For years sailmaking has followed the same general principals. Sails were made out of pieces of fabric stitched together into a sail that were strong enough to take the loads they would be used in. Over the years the materials have changed in the effort to make sails lighter and give them better shape holding ability; from canvas to Dacron to mylar laminates with a long list of yarn types; and the panel layouts changed from vertical to cross cut to radial, but the process was still the basically the same.

 

In recent years that has begun to change as sailmakers have looked for methods to make stronger and lighter sails. Current thinking is rather than build a sail with individual panels build a light weight mylar membrane and then support that with fibers that run across it in various directions to take the different loads that are present n the sail.

 

There are currently 3 types of membrane sails that are readily available. The first, and the highest end, are the pure “string sails” such as the Dimension D4. This type of sail is made full size by laying out a bottom layer of mylar, laying yarns on top of that layer that follow the paths the designer has chosen, and then laminating it all together with another layer of mylar on top. Depending on the use for a particular sail the mylar layers may also have another layer of yarn scrim already laminated to them. Shaping is induced with cross cut seams, which produce the smoothest shape. These sails are the strongest for their weight available, but are expensive, especially for boats under 45’ to 50’. Because manufacturing cost are high due to the cost of the equipment and size of the laminating area, smaller sails cost more per square foot to produce. For this reason we have been involved with the development of the other two types of membrane sails that are much better suited for smaller sails.

 

The second type utilizes yarns laid out on individual 60” wide panels. These are made in similar fashion to the D4 type except instead of stringing the yarns out on a full size membrane these sails use the computer controlled yarn laying head to map out where the yarns are on each individual panel of a cross cut sail. The panels are produced by laying yarns down on the bottom panel of mylar, a second layer is put on top, and the panel is run through a commercial laminator. The panels are then bonded together using the the new ultra-sonic Ultra Bond system.

 

The third type, Load Path,  starts out with cross cut panels using one of the newer laminates that have been designed just for cross cut sails. The sail is assembled using a laminate that is lighter than is needed for a pure cross cut sail, and then the load path yarns are laminated on top of it to provide the strength needed in different areas of the sail. The advantages of this type of sail are that it is lighter than a cross cut sail, has continuous yarns running from corner to corner and corner to edge to fully support the membrane and take care of all seam loading, and is much more cost effective than either a tri-radial or pure string sail. They are slightly heavier than the pure string sails because of the extra layer of mylar that the load path yarns are laminated with, but are coming in about the same weight as a tri-radial sail. These membranes are now being produced for us by Bainbridge Sailcloth with production facilities in Florida.

 

We believe that over the next few years tri-radial sails will mostly disappear, being replaced by some type of load path sail. Cross cut sails produce beautifully shaped, smooth sails and are much more efficient to build. In a typical tri-radial sail 25% to 30% of the cloth is waste because there is so much area lost in cutting out all the small, differently shaped triangular panels from a roll of fabric; in a cross cut sail a little bit is lost because we have to leave enough space between the panels and the edges for cutting, but they have about 95% efficiency. There is also a huge difference in the time it takes to assemble a tri-radial that will have between 35 and 50 individual panels, and a similar size cross cut that will have only 10 to 15 panels. On a load path sail for a 30’ to 40’ boat we are seeing prices that are 5% to 15% below that of a tri-radial sail.

 

We design these sails the same attention to detail as we would any other sail we build. The cut file is then emailed to the membrane production facility in Florida where they warehouse the various base fabrics. The panels are cut on a computer driven cutter, assembled into the full size membrane, and then have the load path yarns laminated on top. We specify the yarn density and the type of yarns we want for the particular application; generally a blend of carbon and aramid but there is the option for all aramid (although the price difference is so small we don’s generally see much reason to go that way), or Pentex in the case where class rules dictate it. Where durability is more important they can also be made using a film that has a taffeta already laminated to one side. This adds about 1.5 oz. per yd. to the final weight, but does make the finished sail more abrasion resistant and longer lived. The finished membrane is shipped to us for final assembly. We do the second layout where it is measured and trimmed to exact size for rule compliance, corner reinforcement and things like reefs, batten pockets, draft stripes, numbers, insignia, windows, and chafe patches are installed. The luff tape and tablings are sewn on and the sail goes to handwork to be finished with necessary hardware.

 

If you are racing at the true Grand Prix level we will certainly continue to recommend the D4 membranes. But for most racing boats under 50’ we believe our new Load Path sails truly offer a great product at a great price. We have built them for everything from Capri 25’s to a Beneteau 57, including a complete inventory for the new Antrim 40 “XL”. Call us know for current pricing and delivery times!