Both my Fanatic falcon LW and my JP SLW state in their catalogue that they come with carbon fins but they don't look like say a select S Max carbon fin where all you can see is carbon. The falcon one looks like it's painted so can't really tell but the JP is not and I can see fiberglass cloth on it when I turn it sideways under light. Do they only have to have some carbon in there to call it a carbon fin?

Someone was pimping the Fanatic boards on a forum saying they came with full on carbon fins. They dont, they come with Choco Black Pearl fins. I emailed Choco and got a swift response from Daniel Aeberli no less. He said they were 75% carbon iirc.
My Starboard Drake carbon fins do have layers of carbon in them, but you can also see glass cloth once the paint has worn off. I guess they are 50% carbon judging by the price, although thats no certain indicator. You wont get a 100% carbon fin for the price of a G10 + 20%.

Select had an article which said "If we compare molded carbon fins, on an S1 Pro, we have 65% carbon, it goes to 80% on a V-Max 4 and 100% on a Rhino Pro. "
www.planchemag.fr/2020/04/made-in-france-select/

Shame they dont tell you the carbon content of the fins (and booms), like they do with masts.

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PhilUK said..
Someone was pimping the Fanatic boards on a forum saying they came with full on carbon fins. They dont, they come with Choco Black Pearl fins. I emailed Choco and got a swift response from Daniel Aeberli no less. He said they were 75% carbon iirc.
My Starboard Drake carbon fins do have layers of carbon in them, but you can also see glass cloth once the paint has worn off. I guess they are 50% carbon judging by the price, although thats no certain indicator. You wont get a 100% carbon fin for the price of a G10 + 20%.

Select had an article which said "If we compare molded carbon fins, on an S1 Pro, we have 65% carbon, it goes to 80% on a V-Max 4 and 100% on a Rhino Pro. "
www.planchemag.fr/2020/04/made-in-france-select/

Shame they dont tell you the carbon content of the fins (and booms), like they do with masts.

Hmmm interesting I've always taken it for granted that carbon fin means 100% carbon except for the resins. Select have melded the S1 pro and the V Max 4 into a new fin called S Max, I've been thinking about getting one I wonder what % they are

Another cost mentioned in the Select article is the amount of time it takes to make a fin.

Finally, it takes between 2:50 hours to assemble the patch work of the 70 carbon parts to make a Rhino, 1:50 for the 45 parts of the s1 pro and the vmax 4 and about fifty minutes of machining for a model in G10 progression .

A fin that was made completely out of carbon would likely be too stiff. The exact layup with a custom carbon fin is the secret sauce. This is one of the things that separates a carbon fin from a solid material like g10, that is the same all the way through.
If you snap one which does happen with proto types. You will see what's inside.
There are also RTM carbon fins, that can be more readily mass produced. RTM stands for resin transfer molding, the resin is sucked into the mold after the fibre had already been placed in the mold. Some fins use prepreg heated in an oven. Etc etc.
There is lot of work in a hand made carbon fin.

Don't overthink the carbon content. Most top end hand-made carbon slalom fins have foam/wood/fibreglass/filler cores because a sold carbon fin (think like a foil mast) would be waaaay too stiff.

You really need to know from the manufacturer what's inside them (the heavier the fin, usually the more fibreglass in them) as visually it's hard to tell because you can put layers of jazzy looking cloth on the outside to make them look nice or put paint and graphics in the gel coat to hide whats in them.

The difference between a hand-made carbon fin (Z-fin, CA, Kashy etc etc) is they hand finish them by eye which takes hours and gives a bit of difference between each fin but they are usually perfect; whereas the mass produced carbon fins stick to a simpler to reproduce layup and don't finish them so they can have miniscule bumps in them (or they usually have a much thicker trailing edge so it doesn't crack off when you pull the fin out of the mould) that you'll notice when you spinout in a gybe. That all being said... the longer the fin, the more this is noticeable. +40cm fins you'll benefit from good carbon fins... tiny 30cm high wind fins you can still use G10 and be happy.

Been back sailing just over a year - gathered quite a collection of fins already, some awesome, some good, some bad, one "carbon" that should never have been made. A "carbon" fin doesn't mean much, the good ones are great but the ****e ones are still ****e. In terms of what is being sold with boards I would suggest it's just a marketing thing to say hey look 'carbon' fin, and yes any amount of 'carbon 'qualifies a fin to be 'carbon'

I was just texting my mate over this. He makes fins for a few of the pwa riders. He uses about 90% carbon. But for his foils it's 100%.
From what I understand you need a little bit of flex to get some lift which equals some resistance and avoids spin out when you start putting pressure on the fin. But, hey open to criticism on that.
And up until about an hour ago I thought the fins were 100% and the arrangement of fibres is what made the flex.

