Fin systems - adjustable

ShaneK's picture
ShaneK started the topic in Saturday, 12 Jun 2021 at 9:29pm

I'm interested in fin systems that allow adjustment of fin position. I have some boards with the old PowerBase system that have adjustable back slots. This is useful for quads as you can move the back fins forward to get a more twin fin feel, or back for more control.

I saw an old comment on another forum from Nick Carroll (link to original below):

"I suspect pretty much any board will go better if the frontside rail fin is a quarter of an inch further forward than the backside rail fin. Every single board I've been able to do this on has gone way better. But if you're not using Surffinz or a similar box in which you can shift fins up and down, you can't try it."

Does anyone have experience of this with Surfinzs boxes or another system?

My guess is that these kinds of adjustments would be far more important to board performance than any of the variations of fin design.

https://forum.realsurf.com/forums/viewtopic.php?t=27450

birdfood's picture
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birdfood Sunday, 13 Jun 2021 at 9:27am

I don't think they're in business anymore. 4wfs is another I would have liked to try.

I've been doing a bit of research on this lately and I've arrived at:

It makes business sense that you can't adjust your fins with FCS2 or Futures boxes, if you want to change how your board rides you need to buy another set of fins.

You could look at getting 6 inch long board boxes put in your board instead, but you'd need to get custom made thruster/quad fins.

Or go with zillions of FCS1 plugs https://www.bourtonshapes.com/the-little-zapper/

Or maybe the ausfinco boxes if you again got custom made fins that were a single tab and shorter than the box slot https://www.ausfinco.com/product-page/fin-solution-fin-plug

If anyone knows of any other system that just works I'd love to know!

udo's picture
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udo Sunday, 13 Jun 2021 at 9:49am

https://www.4wfs.com/contact-us/
https://triggerbrothers.com.au/surfinz-fin-plug-updating/

https://www.wasabisurf.com/ These are a bit pricey - getting some 3D printed in Aust soon / unsure of cost but should be much cheaper than Wasabi

ShaneK's picture
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ShaneK Sunday, 13 Jun 2021 at 12:00pm

Totally agree Birdfood with the comment about 'business sense'. If we could do more with one set of fins, it's unlikely that we would buy so many different sets. As surfers, we have ended up with a worse system because of this.

Still, I reckon there is potential there for a move away from this in the future. Imagine if on every stock board you could adjust your forward fin position slightly depending on if you were natural or goofy...

It's kind of crazy that boards are designed so symmetrically, yet we don't surf them symmetrically because we are not symmetrical.

Thanks Udo, I hadn't seen these systems. The 4WFS system looks interesting - I wonder if too much choice becomes overwhelming...interested in reports.

brutus's picture
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brutus Sunday, 13 Jun 2021 at 12:09pm

been using adjustable fins since the Redex era , now I use Surfinz on my own boards as there is close to 3/8" of backward/forward movement.
Moving just your backfin a 1/4" forward , loosens the board to nearly too loose.....as Nick said your forehand fins can be 1/4" further forward than the backside fin position ....bottom turns have a much longer radius than the top turn....so that's where asymetrics comes in......
If you want to stiffen the board, keep back fin where it is and increase the distance/spread between the back and side fins....so much to play with I often do adjustments in the water just to see from wave to wave positives and negatives.
The whole fin system industry is geared towards selling punters lots of fins with marketing spiels , that make you think you need their latest greatest new fin teck design , when in reality the best fins are all fibre glass.....

The fact that not even pros move their fins , because their shapers just don't have the knowledge to use fin positions to fine tune their boards......so the market does not want adjustable boxes as they make their money out of selling lots of fin sets!

groundswell's picture
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groundswell Sunday, 13 Jun 2021 at 12:11pm

Whenever i get flat broke, the easiest way to get some coin is sell a few sets of fins on gumtree for $120 each or something. Sold within a few hours.

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seaslug Sunday, 13 Jun 2021 at 12:15pm

I have some old FCS1 fins that I no longer use, wonder if they would sell groundswell

udo's picture
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udo Sunday, 13 Jun 2021 at 12:17pm

They will sell no probs on Gumtree or Facey marketplace or on here

birdfood's picture
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birdfood Sunday, 13 Jun 2021 at 12:22pm

Are surfinz still in business or have you got a stockpile brutus? That triggerbrothers website is the first place I've seen them in stock Udo.

