SAIL TECH

Sailmaking ain’t what it used to be, especially out in the Nevada desert

How North builds sails in the desert

Some years ago I visited the Bavaria factory and was amused at the thought of a powerhouse boatbuilder turning out its products smack bang in the middle of rural Germany, surrounded by fields of cows and crops. This past spring I visited two factory buildings in deepest Nevada that house the most sophisticated sailmaking operation I’ve ever seen.

Followers of high-level racing have no doubt noticed the increasing number of black and gray sails among the fleets over the last few years. These are 3Di sails, built at the North Sails factory—you could not call it a loft—in Minden, Nevada. What makes 3Di sails different is their construction—other sailmakers also use high-tech fibers oriented along the load paths in a sail, sandwiching them between layers of Mylar film. North’s patented 3Di process does away with the film, instead using a “spread filament” system of fibers laid up side by side into tapes, which are made into sail panels and then thermo-formed into a complete sail on a three-dimensional mold.

The result, according to Minden plant manager Gautier Sergent, is a sail that is light, extremely durable holds its shape for a long time, and is as close to a rigid airfoil as a soft sail can be. The world-girdling experiences of the Volvo 65 one-designs and the big French Ultime multihulls is a testament to 3Di’s longevity. With no film involved, the sails cannot delaminate and do not suffer from the mildew problems that can afflict film sails. Tears are easy to repair, and they take well to roller furling, unlike some film sails.

In short, the technology sounds ideal for cruisers, except for the expense involved in anything built with exotic fibers. However, the latest news from North is that the 3Di process is now being used to build Dacron sails. These 3Di Nordac sails, as they’re called, will be built in exactly the same way as the sails for grand prix boats, but use polyester fibers and resins instead of expensive carbon and aramid fibers.

I took a walk around the factory buildings with Gautier to check out the process. I have to say I was impressed. Here’s how the sails are built… s

1. It all starts here: spools of carbon, aramid and Dyneema fibers, each thinner than a human hair, feed a machine called the “pregger,” short for pre-impregnator. The fibers are grouped according to the kind of sail being built; raceboats will be mostly carbon, cruisers a mix of aramid and Dyneema.

2. The individual fibers are arranged side by side and “prepregged”—dipped in glue and laid onto paper backing. This is passed through a dryer to burn off solvents, and then cut into narrow tapes.

3. On the sailmaking floor, the tapes are loaded into a computercontrolled machine connected to an overhead gantry.

4. The machine lays out the tape according to the instructions the sail designers have programmed into the computer, building up the layers in high-load areas. There might be 60 or more layers in the corners and at reef points, and as few as six in the middle. Because of the size limitations of the sail-making floors, big-boat sails are built in sections with tapered “scarf” joints that will be overlapped in the mold. It was fascinating to watch this machine orient the tapes in what seemed like random directions but followed the load paths on the sails. It’s hard to credit, but between 11 and 12 miles of tape goes into a mainsail for a 65ft yacht.

5. Here is one of the smaller molds in action. The sail sections are carefully placed on the mold and covered with plastic sheeting. Pneumatically controlled jacks under the mold move individually to coax the designed shape into the sail. A vacuum sucks the air out from under the plastic and compresses the sail against the mold. The sail is then heated to set the adhesive and lock in the shape. Each sail is different (except for one-designs) so the mold must be re-adjusted between jobs.

6. Where flat sheets of fiber went into the mold, a shaped sail comes out, and is left to cure for five days.

7. It’s not all mechanized—human hands are needed for the final touches. The finishing floor was familiar territory at last.

8. And here’s the finished product, ready to be shipped to the customer.