Why is G10 Still The Best Material For Windsurfing Fins?

By Chris Freeman 3 years ago

Best blend of performance, durability and overall cost

We have been making G10 windsurfing fins for a decade, long before that we decided to use G10 fins in our own boards after extensively testing a vast selection of fins and materials. Both Chris and Tom are fin addicts and have been experimenting since early in the sport’s history. So, given that so much has changed in windsurfing, why has G10 remained the best choice for fins, surely there is some new fancy material available?

You will have seen a lot of talk about other materials, from carbon to plastic, each with their own supposed advantages. Despite these other options, it is our strong belief that for the overwhelming majority of windsurfers, G10 fins provide the right mix of performance and durability that windsurfers at all levels from getting into the foot-straps to competing nationally and internationally, and you can get this at a reasonable price.

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Let’s start by explaining what G10 actually is.

G-10 is a high-pressure fiberglass laminate, a type of composite material. It is created by stacking multiple layers of glass cloth, soaked in epoxy resin, and by compressing the resulting material under heat until the epoxy cures.

It is produced in flat sheets which make it ideal for CNC manufacturing a consistently high quality product. G-10 is the toughest of the glass fiber resin laminates making it ideal for windsurfing fins.

G-10 is favored for its high strength and stable composition. It was first used for printed circuit boards, and its designation, G-10, comes from a National Electrical Manufacturers Association standard for this purpose.

G-10 is produced in many colors and is used to make handles for knives, grips for firearms and windsurfing fins.

As with any material there are different quality grades, we choose to use a very high quality supply of custom made black G10, this adds about 15% to our production costs.

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So how does this all relate to your windsurfing fins and how does the use of G10 improve your level of windsurfing enjoyment?

It just so happens that the properties of G10; strength, durability, machinability to list a few, are well suited to windsurf fins. When designing any product, you have to adhere to a number of design parameters in a way which best utilizes the characteristics of the materials which you are using. Over the past 10 years, we have become experts at designing G10 windsurfing fins.

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What about carbon windsurfing fins?

Over the years there has been movement for racers, even some recreational blasters to ask for custom carbon slalom fins, citing enhanced flex control, higher speeds and more. There are some performance benefits for elite professionals offered by hand crafted carbon layups. It is our view that the benefits of carbon are far outweighed by the negatives not only for the rider but also for the sport of windsurfing.

Carbon slalom fins used at the top of the sport are expensive and prone to damage. These fins are made by a select group of skilled individuals to a very high standard and are not just fins ‘made in carbon’. In reality no two fins are the same because they are handmade.

Real carbon slalom fins by their very nature are labors of love and are expensive to produce, we looked at it for quite some time. We found that they worked well, but we decided that selling $500+ fins which can easily be destroyed on the first session is not in the best interest of most windsurfers and the sport – which is expensive enough already.

For those on wave, freeride and freewave boards, the durability, excellent performance and reasonable cost of G10 makes sense. We want to keep windsurfing fun and it is not fun if you are worried about damaging your gear, and fins by their very nature are at risk of hitting submerged objects.

It is hard to accurately prototype carbon fins, for that reason companies end up making prototypes in G10 and then making the production runs in carbon. But what works in one construction material doesn’t necessarily work in another with different properties.

In contrast our G10 production fins are identical to the final prototypes, made in the same way and in a repeatable manner on the same CNC machines. When we test and put our fins into production, you get the exact same fins as we are using, this cannot be said for carbon fins which are prototyped in G10. This means when a sailor tells me what fin they are using from our range, I will know exactly how that fin(s) ride and I can be confident on my recommendations.

As a windsurfer, I know you will enjoy far more benefits from having two G10 fins of different sizes than one made in carbon – the price difference can allow you to do this. From years of advising people on the fins to use, I know that correct sizing is far more important than the material a fin is made in.

G10 vs Carbon: G10 is heavier than carbon but results in a more durable, more consistent production and better value for money over carbon fins. 


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What about plastic fins?

The best thing going for plastic fins is cost, once you have the mold set up then the cost of making each fin is very small. As cited as an advantage for G10 fins, a lower cost means that it is more likely that as a customer you can have a range of fins and hence be able to size them accordingly (very important – see size charts). A correctly sized plastic fin is going to be better than a wrongly sized carbon or G10 fin.

