Carbon foil: Criteria to consider before buying

When you want to choose a new foil, you are attracted to 100% carbon foils because all the brands suggest that it is the best of the best. However, the reality is not so clear-cut. What are the criteria to consider before buying a carbon foil?

In this article, we’re going to talk about what we don’t tell you about carbon foils to help you make the right choice.

“If a carbon foil is sold for twice as much as an aluminium foil without having a gain in performance, there is no point” Bruno Sroka.

The carbon foil must bring more performance, more rigidity, more glide, more finesse of flight, less drag, more nervousness otherwise you might as well keep an aluminum foil.

What is a carbon foil?

It is common to hear that people think that a 100% carbon foil is always more efficient, stiffer or faster than a foil with an aluminum base (mast & fuselage), but THIS IS NOT TRUE. To be efficient, a mast must be thin and extremely rigid, which is contradictory; The more you refine a mast, the more susceptible it will be to bending and twisting. It is easy to make a carbon mast as rigid as an aluminium mast if it is thick, but with a production cost often 2 times higher, you pay twice as much for a mast for the same performance, which is useless.

The challenge of developing a high-performance mast is to use the best carbon with the best draping plane in order to have a mast that is both thin and ultra-rigid. Indeed, a steep mast is the most important thing to have a high-performance foil. The stiffness of a mast makes it possible to stiffen the entire foil (the mast is like a connecting arm between the board and the load-bearing part of the foil), the stiffer it is, the more responsive the foil is and therefore the downforce and the reaction of the foil will be precise. So stiffness is fundamental. For more information on the differences between 100% carbon foils and aluminum foils, check out our article on the subject. In short, having a high-performance carbon foil requires a thin and thick and rigid rope mast.

1. The Quality of Carbon Fibers

The quality of the carbon fibers used for the mast is essential. There are three main types of carbon: basic, mid-range and high-modulus (high-modulus). The latter results in increased stiffness, reduced elongation and superior responsiveness, making it a preferred choice for high-performance foils. However, high modulus masts can cost up to two to three times more than basic carbon masts. For example, in our carbon foil, we use M40J which is a high modulus carbon used for Formula 1 and aerospace. It provides flexural stiffness with little elongation but costs much more.

2. Mast Profile

The thickness and chord of the mast are of immense importance in the rigidity and drag of a mast. A thin mast (about 14 mm) will have much less streak than a thick mast ( > at 16 mm). It will glide better and allow you to reach higher speeds with its ultra thin profile while giving you a better response thanks to its stiffness. The Sroka carbon mast is available in 14mm and 16mm thickness depending on your preferences and needs. The Elite mast in 14 mm will be very thin and stiff. The 16mm mast will be less slippery but lighter and a little less rigid but cheaper.

How do you make a rigid carbon mast? Our Pick:

The construction of a carbon mast is a very technical process. But here’s how to get a rigid carbon mast.

To have a steep mast, there are only two solutions :

Either you increase its thickness and its rope to stiffen the whole thing and consequently you can foam the inside and be light.
This is the simplest and least expensive solution, but we greatly increase the drag of the mast and therefore the mast is slower.

Either we increase the quality of the carbon fibers that we put in the mast (high modulus fiber) and we increase the quantity of material so that we can reduce the thickness of the mast and the rope as much as possible. So we have a reduction in drag, an improvement in glide, speed, while having a very responsive and efficient foil.

At Sroka, we have therefore chosen the second option. Offering you one of the best carbon masts on the market, combining thin thickness, thin rope and foolproof rigidity.

The fuselage

There are two ways to make a fuselage:

Or we keep an aluminum fuselage which will be heavier and which will force you to disassemble your foil after each session in order to avoid oxidation between the aluminum and the stainless steel (the screws).
Either the fuselage is made of carbon in order to avoid this oxidation and to save weight. But it will be more vulnerable to impacts. So we’ll have to be more careful. The last option is to make a titanium/carbon fuselage.

We at Sroka have chosen the carbon fiber option for a 100% carbon foil and to reduce the price of the foil, we also offer an aluminum fuselage.

The length of the fuselage determines the maneuverability of the foil, the longer a fuselage is, the more stable it is in the longitudinal axis but the less manoeuvrable the foil. Conversely, a very short fuselage will increase maneuverability and the ability to pump easily, losing longitudinal stability.

However, if the mast is thin with little rope, its manoeuvrability is increased, making it more manoeuvrable. Thus, one can maintain a longer fuselage while being just as maneuverable as with a less maneuverable mast that requires a shorter fuselage.

We refer you to the video next to it which explains all the differences.

The front wing

The performance of a foiling front wing depends on various characteristics, such as its wingspan, chord, thickness, twist and the profile used. This is defined by the ratio aspect, which is the ratio between the wingspan of the wing and its chord. For example, the higher the ratio, the larger the wing relative to its chord. It is therefore more elongated and narrower.

Low aspect ratio: These are foils with a lot of rope and very little wingspan. They will be great to start with, however, they will quickly saturate in speed due to their large string.
Medium aspect ratio: The perfect compromise between high aspect and low aspect. These foils are accessible to all levels. They are perfect for beginners while giving you a lot of room for improvement. They correspond to the foils of our Classic range. In large size or from the Control range in the performance range.
High Aspect Ratio: With a high aspect ratio, these foils are more technical than the others. Allowing a maximum of glide of flight and therefore an excellent glide and will be able to fly for a long time. They match our High Aspect foil range.

The Stabilizer

The role of the stabilizer (stab) or rear fin is to stabilize the foil.

The bigger the stabilizer, the more stable the foil will be, but it also means that there will be more drag and therefore you will go slower. On the other hand, a smaller stabilizer will stabilize the whole thing less but will offer much more glide, because less drag and can also allow you to go faster.

At Sroka we offer 3 types of stabilizers,

The 300cm2, the most stable stabilizer in our range, perfect for beginner riders or riders with big front wings.
The 240 cm2, the medium, a compromise between stability and speed. Adaptable with all our front wings. It will be your best friend in light wind and also for people looking for comfort and speed in navigation.
The 180 cm2, a speed weapon. With its ultra-slim profile, it will allow you to exceed your speed limits.

It is important to remember that the use of adjustment wedges will allow you to adapt it even better to your sailing style and your size. It also allows us to reduce the number of stabs and thus meet all needs. By increasing the lift, by putting an angle under the rear screw or by removing the angle (i.e. by increasing the thickness under the front screw), the lift and therefore the drag are reduced. For more information on adjusting stabilizers with corner shims, watch this video.

To conclude:

To have the best carbon mast, you need the best carbon and the best draping plane with a thin profile with little thickness and rope. Compare, take a look, you will see many differences. If the information is not clear in a brand. Ask yourself why? Or ask them!
A mast with a thinner profile and a thin rope like the Sroka carbon mast will allow you to reach higher speeds and offer a better response from your foil.
The way the mast is made is very important. An ultra-light carbon mast is absolutely not a sign of quality. It will be supple and will surely lather on the inside. As a result, it will be less rigid and more “marshmallow” underfoot.
The choice of the front fin is essential in order to adapt your equipment to your requirements and thus optimize.