North Sails Mainsail

North Sails South Africa has completed the 1st stage of Moth sail development with America's Cup Sail Designer and Mothie Chris Williams. The goal of the project is to offer the fastest sail shapes in three different price levels and designs suitable for all sailors:

Step-up MonoFilm- 4mil/3mil combo All Purpose Design $915 USD

Dimension Polyant Aramid- ODL04 1mil Scrim Mainsail $1,198 USD

Cuben Fiber- CN13F.5 0.5mil AutoClaved Laminate $1,578 USD

The Cuben Fiber and Dimension Polyant mainsails offer approximately 1050g and 750g weight savings over the KA MSL-13 mainsails respectively.

***Prices are FOB Cape Town***

In addition to three construction styles, there are three designs to chose from:

All Purpose (AP) Mainsail- Designed for the club racer in a very forgiving shape with maximum power in lighter conditions with the ability to depower for high wind strengths

Light / Medium (LM) Mainsail- Designed for earlier foiling than the MSL-13 which can be translated to higher pointing ability in lighter winds and deeper angles downwind. Target windspeed 5-16kts.

Medium / Heavy (MH) Mainsail- Still powerful for maximum power off start lines, and good tacking / jybing performance, but more forgiving shape to allow control in strong conditions. Target windspeed 10+ knots.

Design Notes- The most obvious difference between the mainsails over the competitors sails is the profile:

While shifting the area higher up in the sail and reducing the foot length offers a slight advantage downwind and in lighter conditions, it is not the most important development. Using Norths advanced FEA/CFD suite of sail programs, the rig was carefully modeled in MemBrain to understand how the mast behaved in all conditions:

(Mast modeled in FEA with 30kg weight)

(Mast / Mainsail simulated in MemBrain)

Using these advanced tools has allowed the mainsail to be designed smoother and fairer than using traditional techniques of empirical development as well as learning how different controls affect shape and trim:

(Image showing effect of 1cm C-Ham on sail Shape)

In addition, forces from Flow (CFD) allow forces from many models to be compared to each other for easy validation of different sail designs.

(Prototype Mainsail onboard upwind aprox 12kts)

(Mainsail onboard downwind aprox 10kts)

Detailing

Weight has been a very important driving force in the development of the North Sails moth mainsail. Only the best materials have been selected. For example the square weave luff sleeve costs twice that of other materials, but is stronger and allows for less friction when adjusting the C-Ham (Esp if the sail is wet). Numbers and insignia will be offered as stenciled ink to save further weight.

Monofilm mainsail

(Prototype mainsail v2 on way to winning race 1 of the Heineken HPDO regatta by over 1 leg, windspeed aprox 5-7kts)

More photos from HPDO Regatta- Special thanks to PhotoBoat.com

PhotoBoat.com
PhotoBoat.com
PhotoBoat.com
PhotoBoat.com

Cuben Fiber prototype AP Design testing in South Africa

History- Originally North Sails was going to offer a 3DL mainsail for the Moth. However, due to technical issues with the 3DL Drum (3DR) we have decided that Cuben Fiber is a better solution for the time being. Below is an image of the 1st North 3DL Moth Mainsail.

Development- Our intention is to continually develop the mainsail design and construction, keeping a limited stock of sails. Therefore please feel free to contact me for further info or future developments and of course feedback is always appreciated.

Testing- While always ongoing, we are planning on some testing sessions in November 2008 to get feedback from the worlds top moth sailors- stay tuned for notes from these tests.

Ordering- Contact Chris Williams or your nearest North Loft to buy your own North Mainsail:

Chris Williams
chris(at)design.northsails.com
1-203-907-9323

http://www.northsails.com