K4 Ezzy Asymmetrical fins

K4 started off with flexier fins designed for multi fin waveboards and for the last few months they have been offering asymmetrical side fins for quad and thruster set ups developed with Graham Ezzy. Here is an article with Steve and Graham Ezzy talking about the development process.
boardseekermag.com/features/is-it-time-to-go-asymmetric/
I've been playing around with them since the start of the year and the findings have been very interesting.

I've nicked Steve Thorp's (the man behind K4) explanation

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For many years all surfboards have been supplied with asymmetric front fins, windsurfing has only just caught on, perhaps in some part due to the extra complication for manufacturers and customers (I'll make this as painless as possible!).
By creating an asymmetric foil you can increase the amount of lift generated whilst keeping the drag low, the same as an aircraft wing. Asymmetric foils are more efficient at creating lift. This means more drive, power, hold and grip when your board is turning without a drag penalty.
Where things become complicated, is that an asymmetric foil will create lift when running 'straight', ie. it will pull to one side. This 'pull' is undesired for several reasons, but mostly that it is causing drag. In order to prevent this we turn the fin in towards the nose of the board until the fin neither pulls one way nor the other. This angle is the 'toe in'. Of course the amount of 'toe in' for no lift (least drag) in a straight line varies depending on board design and how fast you're travelling!

If you don't know what toe in is - there is a brief explanation here http://www.k4fins.com/2013/08/what-is-toe-in/

Surfboard fins have had toe in for ever. As far I'm aware in windsurfing the JP quads had it last year, fanatic are now marketing it on their quads, the nude/starboard have used it on their twin fin set ups and Simmer have also been doing it for a while.

It was only a matter of time until we started putting a bit more tech into wavesailing fins. Surf fins are offered in multiple constructions/materials, foils and outlines. I know when I go surfing I have a few sets and chuck in what ever is most suitable for the conditions. Sooo many people underestimate the difference fins make to boards!

At first glance compared to the symmetrical shark tooth fins - the Ezzys had a wider base, swept back outline - basically with overall more area.









I normally run an 8cm front, 13cm rear quad set up so played around with the 8cm 1 degree and 2 degree sides. My first impressions where 'initially it felt a little stiffer and less 'whippy' but after a few waves I got used to them and they seemed to give more torque back up the wave face, making it easier to go vertical. I think the stubby outline having the extra area was why they felt a bit stiffer rather than the foil/toe, as I used them more it felt like I could really put more power into turns and also they gripped in coming back down from critical smack into air turns whereas my normal set up might not have had the grip to make it.
For straight line I didn't really notice any real loss of early planing or increase of drag and it seemed like they felt more solid underfoot and really cranked upwind.
After a while I swapped to the 2 degrees and instantly noticed they felt draggier. On the wave it felt as though the extra torque was gone and I actually lost speed driving back up the face.'

A few other guys also tried them out in their JPs and basically found the same thing.

Basically for my current boards I've settled on the 1 degree set up for all conditions, small waves, mushy onshore or when it is firing clean down the line. Turning is more of a power gouge feeling, than skatey, and they are fast and grippy. In a straight line they are probably even better than with the symmetrical fins, because of the improved upwind performance.



Recently in Mauritius I was able to try a whole heap of boards and fin set ups back to back. For the JP quads I still found the same thing, that the 2 degrees felt as though you were pushing too much water and didn't really improve turning ability. (I think this is because of the V under the footstraps). In the new thruster though the 2 degrees were awesome, no loss in speed or upwind ability and turned a hell of a lot better than with the stock fins. Will have to measure the boxes, but I suspect the thruster boxes are straight, whereas the quads have close to 1 degree of toe.


Steve's guideline to set up your fins.

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Most boards will perform best when the toe angle is between 2 and 3 degrees. The k4s come with a choice of +1 or +2 degrees added toe. Therefore a board which has straight boxes (zero toe) will need the +2 fins, and a board with 1 degree or more boxes will need the +1.
You can also tune your board with toe in to some degree; small wave surfboards can have over 3 degrees toe, this is to make turns easier and sharper and can do this as the top speed is less important. Big wave surfboards have less toe for more drive, higher speeds and wider turns. You still need to stay within a reasonable range of toe though, so as not to cause unnecessary drag.