I think it's key to remember that 'carbon' is a buzzword that gets us going, and we can forget what it actually means.

As a material, carbon is expensive but it's value is in its high tensile strength. You can make something lighter and stiffer by using carbon and, with the right layup, you can also get a better reflex response.
But not all fins need to be stiff - like with wave board fins where we like flex in the fin on the wave face.

Carbon is a useful component in longer fins, such as we use for slalom boards. Fins over 40cms long probably need to be carbon if they are to be stiff enough and strong enough not to break under load - whilst still being thin enough to be fast.

When we say something is 80% carbon that refers to the cloth materials used in the layup, but not the resin content.
(And it's often the resin and the filler used that makes up a lot of the weight. )

Carbon is more difficult to cut and can be harder to work with, and for a while it was hard to get hold of, so it cost even more.
So when a manufacturer boasts of selling a 'carbon' board or fin they are letting you know that they didn't skimp on costs by using the cheapest materials. But they can still legitimately use the word even where the actual carbon content is quite low.

Basher, maybe stick to board reviews

S-glass has a higher tensile strength than carbon, as does basalt and kevlar.
Carbon's advantages lie in stiffness and strength to weight ratio.

So you were right about lighter and stiffer, but not tensile strength. That's where u lost me.... but I read on anyway and discovered the jewel:
"Carbon is more difficult to cut and can be harder to work with..." and its neither.

Rot.

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Mark _australia said..
Basher, maybe stick to board reviews

S-glass has a higher tensile strength than carbon, as does basalt and kevlar.
Carbon's advantages lie in stiffness and strength to weight ratio.

So you were right about lighter and stiffer, but not tensile strength. That's where u lost me.... but I read on anyway and discovered the jewel:
"Carbon is more difficult to cut and can be harder to work with..." and its neither.

Rot.

Yes to stiffness and strength to weight ratio. That's what I said.
Do we have fins made from S Glass or Kevlar?

Sounds like I need some new scissors.

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Basher said..

Mark _australia said..
Basher, maybe stick to board reviews

S-glass has a higher tensile strength than carbon, as does basalt and kevlar.
Carbon's advantages lie in stiffness and strength to weight ratio.

So you were right about lighter and stiffer, but not tensile strength. That's where u lost me.... but I read on anyway and discovered the jewel:
"Carbon is more difficult to cut and can be harder to work with..." and its neither.

Rot.

Yes to stiffness and strength to weight ratio. That's what I said.
Do we have fins made from S Glass or Kevlar?

Sounds like I need some new scissors.

You said "As a material, carbon is expensive but it's value is in its high tensile strength."
That's incorrect, the tensile strength is comparable to S-glass.
Elongation at break is way better for glass too. (bends lot further before breaking)

Then you mention stiffness - yes. Stiff - and strong for it's weight, yes. But it does not have exceptional tensile strength at all.
You fell for the 'carbon is strong' thing. Its not. All are for different applications.

Carbon cuts just the same as glass with scissors. Kevlar is a nightmare and if you get 10 linear metres out of normal dressmaking scissors you're doing well. If you can't cut carbon the same as glass with normal scissors, something is wrong.

And yeah we do make fins out of S-glass last time I looked, its called G10 / G11.


Nice little chart for you, line 3 if you wish.

www.colan.com.au/compositereinforcement/resources/fibre-information/fibre-comparison-charts/

Luckily, people can still read what I wrote.
Not sure why I am being attacked when everything I said about fins (on topic) was valid.

Carbon IS known for its tensile strength, being stronger than steel.
it is true that it can be difficult to work with, and sometimes dangerous - and you can google that.
It is also true that I didn't mention kevlar, but I didn't mention tea bags either.

We tend to make slalom fins out of carbon to get the strength and stiffness plus flex needed for such a long fin. You should also get a lighter fin, for the given fin area. I understand that carbon works well with an epoxy lay up because the carbon works well in tension and the epoxy works well in compression.

We tend to make fins in G10 where hardness and durability is a key selling point. If any readers here are using long G10 fins for slalom racing then perhaps let us know.
The G10 fins I have in my wave boards are MUFC ones which tend to be a bit stiff - but they wear well on sandy beaches!

