HOW TO CHOOSE THE RIGHT SURFBOARD FINS
The number of factors that affect how a surfboard performs is abundant, and fins play a huge part in the results. Tinkering with the fin setup on you new or go-to boards can open up new possibilities, and ultimately improve your surfing performance. The collection of fins we offer is the result of decades of experimentation and refinement, and the bottom line is that as your relationship with your fins expands and progresses so will your surfing ability. Here is a basic surf fin guide to help you choose the right fins.
STEPS TO SELECTING SURFBOARD FINS...
Step 1: Determine Configuration
- Single Fin, 2+1, Twin, Tri, Quad or Twinzer etc.
Step 2: Determine Compatibility
- Center Box for Single Fin, Futures Compatible, FCS Compatible, Glass On
Step 3: Learn About Fin Design & Terminology
- Understand the basic principles of fin design such as the importance of template, area, rake, flex, foil, toe, and cant.
Step 4: Learn About Key Design Attributes & Function
- Understand the core elements that dictate function and how a fin will perform.
Step 5: Select Based on Function & Design
- Use all of the knowledge you've learned to make a selection based on your surfboard, desired function, performance preferences, and the waves you're surfing.
FIN SETUPS & CONFIGURATIONS
There are lots of options when it comes to surfboard fin setups — single fins, twin fins, tri fins, quads... and the list goes on. A basic understanding of the performance characteristics of established fin setups will go a long way in choosing fins that are right for you. The first thing you need to do before selecting fins, is to check out the bottom of your surfboard near the tail and figure out what sort of fin configuration you have. Here is a list of some of the most common options:
SINGLE FINS
The single fin is the original fin setup, and its characteristic tendency for smooth lines and free-flowing maneuvers permanently reserve its place in the lineup. Single fins have a broad range of applications from longboards to mid-lengths, shortboards, edge boards, and even big-wave guns. Single fin size, template, area, and flex are all variable factors when making a selection.
2+1 FINS
As an elaboration on a single fin, a 2 + 1 retains the smooth feel, but with the added drive, hold, and stability that you'll gain from adding side bites. This setup features a single fin box in the center and side bite boxes forward and on either side near the rails. Popular on high-pro longboards and mid-length desings, the 2+1 offers versatility in a wide range of surf.
TWIN FINS
With a searing blend of smooth speed and maneuverability, twin fins deliver a unique set of enviable performance characteristics. Twin fins are generally drivey, but also skatey and loose with a wide point of release. Twin fins are set near the rail on both sides of a board. Within the world of twins there are many template options ranging from raked out keels to upright performance designs.
TRI-FINS (THRUSTER)
The tri-fin or thruster, has been the standard in high performance surfing for the past 40 years due to it providing the ultimate blend of speed, control, and maneuverability in critical waves or sections. The two fins set towards the rail are generally slightly toed-in and have either a flat or minimal inside foil. The center trailing fin is set closer to the tail of the board and symmetrically foiled.
QUAD FINS
Quads provide a desirable combination of speed, drive, and hold that will provide performance while maintaining and also producing “down the line” speed. The front fins are generally larger are set outside the rear and smaller trailing fins which work in tandem to channel water. Quads offer speed generation in smaller surf, and stability and hold in larger waves.
TWINZER FINS
Twinzer fins are an interesting middle spot between a twin and a quad and the setup draws on some of the best aspects of both. You get a bit more bite than a twin, drive like a quad, but also freedom, performance and control not quite like either. Twinzers have a smaller front fin known as a canard set close to the rail and larger rear fins set just behind. Learn more about Twinzers here.
ASYMMETRICAL FINS
Asym fins are in a specific category of their own, usually built for intentionally designed asymmetrical surfboards. The setup generally consists of a larger style twin fin design to be used on your toe side to provide lots of speed and drive, and then smaller quad style fins to be used on the heel side that provide maneuverability and a tighter turning radius in the pocket.