To measure the fin set up in your board

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Difference in span between the ends of your front boxes in 'mm' and the angle of toe your boxes have (taking a 10cm box length)

DIFF 0, TOE 0
DIFF 1.75, TOE 0.5
DIFF 3.5, TOE 1.0
DIFF 5.25, TOE 1.5
DIFF 7.5, TOE 2.0

Here's a bit of info that has been collected so far:

Fanatic 93 Quad, 2011, 1 degree. (+1 for speed bias, +2 for turn bias)

JP Quad 2013, 0.9 degrees, requires +1 - based off my experience

Quatro 76 KT, close to zero toe. Requires +2.

Simmer Fly 2012, 1.3 degrees, requires +1.

Starboard quad 2012, 1.7 degrees, requires +1.


Pretty interested to hear if anyone else has given the fins a go yet. Would also be great if people could measure their waveboards and post the findings here. Get out a ruler and measure some fin boxes!

I have played around with symmetrical, 1 degree and 2 degree asymmetric K4 fins on an 86 Fanatic Quad.

2 degree asymmetric side fins work awesome, transforming the board! For down-the-line sailing they are truly sick, allowing me to turn incredibly sharply, gripping the wave to the point that you virtually can't stuff up! Even still, they also still provide good acceleration and power for jumping!

Get some! (Actually...don't because then you might beat me in the next comp :/)

Yeah that is a good starting point but it really just depends on what kind of feel you want out of the board. It seems as though with thrusters people are going towards a much more equal spread in sizing eg. 12 sides, 15 rear especially for riding.

For heavier guys the flex rear fins are pretty soft so you would have to go up a size, but with the stubbies (stiffer and more upright - probably a better choice for 80-85kg plus) I'd say you go the same size.

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Al McLeod said..

Measured a few boards today.

JP Quad 2012 82, zero toe. Requires +2
JP Quad 2012 92, zero toe. Requires +2
JP Thruster 2012 92, zero toe. Requires +2
JP Thruster 2013 99, zero toe. Requires +2
Tabou Pocket 2012 (Thruster) 80 ? zero toe. Requires +2.
Tabou Pocket 2013 (Thruster) 85 ? zero toe. Requires +2.

Tabou Pocket 2012 , 2013 , 2014 (Thruster) 69 , 75 , 80 , 85 , 93 - zero toe.
Tabou Da Curve 2012 , 2013 (Quadster) 67 , 74 , 79 , 85 , 91 - zero toe.
Haven't measure the DC 2014 yet but i am pretty sure it is also 0 degree.




Martin

Gaastra/Tabou/MUF

There is so much salesman talk in there it is not funny.

Toe angle is dependent upon so many things that it is not the case that all modern boards with straight fin setups require toe-in. What, months of development and a few pro riders and they stuffed it up?? All of the manufacturers stuffed it up??!!!
No they didn't....... maybe some tweaking is useful for some riders but we do not ALL necessarily NEED toed-in fins.

The main issue I see is that this all makes it sound like because surfboards have had assy foils and toe-in, then we need it too.
Well race cars run ridiculous toe, camber (cant) angles and we don't need it in what we drive to work.
What is the difference....? Speed. We drive a lot slower to work!!! And we want tyres to last 50,000km not 500km.
A surfboard runs a LOT slower. Surfoard levels of toe-in (and cant for that matter) will induce all kinds of issues in a sailboard.

Then bottom shape - the water flows along the board, and it also diverges laterally. Imagine a cube of foam in the water and then you sit on it. Water underneath will exit in all directions. Same with a windsurfer but at planing speeds, the water exit is more to the rear than the sides (different to sitting on the stationary cube).
A bottom with vee has water exit the rear at a bit of an angle....it is shooting out the back but also diverging laterally like the cube you plonked your ass on. A double concave, less so (kinda like channelling the water to keep it straight) A totally flat bottom is in between. Toe needs to take that into account so the fin angle lines up with water angle.
BUT that is for sailing in a straight line, relevant to bottom shape. Not even taking into account wave riding.... then it gets much more complicated

Then, how close fins are to the rail. If too far out they will want to cavitate in a bottom turn and that was the main thing that made the resurgence of twins fail a few years ago. Cant and toe can fix some of that, but assy foils won't.


In short: it is rubbish to say boards NEED toe in or assymetrical foils. They are a tuning option.... after stap & fin positions fore and aft.

Some people have good results with them but to make it sound like a certain model NEEDS 2deg toe in and/or an assy fin is just madness. (Like your table says)
I'd say the opposite - after much testing, the boards are optimal now for average sailors and you can tweak for yourself with toed-in or assy fins.

