Surfboard Fins Explained

Surfboard fins explainedSurfboard fins explained, in this post I will discuss:

  • What are surfboards fins?
  • What does a surfboard fin do?
  • Parts/areas of a surfboard fin.
  • The Materials used to make surfboard fins.
  • The two major developers of surfboard fins.

What Are They?

Surfboard fins are the items that attached to the bottom tail portion of a surfboard.  They are either glassed on to a surfboard, which means they cannot be removed, or put on using the fins slots.  With fin slots, the surfboard fins can be installed and removed easily.

Based on my research, the main benefit to glassed-on fins are that their method of attachment is stronger than the removable fins.  Removable fins have many benefits over glassed-on fins, besides being easy to remove and install.

A surfboard with removal fins are easier to transport, no fins to get in the way.  Removal surfboard fins allows the surfer to change fins based on surf conditions.  If you break a fin, removal surfboard fins make changing out a broken fin very simple.  In the 1990s FCS, Fin Control Systems developed the first removable surfboard fin.

What’s The Purpose?

Surfboard fins helps the surfer control and steer a surfboard.  Early surfboards did not have fins.  Tom Blake is credited with inventing the first surfboard fin, and placed the first fin on a surfboard in the 1930s.  With his invention surfers could better control and maneuver their surfboards.

Simon Anderson invented the thruster aka 3 fin system in 1980 and used this newly invented system to win the Bells Beach surf contest in 1981.  The thruster system revolutionized the surfboard industry, allowing turns and maneuvers that were unheard of at that point in time.  As of today, the thruster system is still being used by professionals and amateurs surfers alike.

Anatomy Of A Surfboard Fin

Surfboard fins explained

Parts/Areas of a surfboard fin.

Per, these are the different parts/areas of a fin and how these parts/areas affects surfboard control and performance:

“(1) The depth is the measurement from the tip of the fin to the base of the surfboard, and it is essentially how far the fin goes into the water. The fin depth effects how the board “holds” in turns. The deeper the fin goes, the better the control is in the turn.

(2) The fin’s base length is measured at the widest point of the fin. The base length determines the board’s speed and drive. Fins contribute more speed and greater drive with longer base lengths.

(3) Rake — also known as sweep — is the distance the fin tip curves away from the base. The rake affects the turning ability of the board. The larger the rake is, the more maneuverable the board will be and the tighter the board will be able to turn. The smaller the rake is, the greater the drive and the less maneuverable the board will be.

Fin flex is the amount of movement of a fin from side to side. The stiffer the fin is, the less movement from side to side it will have, and thus the less Flex.  A stiffer fin leads to quicker turns and less drive a fin that has a lot of has greater drive.

Fin foil is the curve of the fin from front to back and from tip to base. The foil and fin thickness determines how much and where on the fin that flex takes place when turning. Different foils give the fin its different performance characteristics.”

What’s That?

Surfboard fins are made from many different materials, and these materials can affect the characteristics of fins.  The first fins were made from wood and were glassed-on to surfboards.  Wood fins are still being made today but are made more for their beauty than performance characteristics.

Rubber fins will not improve fins performance but will definitely protect a surfer from damage, these types of fins are found on foam and beginner boards.

Plastic fins, just like rubber fins, will not improve fins performance and are primarily used because they are inexpensive.  You will find these types of fins on foam boards and also the less expensive beginner surfboards.

Fiberglass, is the number one material that surfboards fins are constructed from.  Fiberglass can be purposely shaped and molded to affect fin performance.  Fiberglass is often combined with other materials to affect fin strength, weight and performance.

Aluminized fiberglass, carbon fiber, carbon Kevlar, etc. are all additional materials that are used to make surfboard fins (see:, and will affect the weight, strength, flex and performance of the fin.

There are also signature series fins, fins that are made with the professional surfers name and approval on these fins.  Mick Fanning, Jordy Smith, Joel Parkinson, John John Florence and Gabriel Medina are just some of professional surfers involved in signature series fins.

Surfboards fins are also designed with the weight of the surfer in mind (see:, the fins are sized: X-Small, Small, Medium and Large.

And Then There Were Two

Surfboard fins explained

Futures, FCS and FCS II

There are several makers and developers of surfboard fins but two companies have cornered the market.  The majority of surfboards will have either one or the other of their fins.  The two companies are Futures and FCS.  The main difference, though these companies may say otherwise, between Futures and FCS is the way in which they are installed into a surfboard fin slot.

Futures has a larger fin/surfboard attachment point and once installed into the surfboard fin slot, uses one screw to secure the fin to the board.  FCS has two fin/surfboard attachment points and once installed into the surfboard fin slots, uses two screws to secure the fin to the board.

I find Futures fins are harder to install than FCS, because they fit tightly into the fin slot but once in they are more secure.  FCS fins are easier to install and remove but, in my opinion, are not as secure as Futures because the fit is not as tight.

Surfboard fins explained

Surfboard key fin.

FCS has come out with the FCS II, which require no tools (aka surfboard fin key) to attach the fin to the surfboard.  However, based on personal experience, these fins can come out if they strike a hard surface.  Fins cannot be purchased one fin at a time, so, if you lose one fin, you’ll have to purchase a whole set.

Futures and FCS are both using space age materials and the latest technology to improve surfboard fins design and performance.

In Conclusion

Surfboard fins are used to control and steer a surfboard, and they are attached to the underside of the tail section of a surfboard.  They are made and designed from different materials which will affect their weight, strength, properties and performance.  There are several makers/developers of surfboard fins but two companies have cornered the market, Futures and FCS.

Click here to read my review of the FCS II Carver Performance Carbon Tri Fin Set.

Thanks for dropping in and if you have any questions or comments, please post it in the comments section of this page.

4 thoughts on “Surfboard Fins Explained

  1. Hi, Stuart. I enjoyed your article. I have always admired surfers, they seem to possess great balance and bravery. I never knew the ‘fins’ came off of the boards. Would the fins come off in the water, and would that cause injury to the surfer?
    Great post!

    • Hi Audra, Surfboard fins generally will not come off the board unless they break. Surfboards fins also do not float they will sink so, the chances of a surfer being injured by a fin that came off is rather slim. The fins are secured to the surfboard via screws, though some are tool less, go here to read my review on tool less fins.

      Thanks for the comments and dropping in!

  2. It is safe to say that everything I read on this post was all new to me! I do not know a single thing about surfing but I have wanted to try it. You helped me learn some neat information, thanks for putting all that hard work into writing this post. This site is very helpful, Ill be coming back to learn more!

    • Hi Summerly, I’m glad I provided you with information you did not know, and if you ever do decided to try surfing my “Getting started” page may prove useful.

      Thanks for the comments and dropping in!

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