Four years ago Sabre Sails introduced a new product called Super K1. Super K1 used an off the shelf balanced sailcloth to demonstrate a revolutionary new manufacturing process. The response for this product was so overwhelming we decided to redesign the cloth for the loads on the F-31 Corsair trimarian and for a faster aerodynamic surface. Super K2 cloth had 16.5% more high modulus fibers in the primary axis and 73% more high modulus fibers in the secondary axis than the aramids laminates our competitors are using in their sails. Super K2 features a formed scrim, which is the basis for all premium laminates currently manufactured. It also features UV absorbers that significantly increase the durability of the aramid fiber.

The main reason behind the development of this product was to improve the aerodynamic surface of the sail and maximize the design shape, while reducing cloth waste and increasing manufacturing efficiency. Tri radials were the sails of choice in the 90s because the cloth manufactures could not make fill orientated cloth. Warp orientated cloth is required in tri radials construction. Not until special tooling was developed by Contender Sailcloth and Sabre Sails could a mill weave the fibers for a fill-orientated cloth.

There are several problems with a tri radial sail:

First and foremost, a tri radial sail has panel seams running perpendicular to the airflow. The seam disturbs the air molecules as it hits the seam. When the air molecules hit the seam they detach for the surface and travel some distance unattached from the surface (the sailcloth). When this happens, the sail looses lift and thus induces drag. Sabre Sails Super K2 and now Super K3 sails are not totally seamless, they do have seams running parallel to the airflow. A major "biggy" loft also realized this seam problem when they introduced their seamless sails.

Second, the more horizontal seams (broadseams), the better the sail design software transfer the design to the sailcloth. A tri radial can only have a maximum of 4 broadseams while this product has a broadseam every 54" up the luff. A typical F-31 Super K3 main will have 10 broadseams.

Third, since this cloth is continuous from the luff to the leech, this eliminates any speed bumps. Many sailmakers will use a different cloth type or weight on the luff panels than on the leech panels mainly to save cost. This creates what is normally called a transition "bump". Cloth will shrink at different rates depending on the weight and style of the cloth. This creates a transition "bump" which alters the design and shape of the sail and speed is lost.

Fourth, since this cloth is stronger in both its axis (warp and fill) than the cloth our competitors are using in their sails and was designed for the stress and strains of the F-31, the off axis or cloth misalignment is negligible. With a tri radial, cloth alignment is critical. This is one reason Sabre Sails has spent considerable time and money in doing stress and strain analysis on sail to evaluate the panel alignment. You can buy the best tri radial cloth in the world and if the sail designer misalign the cloth you will get distortions and cloth fatigue.

Fifth, A new dimension in sail construction was developed for the construction of these sails. A new glue was developed that is applied to the broadseams at over 400° F. This welds the seams together and has stopped seam creep. In addition the seams are sewn to assure longevity. We also developed a technique to remove the glued seam if the sail need to be repaired. In addition, stress relief tapes made of solid aramids fibers are installed at all the stress points and covered with a stress relief cover patch. These tapes and patches are designed to absorb the loads and provide longevity to the sail.

When it comes to comparing Super K2 and Super K3 cloths to carbon sail cloth The cloth wins hands down. Here are the hard true facts.

Carbon is on average 10% to 20% heavier than Super K3 for similar high load stretch numbers. Carbon has on average 3 to 4 times more stretch at low load (10#) compared to Super K3 due to crimp. Carbon has on average 15% to 20% more stretch at high load (200#) compared to Super K3. And Carbon is on the average 25% to 46% more expensive than comparable Super K3 styles.

The advantage of Sabre sails constructed from Super K3 can be summed up as follows:

• Cloth and manufacturing designed for the loads present in trimaran sails.
• Cross sectional panel layout for improved aerodynamics.
• More broadseams for smoother horizontal & vertical shape distribution.
• No transition bumps
• No distortions or cloth fatigue.
• New construction techniques has enhanced the longevity to the sail.

STYLE	WEIGHToz.	WARP 10#	200#	1%	Fill 1%
GPL 07	5.04	1.9	12.6	328	110
SK09	4.24	1.3*	12.5*	277*	114*
GPL 14	5.54	1.6	10.5	390	110
SK14	5.05	1.5*	10.1*	365*	112*

*SK09 and SK14 results show fill performance, the primary fabric direction for comparison to the warp (primary direction) of the other styles. SK warp numbers are compared to the fill numbers of the other styles. Weight is shown in oz. / sailmaker's yard. Lighter is better Warp 10# and 200# smaller number is better 1% and Fill 1% Larger number is better