The major downside that we see with plastic fins (even ones which are stiffer) is that they are more flexible than we consider to be optimal. This is especially true for heavier windsurfers or people who sail with more power. If you look at the demographics (paying customers) in our sport, very few of us are the wiry 18yr old’s (we once were, but no longer), and most of us don’t windsurf in the conditions we would love to. It is taking these factors into account that makes us use G10 for the fins which we make for you to use.

In windsurfing, everything becomes easier with speed, a quality fin, often with a thinner foil (possible with G10, not possible in plastic and too fragile in carbon) is going to get you into and out of trouble faster. A sluggish more flexible plastic fin lacks the drive you want and hence you need to compensate with a bigger and less efficient fin set up.

Flex is important, many people hold a G10 fin in their hands and try to bend it, that is not a realistic test, put the fin in the water and exert the real force that comes from sailing and carving hard and you will see it flex. If you can flex something with your hands (which sometimes cant even open a stuck lid on a jar) then you know it’s too flexible to work in the ocean.

Flex can be controlled by materials and design, we build flex into our G10 fins where we want it, not where the material dictates. The right degree of flex helps to add control in choppy and overpowered conditions. Too much flex and you will lack speed and have an unpredictable ride.

There is a lot of talk about the wave performance of a more flexible fin, but in my opinion of watching and sailing with the best in the world that simply doesn’t hold true. If you look at all of the recent winners of the Aloha Classic, they were all using G10 fins. What you are looking for as a wave sailor is a board that holds its line to take advantage of its rocker to carve; if the fins loses grip by over flexing then the board will have to re-adjust and this impacts your performance on the wave.

If you want a looser feeling fin set up, try smaller and more efficient fins.

As windsurfers, almost all of us search for more performance from our gear, even when improving our technique is probably the better bet – watch some old videos, see the gear, see how much they were ripping on gear that you wouldn’t buy off eBay now!

I know from personal experience that changing your fins is the easiest and cheapest way to improve the performance of your board. So, when we all spend thousands on boards, sails, masts, booms and more, why do we feel that we should choose fins because they are cheap, I know that there is a balance between cost and performance (as we have talked about when comparing carbon vs G10) but it doesn’t make sense to me to completely prioritize price over performance.

Given the huge numbers of people taking part and competing in surfing (which influences windsurfing) it is perhaps illuminating to be aware that the trend in surfing is moving in the other direction and putting more emphasis on performance fins.

G10 vs Plastic: Price is a key factor which makes plastic fins attractive, but at what cost to your windsurfing performance and long-term development? Being able to correctly size your fins on a budget is also great and right for some, but G10 fins are not that expensive compared to the price of all the other gear so the difference is a tank of petrol and well worth it.


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In Summary: What are the main pros and cons of G10 fins?

Black Project cares deeply about people’s enjoyment of the sport of windsurfing. We strive to develop and supply products which help maximize performance, while making sense in terms of production. With this in mind we stand firm in the belief that given a wide range of considerations, G10 is the best material for windsurfing fins.

Pros of G10

  • Extremely durable and long fin life.
  • Precision CNC manufacturing and consistent production.
  • Good flex characteristics, when designed correctly.
  • Can be machined to thin specifications.
  • Can be easily sanded to fix minor damage.
  • Reasonable cost of production.


Cons of G10

  • High cost of manufacturing.
  • Limited capacity of CNC machinery.
  • Stiffness if poorly designed or produced.
  • Heavier than carbon and plastic.
  • Not the cheapest to buy.

Fin Construction Comparison

CriteriaG10RTM CarbonCustom CarbonPlastic
Production ConsistencyExcellentGoodExcellentExcellent
Wave useExcellentGoodN/AGood
Freeride useExcellentGoodN/AFair
Racing useGoodFairExcellentPoor
Value for moneyExcellentGoodPoorExcellent

REMEMBER: Upgrading your fins is the easiest and cheapest way to improve the performance of your board.

Need help choosing a fin?


More Windsurf Fin Resources

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Wave fin size chart 

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Freeride fin size chart 

Slalom & Racing fin size chart


Images: Nick Jones & Black Project

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