Sail Model Guide

Overlay of the V6, V8 & V10 mainsail designs, note similar mold shape

In the latest Mothcast Bruce McLeod and Luka Damic raised the point that the new North Sails V-Series of models is a bit confusing (Thanks for pointing this out!). Obviously our intention was not to confuse the market, so I have tried to clarify things for potential customers. (By the way, if anyone ever has questions, please feel free to send me an email: chris at design dot northsails dot com.)

Concept- As stated before our concept and North Sail's philosophy is always to offer only the highest quality and fastest sails possible. After months of research and testing, we concluded that due to the range in rig stiffness and sailor sizes that a single sail design will never be able to compete against sails which are more optimized for a specific mast. Furthermore we we did not want to force our clients to buy a mast to match our sail design (Similar to what is done with windsurf sails).

Therefore we identified a range of luff curves for the various moth masts and then modified the sail designs to suite these masts. The V6 design therefore has 10mm more luff curve than the V8 and the V8 has 10mm more luff curve than the V10 design.

By tailoring a design to a specific range of mast stiffness we can then adjust the head width and sail shape. For example, a stiffer mast can support more girth in the top easier- which is easy to accomplish with the area saved by taking out a little luff curve.

See the image below to understand the effect of luff curve on the head width:

Similarly a sail design optimized for a softer mast needs to be slightly finer in the molded shape in the front to prevent the sail from being too draft forward in lighter conditions. This effect can be seen in the image below:

Further optimization- In a perfect world our lighter clients will sail with slightly softer masts than our heavier clients. Therefore lighter sailors would end up using the V6 design and heavier sailors using the V10 design. However, as one can see in the images, the sails are not radically different from each other. A rider who wants to have a more customized quiver of designs may end up with a V10 design for lighter conditions and a V8 sail or stronger winds. This would allow the V10 sail to setup with less downhaul in light winds for a given sail depth. We will continue testing these concepts as time goes by and can help our clients decide what is the best designs for their needs.

Over the next couple weeks we will be testing different mast/sail combos and we will give our suggested setup once we have more data.

Cloth Matters

X-ply monofilm (left) vs. ODL04 (right) used in the V-Series North Moth Sails

Instron Testing ODL04 at nearly 100kg

Instron Testing X-Ply (Fill test shown, warp, fill and bias are tested)

In sailmaking the shape and design of a sail are very closely related to the cloth used in a sail. Likewise the performance of a sail has a lot to do with the cloth it is made from, which is why we feel it is important to use cloth that costs 3 times more than film.

Below are the results from tests this week of standard X-ply monofilm vs. ODL04 Technora used in the V-series Moth Sails. It is not surprising to us that the ODL04 is 1.39 times more resistant to stretch in the warp at 1% strain even though it only weighs 56% the weight of monofilm. With sailcloth the old saying, you get what you pay for is very true.

ODL04 1mil film results.

Smaller Stretch numbers are better, larger Loat at 1% strain are better

X-Ply test graphs

Sail Sale

North Sails and Bladerider are offering a sail sale to introduce the North V8 Moth mainsail. Buy two mainsails with the carbon batten upgrade and receive 20% off retail (Team up with a buddy and save some cash)! Contact your nearest North Sails loft or click here.

The big question lately is, "What is the different about the North mainsail?" The original concept of the North Sail was to have a powerful design which made tacking, gybeing, starting, etc easier. However, over the last several iterations of the design, the shape has evolved to a sail which has greater top end speed potential through flatter sections and good takeoff power with an improved twist profile. As you can see in the image below, the sail is straighter in the back for low drag when foiling and has a tight mid leech for improved upwind pointing and early foiling.


North Sails philosophy has been simple for the past 50 years. Build the highest quality, best engineered and fastest sail shapes available- no shortcuts and no compromises. The V8 mainsail design is no exception to the North Sails philosophy with only the best material used on the body of the sail (1mil Dimension Polyant Technora Scrim), low friction Dimension Polyant Square Weave Dacron bias cut luff sleeve, RBS Epoxy or Tapered Carbon Fiber battens, shroud chafe protection, internal downhaul webs, adjustable head loop, tell tales, etc. The result is a very light, sail which is easy to use and has incredible top end speeds.

We also have a list of about 10 early test sails which are for sale for anyone who is interested. Mostly deeper sails which would be suitable for heavier sailors or lighter venues when just getting up is the key to winning and high top ends speeds are not necessary. E-mail me if interested- chris(at)design.northsails.com, or phone- 1-203-907-9323