BONZER FINS
The Bonzer might be lesser-known, but this configuration is a supremely viable option for high-performance power surfing. A unique cluster of 3 or 5 fins offers hydrodynamic flow like no other surfboard design. Bonzer side fins, aka "bonzer runners" come as a set of 2, or set of 4 and feature a large amount of cant. The bonzer center fin is offered in five sizes with full base and mellow rake.
FIN BASE COMPATABILITY
A general familiarity with each type of base and the corresponding fin box (or lack there of) will equip you to confidently choose fins that are compatible with your board. At True Ames we sell surfboard fins that are compatible with single fin boxes (i.e. US Bahne Box), Futures boxes, FCS boxes, and of course glass ons which don't utilize any sort of fin box.
SINGLE FIN BOX COMPATIBLE (Shop Here)
The single fin box is an industry standard that allows for easy non-permanent installation for single fins. These boxes come in five different sizes and can accommodate any single fin with a roll pin, and a tab that has a screw and plate (the way that all of our single fins are made). Simply slide the roll pin, sometimes located on the front or the rear of the fin base, in the center slot and then shimmy the fin along the channel to your desired location. The fin is the held down through a metal plate slotted at the bottom of the channel and a screw that inserts through a hole in the tab of the fin base.
FUTURES COMPATIBLE (Shop Here)
Futures fin boxes come in two standard sizes (or depths) for what is referred to as a "full-base system." The first size has a box depth of 3/4" typically used for twin fins, front side fins for a tri, front fins for a quad, or rear fins for a twinzer. The second size has a box depth of 1/2" as is typically used for the trailing fin of a tri, the trailing fins of a quad, or for a small center trailer for twin setups etc. Futures compatible fins are held in place with a single grub screw that you tighten at the front of the box. Futures compatible fins generally have the angle or designed cant built into the fin and not the fin box.
FCS COMPATIBLE (Shop Here)
FCS fin boxes are generally peanut shaped and feature two slots for what is referred to as the two tab system. The tabs slide right into the slots, and then traditional FCS compatible fins are secured in place using two grub screws that are tightened to hold the fin in place. True Ames produces fins with traditional FCS tabs which work in both the classic FCS boxes and also the FCS II system. FCS fins generally do not have any angle built into the fins or tabs (barring a few specialty items), as FCS boxes are available with different degrees of cant.
GLASS ON (Shop Here)
Glass on fins are used just like you think they might be - they're glassed on directly to the surfboard as part of the lamination process. Glassing fins on was the original and classic way to install fins and provides a seamless marriage of the two, in turn optimizing strength and reducing drag with unencumbered waterflow. Many folks still cherish boards built with glass on fins, not only because they highlight beautiful craftsmanship, but also because of the intrinsic performance and solid fin-to-board connection and feeling you get from that.
FIN DESIGN & TERMINOLOGY
Being familiar with basic surfboard fin theory and terminology is the foundation for deciding which fin(s) might best facilitate your style of surfing. More specifically, understanding the following concepts will help you sort through the True Ames collection of fins.
TEMPLATE: The 'template' of a surfboard fin is the outline of the fin. Each True Ames fin model is based on a template that has been designed using decades of experience and knowledge alongside our partners, and has proven itself where it most counts: in the water. The overall shape of a design really dictates a lot of the function and performance and is somewhat of an overarching concept containing some of the following attributes such as area and rake.
AREA: The area of a fin can be described as the amount of area inside the outline – or template – of a fin. And you might apply your geometry skills to note that the length of the fin’s base, and its height (i.e. depth) are closely related to the the area. In general, more area equates to more hold and drive, and less area equates to a faster, looser ride.
RAKE: An easy way to the think about rake is how “swept back” as opposed to “upright” the stature of a fin is. The more “swept back” a fin is, the more rake it has. A more technical definition is the angle between a line that runs parallel to the base of the fin, and a line that runs through the front corner of the fin and the tip of the fin. More rake will deliver more stability and a tendency for long drawn out turns, while less rake will deliver a more sensitive ride with a tighter turning radius.
