Last week I visited North Sails in Nevada to gain better understanding of the all new way to build sails – 3Di. I met Dan and Jeff Neri, originally from the east coast. Dan is the production manager and Jeff are working with 3Di.
Below are some pictures from the production of the well known 3DL range, and in the next article we’ll cover what’s new.
North makes 3DL in Minden, Nevada, and in Sri Lanka. In Minden, they’re 140 employees and produces 5.000 3DL and 3Di sails every year. They run three shifts seven days a week on the molds, and two shiftson the floor completion the sails. It’s all about efficient manufactoring, and very few of the employees sails.
In Sri Lanka they’re 800 employees and produces approximately 2500 3DL sails (in slightly smaller sizes) per year but also lots of One-Design and downwind sails. On any given day they can have 350 sails in different parts of the production.
It seems odd that North choose to manufacture sails in the middle of Nevada, but it’s close toCalifornia, and it is terrific conditions for skiing and other outdoor activities. And it is rumored that one of the determining factors was that this is one of the world’s best places for gliding.
During the past 15 years, 3DL dominated the America’s Cup, Volvo Ocean Race, TP52, Farr 40 and many other classes. It was in 1990 that North first built a sail, a genoa to a J/24, with fibers between two films laminated on a mold. Although materials and processes have developed, the principles are still the same.
The sail is built between two layers of mylar film. Mylar comes in large rolls and is available in slightly different weights. They can also color it (Puma wants to have red sails), although it is quite complicated.
One of the critical factors is the glue necessary to hold together the two films and fibers in between. There are adhesives that withstand UV, and there are adhesives that withstand moisture. But unfortunately there is none that can withstand both UV and moisture.
The glue is applied to the film…
which is then allowed to dry before being cut for each sail.
In order to shape the sails there are a number of molds that can assume the shape the sail designer want. Here we see the biggest mold, just the right size to handle a mainsail for the proposed America’s Cup 90-footer.
Or maybe the design was restricted by the sice of the mold? Check the width of the sail head. 8 meters?
Here’s an overview of the different molds. Often the bigger molds are used for downwind sails, where it is challenging to get enough form. Upwind sails is one thing, but we see more and more downwind sail on boats (VO70, Open 60 or Maxis) that is built in 3DL.
They create the right form with the help of hydraulic cylinders that adjust after the sail shape. The aft edge has long stroke but quite far between adjustment points (not much shape in the sail) …
but at the front has short stroke cylinders that are close together (more shape).
Here’s the configuration file, which translate the shape of the sail to settings for the hydraulic cylinders. In this case, about 200 cylinders. From the sail design software, they also get layouts for the mylar films and fibers.
Technora and Aramid have to dry completely for 72 hours before use. If there are too much moisture, it evaporates in the lamination process and creates bubbles in the sail. Carbon fiber does not dry as it is water repellent.
The red fibers are dyed especially for Puma downwind sails.
Mylar films are assembled into a reasonably good sail shape, which can be pulled out to be completely smooth. The lower film also serves as one part of vaccum bag.
Here Rodney Schilling lay out the carbon fiber. The machine puts carbon fibers based on the design and Rodney make sure they stick are stays in place.
In order to stick they pass quickly through glue. One option would be to impregnate the fibers, but when they would become stiff with dried glue. Now, the individual strands move inside the yarn itself.
A jib to a Cookson 50.
Lots of fibers at the tack. It has been discussed if it’s possible to make a sail with “no glue”, but you wonder how it would be possible to attach two mylar films with this much fiber in between?
Here you can see that the vacuum hoses in place.
When all fibers are in place, vaccum is applied and the sail is laminated. In this case by experienced Cory Daggett. Not so easy as the carbon fiber conducts heat very well and easily gets too hot.
Alternative ways to apply pressure would be to “roll” the sail with a small weight machine, but it seems difficult to come down between the fibers. You could also bake the sail in an autoclave, but it did not sound as if it could be done in a cost-effective way.
Here’s a jib to a Grand Soleil 46.
After lamination as the sails of they cure for five days before they are ready for a thorough quality control. The little black sail is a TP52 main! Below that a sail to a Swan 90 and at the bottom a super yacht code 0.
The top shelf is filled is rejected sails. The most common problem is material that doesn’t meet specifications and render problems in the process.
In order to streamline the process, kits are delivered to each sail with the correct rings, webbing, numbers, batten pockets and everything else.
Here’s a mainsail in 3Di to an Hong Kong X-41. Note the sewing machine running on rails, and move along the sail. It is a must for the really big sail that you can not pull back and forth.
The sewing machines are places in small wells and rotate, which makes it much easier to sew webbing and reinforcements. And they are also movable between a number of different positions on the floor. Smart.