I was thinking the other day while surfing that getting your own wasabi style inserts made would mean you could make different inserts with different cant angle and potentially design in the ability to slide your fins forward and back a little. I'd be keen to hear how you go with them Udo.

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udo Sunday, 13 Jun 2021 at 12:25pm
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udo Sunday, 13 Jun 2021 at 12:46pm

Birdy- the chap at Ballina i spoke with re the FCS into Futures Adaptor already offers a Free File Download to Print an adaptor for FCS into a long single fin box
And will happily do the scanning or whatever to make the File for the Fcs to Futures adaptor for Free
what a fucking legend eh...i offered to pay him for his time..but no i will do it for Free im just very busy at the moment but its called 'Sharing the Love' he says..
What a Champ !
Mitchell Ray and Grant Miller also use the Surfinz boxes

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udo Sunday, 13 Jun 2021 at 1:09pm
ShaneK's picture
ShaneK's picture
ShaneK Sunday, 13 Jun 2021 at 8:30pm

Thanks for input everyone. Great to know there are some shapers who are looking at this! Gives me increased confidence to explore this in the future with new shapes.

udo's picture
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udo Sunday, 13 Jun 2021 at 11:09pm
sanded's picture
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sanded Monday, 14 Jun 2021 at 12:38am

Another Fin system Gearbox 2
Gearbox has a slight adjustment for FCS1 fins and their own Hanalei fins
http://gearbox.surf/
https://www.sanded.com.au/collections/surfboard-fin-system/products/gear...
We have been approached to be distributor for Australia for a new system coming out later in the year, the boxes will fit every fin system fin except Futures - saw the prototype it looks good and easy install- should be out before summer

brutus's picture
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brutus Monday, 14 Jun 2021 at 10:25am

birdfood wrote: Are surfinz still in business or have you got a stockpile brutus? That triggerbrothers website is the first place I've seen them in stock Udo.

I was thinking the other day while surfing that getting your own wasabi style inserts made would mean you could make different inserts with different cant angle and potentially design in the ability to slide your fins forward and back a little. I'd be keen to hear how you go with them Udo.

Bird , yeah I have a stockpile of them , as I personally love them , as I have been able to work out better fin positions than most by trial and error.....and you can change the performance of your board by probably 20% + just by making small moves......but you have to want to experiment , 99% of the market just want to surf....even to the point where surfers are going back to glass ons , which shows to me a regressive mentality or" rough enough , good enough!"
Surfboard design and surf hardware, are still in the Neanderthal stages of evolution.....just look at what the Pro's ride!

groundswell's picture
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groundswell Monday, 14 Jun 2021 at 12:05pm

Fish are best with glass ons untill somebody makes fin slots at 7-10 inches long

udo's picture
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udo Monday, 14 Jun 2021 at 12:48pm

If that was the case Machado, Banks, Vanstraalen and every one else would have pushed for bigger boxes years ago .
All seem happy with FCS or Futures boxes ?
FCS CI keel has a 163mm - 6.4 inch base or wetfins have a set with a 175mm -6.875 inch base.

groundswell's picture
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groundswell Monday, 14 Jun 2021 at 12:50pm

Thats because most people surf fish in small crappy surf. when surfing double overhead speedies glass ins go better.Fish are designed for lined up down the line pits and need strength in the glassing. ive seen a lot of fin boxes ripped out of the glass because of bottom turn pressure with large keels with a cutout at the rear.

brutus's picture
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brutus Monday, 14 Jun 2021 at 1:34pm

groundswell wrote: Thats because most people surf fish in small crappy surf. when surfing double overhead speedies glass ins go better.Fish are designed for lined up down the line pits and need strength in the glassing. ive seen a lot of fin boxes ripped out of the glass because of bottom turn pressure with large keels with a cutout at the rear.

If you are ripping finboxes out doing turns, it means the boxes are not correctly installed....the futures are by far the strongest , but their Keels do have that cut out at the back and after surfing C-drives with long bases....the only keels I can use are the old twin tab ones and surfinz boxes. The surfinz boxes are weak and need to be installed with milled fibreglass and an extra layer of cloth over the actual box!

udo's picture
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udo Monday, 14 Jun 2021 at 1:52pm

Brutus have you tried Gearbox boxes ?
do you know why some brands of dual tab keels also have the rear cutaway ?

