Guide on how to choose twin fin and explanation about what are they used for

Let’s start with facts and explanations.

Twin fin is a type of fins, and they differ from ordinary ones in size and number (there are only two of them). But sometimes there is a small central paddle in the kit, the so-called stabilizer, so that the tail of the surfboard does not wag too much.

Earlier, when I heard about these twins, I imagined a plump surfboard with a fish (dovetail) and the 70s: people slowly ride the waves without sharp turns, and did not attribute twin fins to competitive surfing at all.

FCS II fins

Not so long ago, having arrived in Japan to the International Junior Surfing Games (ISA JUNIOR), I saw a picture that reminded me of Lake Ladoga: the waves were waist-deep, very weak and few people could show anything on them, except for the youngest riders that weigh like a feather.

I lacked speed on these waves, but it was not at all a board, because I used my favorite Spam with a huge double concave on the bottom (when the board in the middle has a convex shape and concave closer to the edges) – it was the best option of the three models that I brought with me.

And then I began to read all about the FCS II twins, looked at different models from the pro, and when I came to the store near the spot, I noticed two large twins at the very bottom of the rack.

I just wanted to buy them, but I didn’t.

I decided to ask the coach for advice, but he was skeptical about my idea, they say, there will be speed, and the ability to make vertical turns (on which we made the greatest emphasis) is hardly. But the fins solved the speed problem and I bought them myself.

Imagine my surprise when I also took out a small stabilizer fin! And rather I went to test the purchase.

The FCS II MR Twin

At first I had a strange sensation: when I raked, the tail of the board wagged very much, but at the same time, even the speed in moving along the lineup and in rowing was added a lot.

First wave: a fast wall and then a shallow part, I dash forward to speed and literally fly, fly over the closing section and do a big carve.

The first thought: “Yes, it can’t be!” The second, third wave: there is a lot of speed, and at the same time the tail does not wag as much as I expected!

From carves and cutbacks, I decided to switch to vertical maneuvers, and it was magical!

When you push the back of the board a little bit, the twin paddles immediately break off, creating a huge spray, a couple of times they scrolled too much and I was already going 360, but the wave force was not enough to turn me around.

By this time, everyone had already entered the water and sat on 3 peaks, 300 “hungry” surfers! Everyone sat on the edges of the peaks, as the waves closed very quickly at the beginning, and then went slowly.

I just sat down on the peak and started leaving one by one. Imagine the surprise of my Argentine acquaintances when I passed the section without problems, and they could not always pass it.

That’s how I fell in love with twin paddles.

Twin paddle on the hit

Twin fins surfboard

The evening before the hit, I was very worried: strong rivals, small waves and just the very fact of competition…

I wandered across the expanse of YouTube surfing, watching various videos, and found one very interesting: Kelly Slater on the Pipe Line in the 90s and 2016.

The size of his board surprised me a lot, on waves of 3-4 overheads he rode a 5`8“ board, whereas in the past he used large and long boards, and I realized that now you can have one board, the whole question is in paddles.

I decided on a non-standard solution, putting these twin to  the hit, the coach supported me.

My hit: I follow my strategy, and 2 minutes before the end of the hit I’m in first place with a couple of vertical quick maneuvers. And now the Costa Rican takes the wave, tk. he has priority, and I become the second, but with the first priority.

I made a mistake and gave the wave to the Spaniard, who literally snatched the victory in the last 5 seconds.

I was very upset with my strategy, but happy with my choice of Finns. I used these fins on almost all hits, and after that many trainers were interested in my choice.

Twin flippers are very good at maintaining and increasing speed and help you jump over places where the wave fades completely. And to Russian waves, I think they are almost the perfect choice.

twin surfboard fins

Surfboard flippers, aka finns (fins), are an important element of surfing equipment.

Ask the average surfer how he chose his twin flippers, and you’ll hardly get a thoughtful, detailed answer as to why he chose these surfboard twins over any other.

This is sad.

After all, the shape of the twins, their number and location on the board are very important, and this can be useful in how the board will behave on a particular wave, how it will behave at the rider’s work, how it will turn, and how quickly it will slide on the surface.



And I will sum it up: two flippers with a stabilizer are ideal for waves from knee to height – one and a half. On big ones they are not so good, here it is better to put four fins and fly.

Twins allow you to do all the tricks: carve, cutback, vertical reentry, snap, all airs and even pipes, but if these pipes do not come from the start, then they only work in the back side.

Ideal for boards with double concave and fish tail or boards for small waves (also called summer boards).

Twin fin gives not only speed and drive, but also a huge amount of fun.

They will go for everyone who takes the waves himself, and rides along the wave, trying to make turns, and for the level of riding higher.

If you have been sup-boarding for years, then you are probably constantly looking for the right equipment, spare parts and other components for comfortable rowing in any conditions.

So let’s look at one small but very important detail – the twin flipper, which is present on every board and has a special role – stabilizes the board as you move and helps you reach the desired direction and develop speed.

Twin’s design

Fin design

Before getting into an overview of the different twins, let’s take a closer look at what this important detail consists of.

Outwardly, it looks quite simple, but each part of it has a specific function, and manufacturers of different models change these parts to get the expected result when installing one or another fin on a pad.