FLEX: In the most basic terms, the flex of a fin is how much it will either bend or twist side-to-side. More precisely, the flex of a fin is a description of how the fin flexes perpendicular to the direction of flow. Important qualities are how much force it takes to flex the fin (i.e. how stiff the flex is), and how quickly and reliably the fin returns to center. At True Ames, our craftsmanship and materials produce fins with consistent flex that quickly and reliably return to center, and with this as our starting point, we make each fin design with the optimal amount of stiffness.
FOIL: The foil of a fin can be described as the contours of the fin when viewed from an “edge-on” perspective. Similar to how the foil of an airplane wing affects the flow of air as it passes the wing, the foil of a fin affects the flow of water. A 50/50 foil has symmetrical contours on either side, and this will be the case for all of our single fins. Within our system fin collection, you may find anything from 50/50 foils to 70/30 foils to flat inside foils. Whatever the foil ratio is, all True Ames fins feature continuous foils with the thickest section of the foil towards the center of the fin, and thinner sections at leading and trailing edges. Foil plays an important role in producing lift and thus speed.
TOE: Relevant to all types of side fins, toe is basically how much the side fins are pointed in towards the stringer. In other words, it is the measurement of the angle between the line that runs parallel to the stringer and the line that runs parallel to the base of the fin. If these two lines are parallel, the fin has no toe, or in other words they are pointed straight forward. Often fins will be “toed-in” by a few degrees, which results in enhanced control and maneuverability, while fins with no toe maximize speed by causing the least amount of resistance to water flow.
CANT: Cant is a measurement of how much a fin leans out towards the rail of the board. Or more precisely, how many degrees away from perpendicular to the bottom of the board the fin is. As a rule of thumb, center fins have no cant, and side fins have a few degrees of cant. However, there are some side fins that feature no cant. No cant on your side fins maximizes speed by causing the least amount of resistance to water flow, while some cant on your side fins will give you more control, and heightened maneuverability especially during turns. More cant generally = more lift, but also more drag.
KEY ATTRIBUTES, THEORY & FUNCTIONALITY
UNDERSTANDING KEY ATTRIBUTES
Rake: More rake, when looking at the fin's template or outline, will deliver more stability and a tendency for longer drawn out turns. On the other hand, less rake will deliver a more sensitive ride with a tighter turning radius.
Area: In general, more area equates to increased hold, drive, and stability - while less area equates to a faster and looser ride.
Drive: Drive is determined by the fin's (or cluster of fins) ability to create speed. In general, a faster moving fin is creating more lift than similar, though slower counterparts. Lift, which in turn produces drive, is generated from the way in which a fin’s template, base width, rake, foil, flex, and area are all working together and interatacting with the water.
Flex: A stiffer will have a more controlled and solid feel with quick response and sensitivity, while a fin with a lot of flex will often feel a bit looser and provide a subtly delayed response - often with increased projection.
ADDITIONAL DESCRIPTORS & FUNCTIONALITIES EXPLAINED
Base Width: A fin with a wider base will increase stability, projection and drive - while a fin with a narrow base will allow for easier and tighter turning capability, less drag, but also perhaps less power. Generally a wider base will produce more speed, while a smaller base will increase maneuverability.
Pivot: A pivot fin design will usually have some distinct characteristics. First and foremost, the stature of a pivot style fin is going to be upright with a minimal amount of rake allowing for a tight ‘turning’ radius. Essentially, this fin design will act as a pivot point, or anchor from which small adjustments and redirections can be made while using a minimal amount of the surfboard’s rail. The second attribute commonly associated with a pivot fin is a larger amount of surface area. The large amount of area provides stability, hold, and will lock the tail of the board in place. The pivot concept can be applied to both single fins and system (Futures & FCS compatible) fins.
Stability: The stability of a fin is related to the amount of resistance that fin (or fin's) provide. When we think about stability we often consider the fin's dependability, or the way in which a fin reliably performs - providing added support in the same predictable manner. Generally, a large fin with a lot of area, base width, width towards the tip, rake, and minimal flex is going to provide maximum stability. On the other hand... a fin that is upright in stature, with minimal area, a narrow base, a narrow tip, and a lot of flex is going to be much less stable. In principle, all fins are designed to provide some level of stability - but the amount varies greatly.