Groundy can you tell Torren Martyn to go a bit harder...Not getting any box damage even at below sea level 12ft Plus Dredging Nias

philosurphizingkerching's picture
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philosurphizing... Monday, 14 Jun 2021 at 2:26pm

I am currently building wooden Asymmetrical number 3, each build incorporating more of the asymmetrical steps.

For this build I want to experiment with being able to move the heelside/ cutback fin back, but keep the fin box the same distance from the tail as the previous build which was a 6'' longer board at 7', this build is 6' 6''.

So my plan is to modify the finbox by adding a third grubscrew by drilling and tapping a 3/16'' whitworth thread into the middle plug of the slotted finbox .

Then by cutting 22mm off the rear of the fin tab (see photo, blue tape will be the tab size)which is currently 74mm long I will be able to move the fin back 22mm and still be able to secure it with 2 grub screws.

You could also do the opposite of this by making a second fin and cutting 22mm off the front of the tab which then gives you 3 fin positions to try with 44mm of variation.
IMG-2394
upload img

velocityjohnno's picture
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velocityjohnno Monday, 14 Jun 2021 at 2:56pm

Great thread everyone, there are a lot of fin plug & box variations out there. 4wfs looks pretty rad in how you can customise them. Thankyou again to brutus for sharing your experimenting & results. Surfinz look the way to go for the ability to adjust fore and aft.

udo's picture
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udo Monday, 14 Jun 2021 at 3:04pm

Gearbox also have a little Fore and Aft Adjustment
And can get a tad more by trimming fin tabs

velocityjohnno's picture
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velocityjohnno Monday, 14 Jun 2021 at 3:34pm

Thanks Udo, if surfinz not available I see Sanded has the gearbox and all it's setup gear - that would be the next best. Also, it advertises itself as light, not going into the shape much and that's what I like about FCS fusion. If I wanted more fore/aft movement, I could machine my own fin plug/box out of something solid without too much trouble. Now you've all got me thinking!

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udo Monday, 14 Jun 2021 at 3:40pm

You have access to Machining equipment ... Mill etc ?

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velocityjohnno Monday, 14 Jun 2021 at 4:02pm

Yep, had to do something during corona lockdown down here, I went all techhy. It's been the funnest thing ever, built the whole thing myself. When I was young in 90s I built a mechanical rocker machine for my boards (pre internet! had to wing the lot of it as I couldn't even find a picture of one to base it off out on the West coast - it ended up looking a lot like Pat Morgan's one in the surfcoast surf museum, ha) and so mills make great sense to me. After I got sick about 5 years ago, I couldn't shape boards for a while so I learned CAD instead. It's been so fun, and kept me on track during the harder times.

For a finplug/box, Cad design & CNC code generation would be super easy, and I'd probably make it to be easily routed in with tools on hand, not worrying about weight etc too much. It's something where one could go pretty custom, putting in cant angles, adjusting up & down, even doing weird things with close separate plugs etc.

udo's picture
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udo Monday, 14 Jun 2021 at 4:19pm

Got something for you to think about - FCS fin to Futures box adaptor
Wasabi do one but a tad pricey with Exchange rate and shipping from USA
Have someone organised to 3D print but i think poss cost is over $30 per box
your thoughts on machining from a solid blank / infill piece - Time and Cost?
https://www.wasabisurf.com/

velocityjohnno's picture
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velocityjohnno Monday, 14 Jun 2021 at 4:31pm

Hi Udo I had a look at these before as I went over the link. You could do it from a piece of perspex (will this snap? Is solid ABS better? Would have to test) as a double sided machining job, and carve it out of a solid block with tabs attaching it, a bit like the parts of a model aeroplane. For what I do, it would take a bit of machining time, especially if you did a rough raster to remove material, then finished it up to be nice and smooth with another run on both sides. That particular shape might need an extra axis, or some finishing work but I think I could run it without this looking at the shape. Overall cost wouldn't be too high, it's just the time involved. For bulk pieces at low $$ cost, maybe machine out a good injection mold but that's when the tech gets beyond me (for now!) For not having to go through all that time, maybe $30 is still a little steep ha!

I can only compare it with buying the FCS conversion for back finbox into dual tab fin, that was similarly priced? I still have the one I bought years ago.

