{"id":101129,"date":"2025-04-14T07:55:50","date_gmt":"2025-04-14T07:55:50","guid":{"rendered":"https:\/\/srokacompany.com\/2022\/05\/how-to-surf-foil\/"},"modified":"2024-10-30T15:22:45","modified_gmt":"2024-10-30T15:22:45","slug":"how-to-surf-foil","status":"publish","type":"post","link":"https:\/\/staging.srokafinal.lets-preprod.com\/en\/blog\/how-to-surf-foil\/","title":{"rendered":"How to Surf Foil"},"content":{"rendered":"

Louis-Arnaud surf-foil in Mauritius, equipped with the Fast Flyer 4’6 board and the High Aspect 1190 Lift S-foil<\/a><\/p>\n

\t\t\t\t\t\t\t\t\t\t\t\tSummary<\/a><\/p>\n

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  1. Composition of a surf foil<\/a><\/li>\n
  2. Principles of operation of a foil<\/a><\/li>\n
  3. How the characteristics of the foil vary<\/a>\n
      \n
    1. Lift<\/a><\/li>\n
    2. Speed<\/a><\/li>\n
    3. Stability<\/a><\/li>\n
    4. Manoeuvrability<\/a><\/li>\n<\/ol>\n<\/li>\n
    5. Our S-Foil Development Choices<\/a><\/li>\n
    6. The influence of the board on the behaviour of the foil<\/a><\/li>\n
    7. Our surfboards and sup foil<\/a><\/li>\n<\/ol>\n

      Surf-Foil appeared in the 2000s. Among the pioneers are big names such as Laird Hamilton, Dave Kalama and Paolo Rista. Originally, it was just a way to fly over the water in a surf-towed way, in large waves of swell. In 2016, it was Kai Lenny who made the number of practitioners explode. The discipline immediately conquered surfers from Hawaii, Australia, California and Brazil. The level is skyrocketing. Gradually, surf foil arrives in Europe, and in France. The advantages of Foil are to multiply the number of possible sessions, practicable spots, and offer new sensations. In this article, we will explain how a surf foil works with its different parts and we will detail the importance of the characteristics of the front wing.<\/p>\n

      This article explains how a Foil works<\/strong> for the following sports: Surf Foil<\/a> , SUP Foil<\/a>, Downwind SUP Foil and Tow-in Foil<\/a> .<\/p>\n

      Composition of a Surf Foil<\/b><\/h2>\n

      The foil is composed of the following components<\/strong> : mast<\/strong>, fuselage<\/strong>, front wing<\/strong> and rear wing<\/strong> (stabilizer). <\/p>\n

      The mast<\/strong> is attached perpendicular to the plank and fuselage. Thus, the wings are parallel to the board. In this way, it is possible to act on the foil by simply pressing the feet. <\/p>\n

      The front fin has a domed upper part (upper surface) and a flatter lower part (lower surface). The front wing has a rounded leading edge that quickly builds thickness and then tapers to a thinner trailing edge. The width of the front wing (the width from the center of the leading edge to the center of the trailing edge) is called “the chord” and the length (the right\/left end) of the front wing is called “the chord”.<\/p>\n

      Finally, the stabilizer has a shape quite similar to that of the front wing, with equivalent properties. However, it has a small surface area and a different profile.<\/p>\n

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      Principles of operation of a foil<\/b><\/h2>\n

      The working principle of a surf foil is based on fluid dynamics. The front wing is pulled upwards as it moves forward, because the water molecules that pass over the upper surface of the front wing accelerate to catch up with the water molecules passed over the lower surface (which is shorter because it is flat). The acceleration of the molecules on the upper part of the wing creates a depression and the slowing down of those on the lower part creates overpressure. The consequence is an upward suction effect. The higher the speed of the foil, the more the foil is “pulled” upwards (at the same profile and angle).<\/p>\n

      We can easily compare the operation of a foil to that of an airplane which takes on more or less the same shape if we forget the mast and the board. Movement speed grows lift and allows take-off. The difference in angle given to the wings of an airplane Stabilizes in the air. LA decrease in the speed of movement allows you to reduce lift and therefore to land an aircraft (at a constant angle of incidence). Finally, to change the angles of incidence of the foil, the rider can by alternating pressure on the front or rear foot make the foil or the stability go up or down. It’s all about the amount of pressure on the supports. <\/p>\n

      To take off, the speed must be high enough to create lift force on the front wing. Combined with a high angle of incidence (thanks to pressure on the back foot) the board takes off. To stabilize the situation, pressure on the front leg reduces the angle of incidence, and therefore the lift, and accelerates.<\/p>\n

      Our best equipment for SURF FOIL<\/h2>\n

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      \n\t\t\t\t\t\t\t\"\"\t\t\t\t\t\t\t\t<\/a><\/p>\n

      S-Foil High Aspect 1350 Lift Front Wing<\/a><\/h2>\n

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      \n\t\t\t\t\t\t\t\"Le\t\t\t\t\t\t\t\t<\/a><\/p>\n

