Surfboard Fin Technology
The base is the area between the front and the back of the fin. The amount of base determines the amount of drive and acceleration. The longer the base the more drive, acceleration and hold a fin will provide.
Depth refers to how much a fin penetrates the water and determines a board’s directional control. More drive and hold through turns is achieved through greater fin depth whilst shorter depth will accentuate speed and release.
Sweep is also referred to as “Rake”. It is the measuring of how far the lead edge (Front) of the fin is curved backwards. The amount of rake influences the length (or arc) of a turn, where less sweep allows for tight pivotal turns and an increased sweep allows the board to sustain longer turns.
The flex of the fin is critical to the performance! Stiffer, rigid fins are more responsive with increased drive and hold. Flexible fins are more forgiving and allow for a spring out of turns, however too much flex (such as some plastic fins) do not respond and destroy speed.
A flat foil refers to an even levelled surface on the inner side of the fin (flat inside fin). Traditional flat-foiled fins are formulated with a convex shape on the outer side of the fin, providing a well-balanced feel and trusted overall performance. The flat foil is often preferred in high performance surfboards (releases easier) and in powerful surf where creating additional speed is not required.
Inner foil is a complex hydrodynamic foil, characterised by a rounded leading edge, concave inner face and a convex on the outer face of the fin. Specifically designed to improve water flow dynamics over the fin by minimising drag and adding lift. The inner foil is utilised for increasing speed, hold (less release than flat foiled fins) and creating tighter turning arcs. A good option for surfers and surfboards needing more speed and hold.
A 50/50 foil is most commonly used in centre thruster fins and quad rear fins. A 50/50 foil is a symmetrical curve on both sides of the fin that evenly distributes the flow of water, delivering a smooth feel, increased stability and control.
80/20 70/30 FOIL
80/20 and 70/30 foils are generally used in side fins (2+1 set ups) in longboards and for quad rear fins. These foils deliver smooth rail-to-rail transitions whilst still offering bite and drive through turns. 80/20 Foils are the most popular option for Shapers performance quad rear fins.
The amount of drive produced by a fin is determined by its construction (material used), foil and template (particularly fin base). Fin drive is referred as the amount of forward acceleration the fin provides, making the surfboard surf faster with greater hold, control and power out of manoeuvres. The number allocated to a fin drive is out of 10, the higher the number the more drive the fin provides, the lower the number the more looser the board will feel. Carbon is a stiffer material than fibreglass, it loads up and then releases energy, hence providing more drive (Carbon Stealth, CarbonHybrid and Driver Series fins are renowned for providing greater drive).
Pivot refers to the length of the turning arc which is influenced by the rake (sweep angle) of the fin. The lower the pivot number allocated to a fin the more rake a fin has (such as the Carvn Series) and the longer and more drawn out the turn becomes (great for sweeping cutbacks and point break surfing). A fin with less rake will have a higher number allocated (like the Pivot Series) and will create a shorter turning arc, change direction quickly (more pivot) and surfs tighter in the pocket (a good choice for beach breaks and fast barrels).
RELEASE / HOLD
Hold refers to the amount of engagement the surfboard has to a wave, whilst release regards the board’s ability to break free of the wave through turns. A fin with a larger area, more height and rake will offer greater hold and overall control (less slide). A fin with a smaller surface area, less depth and that is more upright (less rake) will provide greater release. In addition, fin set ups that have a thinner tip or a smaller centre fin (such as the Shapers AM1) assist in offering greater ease through turns and fin release off the top.
Fin Flex is extremely important and makes a significant difference to a surfboards performance and the way you surf. Flex refers to the fins distortion from its original shape throughout a manoeuvre. Stiffer fins offer more drive and responsiveness, but are more difficult to turn. Flexible fins are more forgiving & offer a whipping sensation (squirt) out of turns, but can reduce drive and speed if too flexible. Shapers Fins is committed to the research and construction of fins utilising the most advanced materials and fin designs to control the flex and overall performance of our fins.