Now 3d printing one (I have a cheap 3d printer) would be a relatively quick job, yes filament costs but you will get quite a few out for the $60 or so retail cost of filament. Make sure your printer can do ABS - my old printer can't sadly.

Being able to prototype and going commercial are two different things, and I take my hat off to those who have created the ability to produce in decent volume.

udo's picture
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udo Monday, 14 Jun 2021 at 5:10pm

Cheers VJ, i think a FCS to single fin box adaptor is / was a 3hr print

Just saw this..classic

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birdfood Monday, 14 Jun 2021 at 9:22pm

If you can be bothered Udo I think you could make what you're after with silocone molds, no high tech equipment necessary. You could make a mold of a futures base, fill this up with resin and milled fibre and then sit an FCS1 fin in the resin with mold release coated on the tabs. Set the angle you desire and let it cure. Hopefully the mold release works and you should be able to remove the fin from the casting and the casting from the silicone mold. You'd need to manually clean the end result and tap screws in, but it would work in theory. Something like this:

brutus I'm definitely with you in wanting the ability to move my fins around on my boards a bit. This is an aspect of riding a single fin that I really appreciate and at the very least can see the benefits of being able to slide the centre fin of a thruster forward and back. I recently saw NPJ mention setting a thruster centre at 3 3/4 and for me to try that currently I'd need to build a whole new board! Putting a little slot box in is definitely appealing for this reason.

philosurphizing... exciting stuff! I reckon you could get away with jut trimming the fin to start with so long as it was long enough to engage both screws? The single tab lateral screw box is definitely my favourite design.

udo's picture
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udo Tuesday, 15 Jun 2021 at 9:00pm

Long Base on these Groundy

groundswell's picture
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groundswell Tuesday, 15 Jun 2021 at 9:57pm

They look good udo never tried a shape like that myself, i usually go for more keel shapes on twins but id like to give those a go.

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tango Tuesday, 15 Jun 2021 at 11:03pm

I've ridden c-drives a fair bit and those alkalis seem to adopt the same principe of long base for hold and narrow tip for release off the top. I know a fella who rides large c-drives for a twinny, too and they go well.

FWIW, I read an article in Tracks eons ago (late 90s) with Grant Miller talking about his low-rocketed high volume designs. I'd been riding a 7'7" single a lot from 96-98 - flat as a pancake, enormous vee through the tail, rolled 50/50 rails throughout and made by a fella called Terry Clarke I think. All the same stuff Grant was advocating, which was completely anti-banana at the time. A great shame that a mate of a mate snapped it for me.

Anyway, with all that synergy, Grant made me a 6'8 Waterskate as a 2+1 and, rather than put a box in it for the single, he put in 5 x FCS1 plugs and made me a custom fin for it with 4 tabs so you could move it around. It's still in the garage and goes great, though I added a rear plug and spent more time on it as a thruster.

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tango Wednesday, 16 Jun 2021 at 7:27am

Anyone have any experience with the cdrives for futures? That cutaway at the base looks like it reduces the base in contact with the board and would cause a lot of turbulence...?

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brutus Wednesday, 16 Jun 2021 at 9:15am

tango wrote: Anyone have any experience with the cdrives for futures? That cutaway at the base looks like it reduces the base in contact with the board and would cause a lot of turbulence...?

I ride c-drives in all my boards , because of the long base that sits flush on the board , I put them 1/2" further forward.......the Futures ones don't work nearly as well as a twin Tab, because the Futures base only goes to the end of the box and the affect of the cutaway at the back of the C-drive base....you lose a lot of drive!

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udo Wednesday, 16 Jun 2021 at 9:51am
philosurphizingkerching's picture
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philosurphizing... Friday, 18 Jun 2021 at 7:55pm

Here are the results of my moveable fin experiment.
The following photo shows 22mm cut off the 74mm tab.
2 elongated slots routered into the tab, router depth set at 1 1/2 mm, slots are 18mm long, note how the slots in the 2 tabs on the plastic fin are only 12mm long.
Fin box now has grub screw in middle plug giving me a choice of 2 fin positions, in each position the fin tab is secured by 2 grub screws.
IMG-2419

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philosurphizing... Friday, 18 Jun 2021 at 8:12pm

This photo shows the fin set at the back of the finbox.
The 18mm routered slot also allows the fin to be moved forward 6mm.
IMG-2423

