Fin Buyers Guide

Surfboard Fin Buyers Guide:
Base Type:
There are two main base types used on boards with replaceable fins:
Style:
Single Fin: A single fin box is most common on longboards and is the most traditional surfboard fin configuration. Turning with a single fin is limited, meaning single fins are ideal for fast, straight shot surfing. Single fins will provide stability, control, and predictability to your longboard. Longboard single fin boxes are long and allow you to move the fin forward for a looser feel, or further back for more control.


2 Plus 1: 2 plus 1 configurations have a longboard single fin box in the middle, with 2 regular thruster side fin boxes to each side. The middle box is longer, allowing you to set your middle fin forward or back. This is an increasingly popular fin box configuration on eggs, fun-boards, SUPs and logs.


Twin: Twin fins or a dual fin configuration will make your surfboard fun, playful, and maneuverable. Two fin setups are not ideal for big-wave riding and are commonly featured on short-boards to enhance their speed. Twin fins offer a skatier feel and longer, more drawn out turns.


Thruster: The thruster setup is the most common configuration and can be found on a number of shapes and sizes. The front fins areangled towards the board center and are typically flat foiled to increase lift (hold). The center fin is symmetric on both sides (50/50 Foil) for stability.


Quad: Quad configurations allow more speed in small surf by increasing the hold by increasing the surface area of the foiling towards the rail and will increase stability.


5 Fin: Five fin configurations are typically ridden as a thruster or quad however in some cases they will be used as a quad with a "knubster" fin in the rear center. The smaller knubster fin increases stability without adding drag.
Size / Template:
Base- Is the length of the part of the fin that touches the board. The longer the base the more drive and lift.

Depth/Height- Is how far the fin sticks in the water. The deeper the fin the more hold, the shorter the depth the less hold. Shorter fins will have a looser feeling and will be easier to turn.

Area- Is the surface area of the fin. In general, more area = more hold.

Sweep/Rake: Refers to how far back the tip of the fin sits in relation to the base. Less sweep give more pivot while more sweep the more rounded turns will be.

Hold/Release: The fuller the tip of the fin the more hold it will have, the narrower the tip the more release.

Cant: Fin Cant is the degree of outward angle a fin has in relation to the bottom of your surfboard. If a fin has zero cant its position straight up and down at a right angle to your board. This is going to be fast in a straight line, but it wont give you as much responsiveness through turns. If the cant of your fin is larger, your going to gain a little more of that responsiveness through your turns. It means you can maintain some more drive when your board is tilted on the rail.

Toe: The toe of your fins set up is relating to the angle that your fins are pointing at towards the stringer. This occurs a lot in side fins with the front of the fins pointing towards the center of your board. This can help create pressure on the outside foil of the fin. This in turn, allows you to again have a little more responsiveness on your board.
Materials:
Honeycomb/Performance Core (PC):

The NVS honeycomb / hexcore series is designed to deliver the dynamic performance of traditional fiberglass fins, while eliminating unnecessary weight. Our Resin Transfer Molding (RTM) process yields a lightweight fin that optimally balances flex, drive and responsiveness for high speed, performance surfing. These sext fins are the go to, high performance choice for any of the NVS team riders.

Carbon Fiber:

Carbon fiber has one of the best strength-to-weight ratios of any composite material currently on the market. Carbon fiber's strength, along with its lightweight heat resistant properties have let to innovative use in numerous industries. On NVS Fins, the carbon fiver overlay allows for increased strength without sacrificing fin responsiveness or flex. Using carbon fiber in combination with the Honeycomb, Resin Transfer Molding process yields extremely durable lightweight, high performance fins.

Bamboo (Eco Series):

The EcoSeries fins have been designed with both maximal performance and minimal environmental impact in mind. A Natural bamboo core decreases the overall weight of the fins without sacrificing strength and flex. Bamboo actually has higher tensile and compression strength than steel. It is also the fastest growing woody plant on earth, making it a more sustainable material than conventional fin cores. The use of Bamboo is taking pressure off old growth hardwood forests, and reducing environmental toxins commonly associated with the harvest of traditional woods. NVS is dedicated to minimizing negative environmental impact, our EcoSeries is another step in that direction.

Composite / Neo Glass / Glass Flex / Thermotech: Made from a composite mix of materials to give desired characteristics. Many of these fins in this category have a softer flex pattern than more performance oriented fins. Availalble with variable flex patterns, most are less than ideal.
Foils:
Foil refers to the shape and geometry of the inside and outside faces of the fin. Foils directly affect the flow of water over the surface of the fin. Below are the standard types of foil but not all foils are created equally (we'll address this below)

Flat: A flat inside face combined with a convex outside face. The traditional flat-sided foil offers an even combination of drive, pivot and hold and provides a very consistent, reliable feel over a wide variety of conditions.

Inside: A foil consisting of a convex outside foil; a rounded leading edge; and a concave inside foil. Inside foils have more lift at slow speeds but as wave speed increases they produce more drag than flat foils. Not the best option for faster waves. 

50/50 (symmetrical): A symmetrical foil used on all center fins where both sides are convex. Even water flow on both sides creates stability and control. Used of some quad trailers to give a looser feeling.

80/20: Combines the performance of a center and side fin offering increased speed, smooth rail-to-rail transitions and a consistent feel in a variety of conditions. Used as trailers for Quad setups.
NVS Series-II vs Series-III Foils
At NVS we're constantly working to imporove the performance of the fins we offer. Using research from NACA on the fluid dynamics of differnt types of foils we've improved upon the standard foiling available on fins.

Series III foils are based off NACA foils and are designed to increase laminar flow while decreasing turbulent flow (Drag). The SeriesIII foils have a higher range of angle of attack to limit speed loss while turning.


Series II The SeriesII foiling is a more traditional surfboard foil. This foil produces lots of lift at slow speeds but doesn't hold as much speed through turns when compared to our hydrodynamic SeriesIII foiling.


It's been said if you don't like your surfboard; change your fins.
- Is the board too stiff? Try changing to a fin with less surface area or less sweep
- Is the board too loose? Try a larger or stiffer fin. Increasing sweep will make turns longer and more drawn out
- Soft or looser boards will go faster and have better drive when paired with large fins with ample rake
- Larger surfers typically need larger fins, smaller surfers -> smaller fins
- If you want a more responsive board choose fins that are stiffer
- Boards with more rail or with fins closer together typically need less surface area
- Boards with a lot of rocker may need fins with larger area sweep or depth
- If your board has channels built into the bottom side you can use a smaller fin (the channels act as small fins)
- Boards with wide tails typically use fins that have more area
- Small boards in larger surf typically use larger fins with greater sweep