MFC make a range of polyester/glass fins to be more flexible for wave boards - but they chip easily.

And K4 make injection-moulded plastic fins that also have controlled flex - and the simplicity of manufacture makes them economic to buy.

Anyway, gotta go. It's lunchtime here and the wind has just kicked in.

Except it is NOT known for its tensile strength at all. To refute that is not an attack- you said its value lies in its tensile strength and that ain't true.

And it is NOT hard to cut.

That's not an attack mate.

So you regurgitated all that is already known about fins (congrats) and then added some stuff to try and sound all tech - which was wrong. Its tensile strength is NOT amazing, its the same as S-glass.
Its NOT hard to cut, maybe your wrist or grip strength is diminished.

Like I said yes its stiff, yes it "stronger than steel" for its weight but "tensile strength" is only one part of a very complex set of qualities for any material in any given application. Tensile strength of carbon is not high. It is the same as s-glass - pure and simple fact. Go look at the properties in the table (link) I posted.
BTW I never said that means we should use glass fins for slalom racing.

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Mark _australia said..
"Carbon is more difficult to cut and can be harder to work with..." and its neither.

Rot.

I think there a mix up with kevlar here

^^^ me too

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decrepit said..

Mark _australia said..
"Carbon is more difficult to cut and can be harder to work with..." and its neither.

Rot.

I think there a mix up with kevlar here

When I was a younger Subsonic, I went and bought some Kevlar to fix up the back end of a cherub centreboard case that I managed to smash to smithereens whilst rock fishing.

Hadn't played with composites before that, I spent 20 odd minutes wondering where the shop attendant had got to after I asked for what I wanted, expecting her back in 5 min. Wasn't till I got home and tried to cut it with mums best scissors that I solved the mystery. I can only begin to imagine how much sharper the shop attendants scissors were compared to mums.

My fingers were so sore.

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mob dog said..

Hmmm interesting I've always taken it for granted that carbon fin means 100% carbon except for the resins. Select have melded the S1 pro and the V Max 4 into a new fin called S Max, I've been thinking about getting one I wonder what % they are

There is probably more carbon in the Select than the Drake DW and Slalom-8 fins I have.
The V Max had more rake than the S1 from what I remember.
The new S-Max looks similar in rake to the S1. Although 1 brochure shot of 1 fin doesnt mean all fins lengths have the same rake.
I have a S1 in 35cm, and find it a bit too upright on my Exocet, which has a long flat and low rocker overall. Even the more upright (than the DW) 38cm Drake slalom-8 has more rake. So I bought a DW 36cm.

I was going to buy a Drake Slalom-8 46cm for my largest board, despite that being slightly less easy to gybe. But they had sold out of that so I got the DW, which is fine to gybe. The more upright Slalom-8 requires more even pressure on the rail.

But for a Fanatic LW or JP SLW, a slightly more upright fin being slightly less forgiving in the gybe wont be the biggest factor in gybing. That will be a big board and presumably big sail, lighter winds and less speed into the gybe.

btw... I have one select 44 fin V-MAX for my isonic 127 and I do like it

I have S-MAX 36 and 39 for my simmer free move 116l and I like it also :D

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Mark _australia said..

Basher said..

Mark _australia said..
Basher, maybe stick to board reviews

S-glass has a higher tensile strength than carbon, as does basalt and kevlar.
Carbon's advantages lie in stiffness and strength to weight ratio.

So you were right about lighter and stiffer, but not tensile strength. That's where u lost me.... but I read on anyway and discovered the jewel:
"Carbon is more difficult to cut and can be harder to work with..." and its neither.

Rot.

Yes to stiffness and strength to weight ratio. That's what I said.
Do we have fins made from S Glass or Kevlar?

Sounds like I need some new scissors.

You said "As a material, carbon is expensive but it's value is in its high tensile strength."
That's incorrect, the tensile strength is comparable to S-glass.
Elongation at break is way better for glass too. (bends lot further before breaking)

Then you mention stiffness - yes. Stiff - and strong for it's weight, yes. But it does not have exceptional tensile strength at all.
You fell for the 'carbon is strong' thing. Its not. All are for different applications.

Carbon cuts just the same as glass with scissors. Kevlar is a nightmare and if you get 10 linear metres out of normal dressmaking scissors you're doing well. If you can't cut carbon the same as glass with normal scissors, something is wrong.