Yes, the art of fin swapping seems to have been lost - a single fin can change a lot with sizes and flex/no flex ..... so can a thruster/quad/twin. But the marketing hype by K4 (et al) saying we have to have toe-in is rather obvious sales hype.

"2deg needed"
It is like saying ALL Tabou single fin waveboards in all conditions need a 1cm shorter and more flexy fin. Bullsh1t ... what about heavy guys, choppy waves, glassy waves, current, or karma...???


But yes it is nice to know which boards run how much toe.
But I'd like to know how it as measured as I just measured a board I am building 3 times and got 1.4 deg, 1.5deg and 1.9 deg. many of your "straight aheads" may be one degree in. (and if you believe K4, then that is really fkn significant isn't it )
If it was measured by some dude with a ruler in his shed, I am unconvinced...

Conclusion:
Nice to have the option but we don't need K4 making it sound like we are all going to fail without toe-in
Assymetrical is nice - but not to the extent of surfboards due to the speeds we travel at. You can achieve same with flattening the entry of the INSIDE foil of your own fins with sandpaper ($50 secondhand fins vs $200 for set from UK...hmmm)

^^ James I can't find much info about it. Like just basic rules eg: More cant for fins closer to rail, or less?
Be interested to hear your take on it

Geez Mark you’re making it sounds like someone’s got a gun to your head…

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What, months of development and a few pro riders and they stuffed it up?? All of the manufacturers stuffed it up??!!!

I really think this is a can of worms that is largely unopened, especially in production windsurfing boards. I’ve spoken to a few shapers about it and then are of the perception that any kind of toe in creates drag and makes the board slow. This isn’t true, if you get the angle correct then your waveboard will turn better with no real disadvantage. I suspect we are going to see a lot more of this in the future with waveboard development, it has already begun as I mentioned in the first post…

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A surfboard runs a LOT slower. Surfboard levels of toe-in (and cant for that matter) will induce all kinds of issues in a sailboard.

The first post already talked about toe in differing between small and big wave boards, in windsurfing we are probably more towards the bigger wave performance end of that spectrum as we are travelling faster and utilizing the power of the sail so our turns are naturally wider. With these fins you have the ability to tune your board (like you said) – towards a wider turn bias, or tighter turns by increasing the toe… I agree that going to extreme levels of toe in isn’t good, something I pointed out based off testing out the different fins (2 degree were too draggy in my quad), which is why you need to factor in the angle of the boxes of your boards and is the whole point of the tables to make it clear for everyone.

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Some people have good results with them but to make it sound like a certain model NEEDS 2deg toe in and/or an assy fin is just madness. (Like your table says) I'd say the opposite - after much testing, the boards are optimal now for average sailors and you can tweak for yourself with toed-in or assy fins.

Sure, for the average dude bump n jumpin around on a freestyle wave what’s the point? These are fins designed for multi fin waveboards – twins, thrusters, quads… They are targeted at wavesailors, for wavesailing. Most wavesailors are always going to be interested in an option that lift their performance, just look at the multi fin boards now. Spot the single fin at your local break.

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($50 secondhand fins vs $200 for set from UK...hmmm)

They are $65 – (no sanding required) and coming to a store near you! ;)

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For many years all surfboards have been supplied with asymmetric front fins, windsurfing has only just caught on

Not that new. I sailed a thruster with asymmetric fins in 1987. It was slow though, maybe it didn't have the right toe in?

After reading bucket loads of toe in advice over the last few years from self made internet forum experts on "boards forum"
I have been doing my own experiments with toe in ( I made and sailed toed in twins(and canted) and thrusters back in the late eighties)
So far I have found toe in on quads is totally different to toe in on thrusters and the same angles don't seem to apply.
My advice for the time being would be your wasting your time and money with quad fin toe in at the moment. I think there's probably a reason why the major reputable companies don't have toe in on their quads.
I'm still painfully experimenting with quad fin angles, when I'm finished I'll be writing up a big post on my findings in the boards forum, might put a copy here, if this thread isn't too old by then (can't ad to seabreeze posts if they get too old )
ps the K4's I've tried aren't the best fins, sure they are light and cheap, good to use in rocky fin damaging places places.

Interesting R1DER, that you find different angles ideal on quads vs thruster boards. Are you using the same board and the same front fins when you compare?

Personally, I see toe in as just one tuning variable. There seems to be quite a large range where the toe in has no serious effects on straight line performance, ie drag (large range meaning something like 1.5 degrees). I mean, for a given context there might be an ideal value, but given how a lot of variables change when we sail, I don't think it is a huge deal if you stay within reason.