The base or base is the top of the rib that is used to fit the twin into the mount. This is usually the widest part of the fin and helps stabilize the board and helps maintain course.

The other end of the rider fin is called the Tip (tip), which goes down into the water. It also, like the base unit, affects course maintenance and speed.

The leading edge (leading edge) is the front of the fin. It will affect how the board turns, as well as how quickly it cuts the water.

The trailing edge of the blade (tail) is the back of the twin paddle, and it also affects how easily or not the board turns.

This part helps to more or less release water, which affects the speed of movement.

What are twin flippers

What are these same fins (or fin – from the English fin)?

Removable, non-removable, flexible, rigid, plastic, fiberglass… The list is endless.

Let’s start with those presented on the universal inflatable paddleboards. They are usually equipped with 3 fin: side fin and center flipper.

Most of the inflatable bucks on the market are offered with non-removable side fin and removable center fin. This helps to roll the board more compactly after use. Also, world brands make inflatable bucks with one central removable fin.

More directional models (meaning for a specific direction of SUP boarding) are equipped mainly with a central fin, which can change depending on the desires of the rider and the conditions on the water.

What are they attached to

surfboard fin attached

Detachable fins are attached to US BOX or SLIDE AND LOCK mounts. There are also classic surf bindings FCS and Future Fins, which have begun to be actively used for supboards.

US BOX is a fastener with a special bolt. In principle, the system is not bad, but it is these bolts that are most often lost, so it is always better to have at least one in reserve with you.

Now an updated version of the US BOX has appeared on the market: in it a threaded hole is built into the mount itself, and the bolt is fixed to the fin. This allows you to get rid of unnecessary losses.

These systems are now being installed on many boards and will likely supplant others.

SLIDE AND LOCK bindings also perform their function perfectly, but for this type there is only one type of fin, which is installed only on inflatable bucks.

As for the fixed twins, they interfere with the compact folding of the board. And if the fin vomited from the base of the board, then returning it to its place will be very difficult and only in a boat workshop.

What are fins made of

surfboard fins made of

Twins can be made of different materials: from the simplest plastic to expensive fiberglass and carbon fiber, which are chosen by professional riders.

Oftentimes, when you purchase an all-in-one walking kit, you immediately get a standard 9 ”fin made of durable plastic that will meet all your needs.

Fin shapes

surfboard fin shapes

Twins differ in shape. The standard Fin Dolphin complete with an inflatable board really resembles a dolphin’s fin in shape.

It helps the board to stay stable on the course during your movements, agrees with the maneuvers that you carry out, can be used for any kind of SUP boarding: surfing, touring, walking, racing, but as long as you do it on an amateur level.

To progress in one of these areas, it is necessary to acquire more suitable equipment.

Looking at each fin in terms of surface area, here are the pros and cons of each type:

  • Twins with a wider base and longer leading edge will give you better course control and help stabilize your board, making it less sloped and more predictable in choppy water. On the other hand, this paddle will cut water worse, so it will take more effort to turn the board around as there will be more resistance to water flow around the paddle.
  • Twin with a smaller surface area with a narrow base and a short leading edge will turn more easily and allow the board to move faster through the water. However, such a fin will not keep course in the same way as a larger fin, and it will be more difficult for him to maintain stability in choppy waters.

Fin Characteristics

For touring (that is, traveling on water over long distances), fins with a larger area are used, which allows the board to stay on course and not lose speed. It should be noted right away that maneuverability with such a fin is somewhat complicated.

For cruising riders, riders choose fins that are similar in shape to touring fins, but thinner. This way you can achieve less resistance and the surfboard will go much faster without deviating from the set course.

Maneuverability in this case lies entirely on the shoulders of the rider: the more he trains, the better his board control and the ability to turn it around quickly in any conditions.

Remember: the larger the fin, the better the stability on the course, but the greater the resistance and vice versa.

Of the minuses, thin twin paddle is fragile, therefore, not suitable for other directions of SUP boarding, where there is a chance of catching and breaking the flippers.

Weed fins

Unifiber recently introduced a series of Weed fins for those who regularly find themselves on glanders where there is a lot of algae in swampy areas.

The fin is designed in such a way that nothing is wound around it.

By the way, the short elastic is not only suitable for use in shallow waters, but will also be indispensable for surfing in the coastal line with a rocky bottom, as well as for beginners who often fall off the surfboard and can get injured on a regular plastic fin.

When it comes to surfing, the choice of fins is huge. FCS and Future Fins mounts are also added here, and under them, respectively, a wide selection of fin.

Riders pay attention to size, curvature, depth … The seemingly insignificant characteristic can greatly affect how you will feel on the surfboard during maneuvers.

What to choose


If you just got on the glanders or decided for yourself that an inflatable surfboard is enough for you for leisurely walks in local waters, then the supplied fin will be enough for you.

We also recommend that you stock up on one more of the same in advance, in case the first one disappears somewhere. Believe me, it happens!

And without a paddle you will not go far, and the time spent looking for a new one could be spent profitably on the water.

The owners of hard glans should be more careful with their fin choice and decide what exactly they want from their surfboard.

Again, depending on your water activities, you may well have more than one type of fins, which is the best solution.



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