And yeah we do make fins out of S-glass last time I looked, its called G10 / G11.


Nice little chart for you, line 3 if you wish.

www.colan.com.au/compositereinforcement/resources/fibre-information/fibre-comparison-charts/

I had a bit of experience cutting kevlar. Found a good pair of dressmaking scissors which cut kevlar really well. However, after moving on to glass and carbon, I found that I couldn't go back and cut kevlar. "She" asked me how come her good scissors were blunt and I just pleaded ignorance.
Found out later that you have to stick with one material for each set, if you're including kevlar. 2 sets of good scissors, nup!

I was curious about Kevlar, but I don't want to play with it now .
Where would I use it on a board build , nose guard , on the top ridges of the rails next to a sunken mast track ? The way I read it , Kevlar is good for high speed impact and abrasion resistance . Not good at stiffening such as under heels ?

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Imax1 said..
I was curious about Kevlar, but I don't want to play with it now .
Where would I use it on a board build , nose guard , on the top ridges of the rails next to a sunken mast track ? The way I read it , Kevlar is good for high speed impact and abrasion resistance . Not good at stiffening such as under heels ?

That why it used in hybrid weave, e.g. carbon/kevlar weave. My freestyle board has a wood deck, laminated with carbon/kevlar weave, Very strong and reasonably stiff. There are other substitutes for kevlar in this application, innegra for example.

^^^ +1. gold standard construction.
Imax its not that bad just buy new dressmaking scissors, the ones with tiny serration on lower blade
$30 added to cost of board is not too bad
Just need to cut very accurately around rail 'seam' with the bottom to avoid sanding it.

+1^^^
Yes sanding is probably a bigger problem than cutting. If you get the kevlar well underneath the layup. It's a great help in the impact areas.

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Select 55cm, very stiff, slightly fatter foil
Drake 54cm, quite flexy

The drake feels like you have more to push against when pumping onto the plane but does get a hanfull fairly quickly at speed

The select spins out easy at lower speeds and doesn't give you much to push against but is way nicer when powered up and blasting,

I'd be interested to see if Slowy has anything to say regarding this....

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decrepit said..

Mark _australia said..
"Carbon is more difficult to cut and can be harder to work with..." and its neither.

Rot.

I think there a mix up with kevlar here

I tend to cut Kevlar with a cheap pair of scissors just tape down masking tape on top of the cut line and cut through both.

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ADinis said..
btw... I have one select 44 fin V-MAX for my isonic 127 and I do like it

I have S-MAX 36 and 39 for my simmer free move 116l and I like it also :D

I've rebased a V max fin and looking at the cross section I would say 20% carbon, the wear on the tip of the fin exposes the glass underlay.

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ADinis said..


I have S-MAX 36 and 39 for my simmer free move 116l and I like it also :D

Someone actually has the fin in question.
Is the rake of the 36 & 39 the same as the one the show on their website?
www.select-hydrofoils.com/en/shop/windsurf/s-max/

eg the trailing edge at the tip on my FHot is behind the end of the tuttle box head, whereas with the Drake it sits above the end of the tuttle box head. How dos the S-Mx compare?

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racerX said..

There are other substitutes for kevlar in this application, innegra for example.

Innegra and Kevlar are not good comparisons. Innegra is like an elastic noodle, kevlar is relatively stiff - Certainly the K49 composite version is. Both are awful in compression.

I personally would avoid innegra for all windsurf applications. It has a huge elongation on breaking, something like 20%. So it is super elastic compared to anything else in your boards. It also provide very little in terms of stiffness (other than taking up space like a sandwich might). I have heard of surfboard makers in the UK using it between glass layers like a micro sandwich, but I struggle to see its benefit over another layer of glass, certainly not when compared to other fibres out there like Dyneema. Here is a nice video of Innegra being used in a laminate:

Have a look at easy Composites video on the materials:

I have found that Kevlar needs to be hidden in the layup, preferably under lots of glass, so you never hit it when sanding. Kevlar is good under the sandwich and especially under the sandwich under the heals, where its low density means you can put more fibres in for the same fabric weight of glass for example.

Kevlar does come with down sides though - it doesn't like to stick very well to anything, it costs the earth and it is absorbent. I actually think under your sandwich and under your heals you would be better off with carbon.

Still trying to understand max tensile strength being relevant when it comes to fins. Are fins really under that much force? Foils I could understand, but not fins. Unless they are mega big ones perhaps.

Is Kevlar ever used in Fins?