typical re-cut is done by adding luff-curve and sometimes negatives
to the leech to help flatten the exit shape.
“At best, and only if the sail material is sound and not too damaged from sunlight, you can get a maximum of two re-cuts to a sail,” says Keyworth. “After that, you’re just wasting our time and your money.”
But while this shape may be OK for one more season, perhaps with a minor re-cut, there must be a point at which a sail has outlived its useful life and simply has to go. So, when should we replace?
“This is all determined on what is most important,” says Baxter. “In most cases, a boat will try and stay with some sort of normal sail rotation. For boats that have larger inventories, there are some sails that do not get much use, and others that do most of the work. Even though mainsails are up all the time, the abuse they get is usually far less than that of a genoa or spinnaker. This is a result of the sail being supported on two of its three sides, not hitting the mast, and not being flogged as much due to its having battens.”
The most commonly replaced sails, therefore, are the No. 1 genoa, half-ounce spinnaker, and then the mainsail. In most sailing venues, No. 3 jibs are not used as much, so they tend to retain their design shape longer. Baxter and Keyworth both say careful planning is a must, so when it does come time to replace the No. 3, an owner can slot it in.
And what about spinnakers? They’re harder to evaluate in shape, but much of the same principles apply, but perhaps even more so: due to their constant handling through sets, jibes, and drops, the melamine finish on the cloth, which is important for both strength and to limit porosity, starts to break down.
“In many cases spinnakers are probably the most overlooked sails in the inventory,” says Baxter, “and it is common to see boats out sailing with five-year-old spinnakers. The sails still look fine shape-wise, but they are porous. Because they are unsupported in how they fly, they load very differently than a mainsail or genoa. As the finish wears off, more air passes through the sail than is retained.”