      S-Foil High Aspect 1190<\/a><\/h2>\n

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      Surf foil pack Fast Flyer + S-Foil High-aspect 1190<\/a><\/h2>\n

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      Surf Foil 4’6 Fast Flyer<\/a><\/h2>\n

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      \n\t\t\t\t\t<\/a><\/p>\n

      Swell as a source of energy<\/h3>\n

      If the aircraft uses the suction force of air molecules, the foil solicits the suction of water molecules that have a much higher density than those of air. This density will increase the lift (the upward suction effect) of the foil with speed.<\/p>\n

      In this article, we are talking about Surf Foil and the use of water movements (waves, swells, troughs, boat wakes) to fly. In contrast to wind, which allows the use of a constant force external to the water in kite or windfoil, the water movements of waves such as waves are variable forces with precisely localized lift zones on the water.<\/p>\n

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      It is therefore a question for the Surf Foil practitioner to leave lying on the board with the foil underneath and to paddle to catch a wave (in SUP Foil you go directly standing up and you paddle with the paddle to catch the wave). Once on the wave, the accumulation of speed generated by the slope of the wave allows the wave to take off.<\/p>\n

      Surf Foil and Downwind Foil in pictures
      <\/h3>\n

      \t\thttps:\/\/www.youtube.com\/watch?v=OdBDshTxmEAhttps:\/\/www.youtube.com\/watch?v=kVeWCkw94IQ
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      HOW THE CHARACTERISTICS OF THE FOIL VARY<\/b><\/h2>\n

      When it comes to fluid dynamics, every detail or change made to the foil matters and affects its characteristics. We looked at 4 major characteristics of a Surf Foil to explain what parameters influence them <\/em>(There are many others but we won’t cover them in this article).<\/i><\/p>\n

      Lift<\/b><\/h3>\n

      The lift of the foil, or the upward suction effect, varies mainly according to the size of the front wing, its thickness, its airfoil shape and the angle of incidence of the wing. The larger the surface area of a wing with the thickness, the more lift it generates. The higher the angle of incidence, the more lift it generates but slows down the foil. On the other hand, the lower these parameters, the lower the lift. With equal surfaces, angles and thicknesses, two different profiles will result in different lifts and speeds. The surface area as the only reference parameter is not enough to determine whether a foil carries a lot or not<\/strong>.<\/p>\n

      Indeed, the specificities of the front wing profile will play on the overall lift of the foil. This can be the upper curve of the upper surface or the lateral curve, i.e. the one that goes from side to side lengthwise.<\/p>\n

      Finally, other external elements play on the general lift of the Foil such as the weight of the rider, the weight and size of the board or of course the power of the waves.<\/p>\n

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      Speed<\/b><\/h3>\n

      In addition to the lift of the foil, the speed of the foil depends on the surface area and the angle of incidence of the front wing. A front wing with a small surface area and\/or little thickness will offer more speed, and a front wing with less angle of incidence will also be faster.<\/p>\n

      Then, the specificities of the shape of the wing for the same surface play on the speed of the foil. A wing with less chord and therefore more wingspan will be faster. In addition, the profile of the wing (parameters mentioned above) has a great influence on speed and acceleration ability.<\/p>\n

      Finally, as mentioned above: the weight of the rider, the size and weight of the board but also the power and speed of the swell are external factors that strongly condition the speed of the foil.<\/p>\n

      Stability<\/b><\/h3>\n

      A relatively slow foil with a lot of lift (i.e. large surface area, wing thickness and a bit of angle of incidence) will be more stable than a foil with less weight and a faster one.<\/p>\n

      The main elements that allow the foil to gain stability are the length (chord) of the front wing, its thickness and the surface area and wingspan of the rear wing, also known as the stabilizer.<\/p>\n

      The rear wing (stabilizer) plays its full role in stabilizing the foil. Its lift is inverse to that of the front wing and thus makes it possible to slightly counteract the lift of the front wing by creating opposing forces to stabilize the entire foil.<\/p>\n

      The external factors influencing the stability of the Foil are necessarily the weight of the rider and his technical skills but also the type of body of water on which Surf Foil is practiced. A rough body of water with currents, backwashes and waves will be more unstable because these elements disturb the depressions and overpressures that generate the pull of the foil upwards (like an aerial disturbance when you are in a plane).<\/p>\n

      Manoeuvrability<\/b><\/h3>\n

      If a foil with little lift (i.e. little surface area, angle of incidence and thickness) is faster and indirectly more manoeuvrable, this is not the only parameter that affects its manoeuvrability. <\/p>\n

      The main element concerning the manoeuvrability remains the shape of the front wing, namely the lateral curve, which accentuated makes it easier to turn with the foil. A high lateral curve will result in a more manoeuvrable but slower foil because for the same lift surface (shadow cast on the ground) the total surface area will be larger and will brake. On the other hand, a flatter side curve will rotate less but will be faster.<\/p>\n

      IN SHORT<\/b><\/h3>\n

      The general shape and dimensions of the foil vary these four characteristics:<\/p>\n