A BRIEF HISTORY OF SURF FINS:
the 11 basic genes :
Impossible to evolve without keeping the best of our genes... Since 1934 (Tom Blake), fin designers have come up with various shapes with various purposes. We will cite here only 11 basic "genes" in the genealogy of the fin, because dozens of models deserve to be mentioned for their participation in this evolution. We have put aside the purely aesthetic factor, which nevertheless remains an important argument in an environment where fashion has strong roots. For a more in-depth study of the history of the fin, I invite you to consult the page
In the beginning, there were... waves and instinct:
Need creates fin function instinctively, varying the shapes of our hands to steer us through the wave. No historical trace of the inventor, we would have to look at the prehistoric level and certainly beyond in our genetic memory... or closer to us, in the feeling of the present moment.
Gene #1: Continuous variation of the shape of the fin according to the conditions.
Throughout history, each civilization of sinners has developed its own experience of waves and a way of riding them. We will therefore not discuss here the anteriority of the discovery because the instinct of sliding is universal. Accounts of travels in West Africa (1600) relate the agility of the canoe in the waves, in this case, the oar serves as a drift that is oriented to direct the canoe in the wave:
Gene #2: Variation of the incidence of the aileron according to the need.
The first surfboards observed during Cook's voyages (1769) to the Sandwich Islands describe long boards without fins, and the first photographs of surfers (1890)
show us an Alaia shape without fin.
Surfboards will remain finless for a long time, the rail being the only way to hang in the wave:
Gene #3: Here we will remember that hanging on the rail in gear, straight line, without transverse skidding, our drift should not slow us down and only be forgotten .
But the need to lean to modify the trajectory without skidding is very real, and to steer their longboard without drifting, surfers of the time (1930-1940) briefly dip their feet in the water to turn the board. The invention of the surfboard fin can be attributed to Tom Blake in 1934. Salute to this genius surfer who embodies the creative spirit of the shaper/surfer:
The installation of this fin revolutionizes surfing by allowing figures that were impossible before, it stabilizes the trajectory and leans on a rear pivot to turn and change direction. But despite its indisputable effectiveness, this innovation proposed by Blake in 1934, took time to be adopted because of its relative difficulty of implementation and the danger it constituted in the eyes of surfers of the time.
Handwritten photo and caption by Tom Blake.. Surfer Magazine, March 1981.
Gene #4: The fulcrum and the pivot allowing the turn, but we will also remember that a technological advance must include security and ease of integration to be shared..
From 1935 to 1960 the height of the fin continues to increase, the fulcrum is more and more effective and allows increasingly tight turns, the radicality of the cut back and the bottom turn is linked to this evolution:
Gene #5: The importance of the surface
In the 60s, the evolution of new materials allow greater elongations, and safety begins to become an argument, we will note in 1960 the POPOUT which is intended to be removed during an impact::
Gene #6: think about safety
Around 1964 as the Twin spread (A detailed explanation of why and what the twin does is given in the explanatory video of aileron dynamics), Greenought tested twin fins and systematically brought them closer together, as long as he got gain. efficiency, he ended up tightening them so much that he noticed that a single well-sized fin was more efficient! No the twin is not dead and the multi end still has a bright future ahead of it, but remember that more is not necessarily better
Gene #7: A good fin is better than two that contradict each other.
In the 1970s, Greenought developed single fins, of high aspect ratio: to allow increased maneuverability, it decreased the width (chord of the profile) which induces a rail effect, and it increased the length (reduction of vortex losses) to preserve the surface and therefore the support which is centered further forward of the board. at the same time it introduces Rake (backward angle) and flexibility, the combination of which allows the geometry to deform under stress.
The principle of Greenought: we lengthen and thin and give rake to bend the tip of the fin in the direction of the flow. A feeling of flexibility and fluidity in the maneuvers is thus introduced. This drive effect is proportional to the length of the fin, its rake and its flexibility.
Attention, the exaggeration of this principle generates:
- Long thin cutting sabers increasing the risk of cuts,
- Centers of lift offset from the board, producing tilting and overturning effects, reducing the grip of the rail.
- An inversion of the upper surface curvature which may cause the leading edge to stall.
Gene #8: the variable geometry according to the effort!
Gene #9 :
In 1977, Cundith worked on the structure which, combined with the material used, made it possible to manage the flexibility of the fin without generating excessively long drifts:
Gene #9:work of the structure to manage the deformation
In 1998 Swivel Fin introduced a concept of adjustable incidence which is certainly the result of a more scientific hydrodynamic approach to the performance of foils according to their incidence::
Gene #10: the importance of the angle of attack and its adaptation to generate optimum lift and minimum drag.
Around 1984-86, winglets appear at the end of the aileron, inspired by aeronautics, they make it possible to reduce the vortex losses at the end of the aileron, the winglet brings a gain for the ailerons with low elongation whose center of lift is close tip generates a lot of vortex losses, for large fins, the efficiency is lower and you have to be careful not to increase the dragged surface unnecessarily...
Gene #11: limit vortex losses when the lift concentration towards the tip is high
What future for surf fins?
The dynamic ADAC System™ technology, a variable geometry surf fin, an evolution resulting from the best of these genes, and the most advanced production techniques.