Lift: In relation to fins, lift is produced via the differences in surface pressures from one side of a fin versus the other and how they're interacting with the water. The flat side of a fin and foiled surfaces behave differently when passing through water and will produce lift in a specific direction - generally outward toward the wave face. There are multiple factors that can affect the amount of generated lift such as the size of the fin, the foil thicknesses, the angle of attack, the amount of cant etc.. Lift is used to generate speed and drive, but it is a balancing act because as lift increases so does the potential drag. Lift is also utilized to obviously assist with engaging the board's rail in the wave face. When a surfer pushes off the fin(s), acceleration occurs due to the lift and amount of pressure that is applied in a certain direction and thus helps with turning, stability, and increasing momentum.
Power: In general, when we talk about power, we are speaking about the ability to generate lift or drive. Increased power is achieved as there is more lift or drive created. Well-balanced fins with moderate-to-full base width, rake, area, and stiff flex will provide added power.
Turning & Maneuverability: Turning ability is often associated with a fin’s amount of rake, the overall area, and the shape of the template in general. More rake equates to longer drawn out turns, while less rake will result in more pivot. A larger amount of surface area makes it harder to turn, while a more minimal profile will result in the ability for a tighter turning radius. A fin that has a balanced amount of both rake and area will provide the best turning ability in relation to power, drive, and maneuverability.
MAKE A SELECTION BASED ON BOARD DESIGN AND FUNCTION
Equipped with the knowledge that you've gained above, you can now take a look at making a decision about what fins might be best for you. The world of fins is a vast one and there really are so many different elements to play around and mess with - and even then a lot of it still boils down to personal preference. There is no wrong answer! Often times, when narrowing down the options, there will be what we like to refer to as the 'left, right, and center' approach - meaning that there is a baseline and then options that provide functionality in one direction or the other. I.e, think about a medium size and profile fin, you could go with a smaller base and more narrow fin option to the left, or you could go with a wider base and fuller profile to the right which will of course provide different levels of functionality. To simplify things slightly, we created a very generic and baseline guide for you below with some of our favorite go-to 'center of the road' option choices per category. Check it out...
SINGLE FINS
Single Fins: The single fin setup is tried and true and can be very versatile depending on the board and fin selection. Within the True Ames catalog, we offer a wide variety of single fins built for different use cases and purposes. When it comes to single fins, there a few general categories for which we'll make some go-to recommendations:
All Around - Great for all cases and purposes with the most versatility across a broad range:
Flex Fins - added spring, projection, liveliness, and maneuverability:
Noseriders - Designed for large boards, logs, and you guessed - noseriding:
TWIN FINS
Twin Fins: Twin fins offer a lot of freedom due to the lack of a center trailing fin, and also rely on a lot of rail engagement. The lift generated from the larger surface area twin fins helps compensate for the typically shorter rail lines of a twin. Twin fins are generally fast and skatey. Recommendations based on general categories:
Fish - Generally paired with keel style fins, fish have a wide outline well suited for larger fins:
High Performance - Fins built for off the bottom & off the top type surfing and lots of turnability:
Hybrid - Fuller than an upright performance twin, but less area than a traditional keel:
- Ryan Burch Twin
- Furrow Twin
TRI FINS (Thruster)
Tri Fins (Thruster): The thruster combines all the functionality of a twin fin and a single. The center fin acts a pivot point while the toe, cant, and foil of the side fins generate drive and lift. Widely known as the highest performance fin configuration available. Here are some recommendations:
Performance - Combines all of the necessary elements needed for critical surfing:
All Around - Great for a varitey of boards, experience levels, and surf conditions:
Mid-lengnths / Gliders - Designed for larger boards, mid-lengths, and cruisers:
QUAD FINS
Quad Fins: Quad fins are somewhat like an elaboration on twins, providing a lot of rail engagement and often stability. Quads excel on smaller boards in smaller surf, or also bigger boards in waves of consequence and barrels. Baseline recommendations:
All Around - Great for a variety of boards, experience levels, and surf conditions:
Fish / Hybrid - Fins built fish, mid-lengths, and egg type boards:
Performance - Fins built for quality waves, critical turns and in the pocket type surfing:
TWINZER FINS
Twinzer Fins: The twinzer setup beautifully balances performance, flow, and speed in a tidy little package. The front canard fins break the water tension, while the larger rear fins generate additional lift, drive, and control. More bite than a twin, but more freedom than a quad. Check out some of our offering below:
Performance - Combines all of the necessary elements needed for critical surfing:
All Around - Great for a varitey of boards, experience levels, and surf conditions:
Specialty - Designed for larger boards, mid-lengths, and cruisers:
FAQ's
What size single fin do I need?