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philosurphizing... Friday, 18 Jun 2021 at 8:28pm

Drilling the hole for the middle plug was fairly straight forward.
I screwed a long screw into one of the end plugs which gave me a sight line to drill at the same angle, firstly drilled with a 2mm pilot drill then with a 3.5mm drill which is the size for the 3/16'' tap.
The fin box is sitting in a vice on the pedestal drill, nice and accurate.
IMG-2410

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philosurphizing... Friday, 18 Jun 2021 at 8:42pm

These triple plug single 74mm slot fin boxes are easy to install, all you need is 2 hole saws, 30mm for the 2 outside plugs and 28mm for the middle plug, when I measured the middle plug with vernier calipers the top measures 25mm and the base 26mm, the slight taper a positive design feature.
Here is the wooden jig.
IMG-2424

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brutus Saturday, 19 Jun 2021 at 9:15am

udo wrote: No need for the rear cutaway with FCS ..or is it there for Release ?
https://www.surffcs.com.au/products/fcs-ii-rob-machado-keel-fins

NVS also
https://www.surfnvs.com/collections/twin/products/marlin-twin-medium

Usually the cutaway at the back of a fin , is for allowing the fin to easily enter the fin system at the expense of performance.......the NVS fins are incredible as you can get them in G10 .....which means a thinner fin , less drag and superior flex......

udo's picture
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udo Saturday, 19 Jun 2021 at 9:25am

i understand the cutaway for Futures fin install
But its not necessary for FCS

indo-dreaming's picture
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indo-dreaming Saturday, 19 Jun 2021 at 9:43am

Good thread, interesting discussion, dont have much to add though, i went through a phase were i was buying and trying all types of fins, but now i just stick to my go too sets.

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brutus Saturday, 19 Jun 2021 at 10:00am

udo wrote: i understand the cutaway for Futures fin install
But its not necessary for FCS

I have never really used FCS II as I think they are just too over engineered.....I wonder if the small cutaway is there because of the longer bases than the boxes , which means getting them in OK , but getting them out could do damage to the area behind the finbox.

One of the big problems we have designing anything new for surfboards is we are hamstrung by technology that really limits pushing design theories and R&D .....after testing so many fins , especially in tow boards where we can push testing limits way beyond paddle s/bds....it all came down to using really refined G10 material , with double foiled fins ...which now is used in all paddle guns........

Island Bay's picture
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Island Bay Saturday, 19 Jun 2021 at 11:11am

brutus wrote:
udo wrote: No need for the rear cutaway with FCS ..or is it there for Release ?
https://www.surffcs.com.au/products/fcs-ii-rob-machado-keel-fins

NVS also
https://www.surfnvs.com/collections/twin/products/marlin-twin-medium

Usually the cutaway at the back of a fin , is for allowing the fin to easily enter the fin system at the expense of performance.......the NVS fins are incredible as you can get them in G10 .....which means a thinner fin , less drag and superior flex......

Hey MC.

Have you tried other NVS fins than C-Drives for your paddle guns? Been using the Bronn Quads (80/20 profile on the rears) on my 8'6 and they feel great.

What other G10 fins are common in guns?

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brutus Saturday, 19 Jun 2021 at 1:40pm

Island Bay wrote:
brutus wrote:
udo wrote: No need for the rear cutaway with FCS ..or is it there for Release ?
https://www.surffcs.com.au/products/fcs-ii-rob-machado-keel-fins

NVS also
https://www.surfnvs.com/collections/twin/products/marlin-twin-medium

Usually the cutaway at the back of a fin , is for allowing the fin to easily enter the fin system at the expense of performance.......the NVS fins are incredible as you can get them in G10 .....which means a thinner fin , less drag and superior flex......

Hey MC.

Have you tried other NVS fins than C-Drives for your paddle guns? Been using the Bronn Quads (80/20 profile on the rears) on my 8'6 and they feel great.

What other G10 fins are common in guns?

yeah , tried a few traditional templates , and actually just did an old TC template with them in 4.5 & 4.8..........usually the double foil fins are made for Tow bds.......I am actually currently trying to get a step up fin that is double foiled.........not too much has been done in getting high performance fins made and tested.....just about all the supa tek /carbon/core matt etc is just marketing bullshit....you can't go wrong with 100% fibreglass which is well foiled!