Windsurfing sails 2009: Cut out or normal clew?

by Maarten on January 24, 2009

Most sail brands on the windsurf market have released the racing sails for 2009. Some of these racing windsurf sails have cut outs some don’t. But what are these cut outs? Take a look at this picture and focus especially on the clew of this sail.

Neilpryde RS Slalom MKIII 2009

Neilpryde RS Slalom MKIII 2009

This Neilpryde RS Slalom MKIII has a short boom and the boom is not reaching the end of the sail. As if the sail has been “cut out” at the clew. Some sail brand created a nice marketing term for the cut out feature. For example, Neilpryde is calling it the “dynamic compact clew” concept.

Why this cut out?

Well, that is actually not totally clear. Some sail designers claim that it will boost the performance of the sail. Also it should be an advantage when you buy a new windsurf sail because you don’t need the ridiculous long booms anymore. Lets see what these top sail brands are doing with the new sails and if they are using cut outs and why they are using them.

Neilpryde RS Racing evo II

The RS Racing evo II is one of the sails on the windsurf market with the biggest cut outs. Off course Neilpryde is very convinced that this Dynamic Compact clew concept is a big improvement on the sails. This concept is actually not new. In the past there were several sail brand that had similar features, like A.R.T.. The main reason for using the cut out is creating a better twisting leech. The extended sail batten is now able to twist and without cut out it’s not. This way the sail automatically adjusts its shape and thus controls excessive power. Also the range and handling of the sails improve of this improved twisting, according to Neilpryde.

Neilpryde RS Racing evo II 2009

Neilpryde RS Racing evo II 2009

North Sails Warp F2009

The new Warp F2009 also has a small cut out. North Sails is calling the feature the “cut away clew”. The main focus is minimizing the rotation force and improve the handling of the sail. The is mostly due to the shorter boom that makes the boom stiffer. That stabilizes the profile in overpowered situation and reduces the sails centrifugal mass to greatly facilitate the handling.

North Sails Warp F2009 cut away clew

North Sails Warp F2009 cut away clew

Maui Sails TR-5

The Maui Sails racing sail has no radical changes. The sail is now in development for four seasons. Every season the new Maui Sails TR series is evolutionary. No cut outs at all. On the Maui Sails forum this feature has been discussed a lot. They have tested the cut out but didn’t find any performance improvements. Here is a quote from Barry Spanier (sail designer Maui Sails):

Look into nature. Is there any flying creature that has a big missing spot in the root chord of their wing? None that I am easily familiar with but of course if someone knows of something like this, we would like to hear.  If you were wanting washout, which is what they are talking about, I would think having tip washout makes more sense.

Maui Sails TR-5 2009

Maui Sails TR-5 2009

Severne code red 2009

The Code Red also has a small cut out but it is not very big. Also, they do not mention it as a key feature on the sail.

Severne Sails Code Red 2009

Severne Sails Code Red 2009

Gaastra Vapor 2009

The Gaastra Vapor has just like the Maui Sails TR-5 no revolutionary changes. No cut outs what so ever.

Gaastra Vapor 2009

Gaastra Vapor 2009

Simmer Style SC Race 2009

This Simmer Style sails  has an obvious cut out. That this sail is capable of reaching high speeds was shown by Ben van der Steen. He was windsurfing with this sail when he became IFCA Slalom world champion. More factors then a great sail played a roll during this championship. Ben has a lot of skill, he will probably go fast with almost any windsurfing sail. Simmer Style is saying the “clew cut out” improves the angle of attack aswell as allows for shape more forward providing faster accelration and better handling.

Simmer Style SC Race 2009

Simmer Style SC Race 2009


What can we concluded from these pictures? Some of these brands incorporate cut outs in their design development and some don’t. The brands that do, like North Sails, Neilpryde and Simmer Style talk about these  improvements:

  • Improved control (due to improved twist in the leech of the sail)
  • Better handling (due to the shorter boom length)
  • Improved angle of attack
  • Bigger range of use for the windsurfing sail

Other brands like Maui Sails and Gaastra don’t believe that cut outs are necessary to build high perfomance sails and have a more conservative take on sail design. The changes are more evolutionary rather than revolutionary.

Which sail will be the best sail? I don’t know! Sail producers have to innovate and incoprate changes if want to keep their sails on healthy level. They also need to stay ahead of the competition. Let the pro windsurfers start racing and we will see which sail will take the most wins.

What are your thoughts on cut outs? Is it an improvement? Let us know in the comments.


Rudie January 31, 2009 at 6:11 pm

Somebody once said to me: 'If your sail needs to lose power, you can put on a smaller sail otherwise just hang in there' 😛

gilligan February 22, 2009 at 7:41 am

They make sense. Besides whatever debatable aerodynamics stuff, you can have one boom for 4.7 to 7 plus sails. They keep the boom and sail in nice proportion. I have some 2003-2004 large freeride sails and they have annoyingly stuck out clews which calls for a long, heavy alum boom. Going to the other extreme seems pointless though, a nice notch to recess the butt end of the boom will do the trick.

Maarten February 24, 2009 at 2:43 am

@gilligan, well maybe you are correct. But with high performance sails it's not so important that you can only have one boom. Just like in formula one, only one thing counts. High speeds! But from a consumer point it's great to have one boom which you can use for a big range of sails.

Valkyr June 2, 2009 at 3:58 pm

Which is better now,Rs Racing or Warp ?

admin June 23, 2009 at 11:54 pm

I think that the Neilpryde RS Racing sails will out perform the North Sails Warp. Simple because all the speedsurfers and the racers I have met will choose those sails if they have the money and opportunity to sail those RS Racings.

But going fast depends on a lot of factors so don't rule out the other sails. I personally like the Maui Sails TR-5 Sails a lot.

GBR 139 August 13, 2009 at 12:47 pm

I have three RS Racing sails in varing sizes, due to the fact i race formula and have had many different sails. with and without the cutout clue design with the ealiest design being the nasih stealth in 2006. the many advantage of this new development in foil design is that it helps to reduce back hand pressure while sailing, this in turn anables you to trim the board better thus translating to a more even transfer of power to the fin resulting in better speed and more control. with the non-cut out design you tend to find in more demanding conditions that you end up muscling the fin and upsetting the board trim, this then makes it hard to fly of the fin and to maintain steady drive and even control.

hope this helps.

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