The size of your single fin can be determined by a variety of factors - but it always comes down to personal preference. The general general old school rule of thumb is for every foot of length for your board, it should equate to an inch in height for your fin. For example a 9 foot board would work well with a 9 inch fin… but there are a multitude of other factors that come into consideration, like tail width, the rider’s weight, type of board, type of surfing etc. Additionally, if you're pairing a single fin with side bites, then the center fin size should be decreased as you're adding additional surface area.
Where should I place my single fin in the box?
Placement of a single fin the box can greatly change the feeling of your surfboard. Placing the fin forward creates a loose feeling, which makes it easier to turn your board by shortening the radius in which the board pivots. Putting the fin towards the rear of the box will stiffen the board up, adding control and drawing turns out longer. We always recommend playing around with the location of your single fin, slide it up for one session and back the next until you find that sweet spot!
Does my surfboard size matter?
Yes - the overall shape, length, thickness etc. are all factors in making a decision. Generally, larger boards like longboards can use larger fins (although there are exceptions such as gliders), and smaller boards can use smaller fins. Tail width is also an interesting consideration in relation to board size, and there is commonly a correlation between the distance from the stringer or fin box to the edge of the rail and a similar size fin that you might need.
Does the size of the surfer matter?
Weight plays an important role when deciding the size of a fin, especially fins you’d be using for a multi-finned board. For tri-fins, the general weight-to-size range would be; Size S (>130 lbs), size M (130 lbs - 170 lbs), size L (170 lbs +). When determining the size of a single fin, weight is further down the list for contributing factors but still should be considered to a degree. For example, those on the smaller size might use a single fin only .5" or .75" different than someone on the other side of the scale. Weight contributes towards strength and overall displacement, so generally larger surfers can use slightly larger or stronger fins whereas smaller surfers can use less fin or more flex.
Does wave type or size matter?
Absolutely! Fin and surfboard designs are more often than not created to compliment a type of wave. For instance; a more upright fin (less rake) will provide your board with a tighter-arcing radius is usually the standard for smaller, mushier waves when sections are smaller versus a fin with more rake which will draw out your turns which would compliment a larger, more slopey wave. Often times larger and stiffer fins will provide more stability and hold as well for larger waves. When the waves are smaller and not as powerful you may want to be careful not to over-fin your board because it can start to feel sluggish and slow. Additionally, configuration will play a huge role in performance based on wave height. For example twin fins are fast and skatey in smaller surf, but might not provide sufficient hold like a quad or tri would in larger waves.
Does fin box placement or location matter?
Yes - this is often determined by the shaper or folks building the surfboards. Fin placement is very important and can effect the boards performance just like selecting different fins. Once a board is made, there is not much to do about this - but for informational purposes... fins further back on a board will give the board more control, while fins placed further up from the tail will make it feel looser. The amount of toe or cant will of course greatly affect the speed, lift, and maneuverability in addition.
Are bigger or smaller fins better?
There is no right or correct answer here! Personal preference plays a huge role in what sort of feeling you like for your board, but generally larger fins with provide more stability and grip while smaller fins will be more loose and skatey.