But once on a wave the toe in has quite significant effects on the feel of the board in the turn. Effectively, more toe in will make the (inner front) fin engage a bit later in the turn. The easiest way I know to explain the feeling is that with a given fin size and position, if you increase toe, the front fin will feel less powerful in the turn entry without really losing drive once you are fully committed to the turn. And conversely.

This means that if you're already committed to a small (low power) front fin (typical windsurf quad style), then there may be reasons to keep toe in low to get a discernible effect from that little fin. But once you move to a bigger and more powerful front fin you will often run into problems with a sketchy turn entry with too little toe in, so more toe in is usually the way to go. But as mentioned, there is a feel/style aspect to this too, even with a given fin size. Asymmetrical fins need to be toed in more, but that is a different issue covered in Withcrafts post above.

For production boards you hence need to find a good compromise. At Simmer we have used between 1.3 and 1.8 degrees for the front fins and the rear fins straight except for the Frugal which has half a degree toe in the back too. This has shown to be a good compromise for symmetrical fins that allows the board to be set up with a wide variety of front fin sizes (from 9cm all the way up to 15cms in some setups). We are still working on our asymmetrical fins, but slightly depending on the foil, I tend to toe them in around 1-1.5 degrees more, but I mould that into the bases so that the same fin box setup works.

On my personal(proto) fins I sometimes put a bit of cant in too. But that's a different discussion...

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R1DER said..

wasting your time and money with quad fin toe in at the moment

I've got to disagree - been trying more angles on my new board (no toe in), 2 degrees was quite decent all round, but now I am pretty much only using the 3 degree fins. The increase in turning ability is huge - excellent for tight radius turns to get back up the face into the pocket. Have to agree with Ola though - there is a sacrifice in straight line and early planing. With the 3 degree set up I've found the board slightly harder to get planing, and it definitely feels twitchier underfoot - like it wants to be cranked into a turn.

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I think there's probably a reason why the major reputable companies don't have toe in on their quads.

Nah a lot of them are starting to do it. And the ones that don't simply have not put this effort into that element of R & D yet.

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Al McLeod said..

R1DER said..



wasting your time and money with quad fin toe in at the moment

I've got to disagree - been trying more angles on my new board (no toe in), 2 degrees was quite decent all round, but now I am pretty much only using the 3 degree fins. The increase in turning ability is huge - excellent for tight radius turns to get back up the face into the pocket. Have to agree with Ola though - there is a sacrifice in straight line and early planing. With the 3 degree set up I've found the board slightly harder to get planing, and it definitely feels twitchier underfoot - like it wants to be cranked into a turn.

I think there's probably a reason why the major reputable companies don't have toe in on their quads.

Nah a lot of them are starting to do it. And the ones that don't simply have not put this effort into that element of R & D yet.

I think the latter is a bit harsh. They make a board for everyone and all conditions (as much as possible)
If you have toe in to the max on a production board, and realise the benefits you speak of, you can't go then backwards.
What I mean is the turning benefits you get may well hinder you in longer faster turns on big waves.
As an analogy in the old single fin day a pro LOVED 21cm fins in his board but it was released with 23cm as the average guy did't do Ho'okipa and was not that good.

So it is better to have a board made "in the middle" and then people can add toe'd in fins.
Else if all boards have 3deg toe in then you can't undo that as nobody is making toe'd OUT fins yet.

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Mark _australia said..

What I mean is the turning benefits you get may well hinder you in longer faster turns on big waves.

Actually it is in big fast waves where not enough toe is worse. When you go DTL with paralel symmetrical fins both fins give about 20-25kg lift outward with an average speed. As long as both fins are still in the water these forces balance eachother, "all" you would notice is increased drag. When you enter a turn and the outside fin releases, the inner fin all of a sudden wants to pull the tail in where you want it to go out, causing the so called straight lining.
I had a customer from Chile who had been on an Angulo single fin for years. When it died he started testing quads from various brands. But he kept on crashing in fast long bottom turns. In Chile they have some long big fast waves and the lift and drag a fin creates increases exponentially with the speed. He did not understand then started to watch videos from Maui and noticed they turned a lot more on the back foot and seemed to know when the board wanted to straight line. He tried this but did not like it much. Then he read my article about the twisted fins and jumped on a plane to test some boards and took 2 back with him. Problem solved, he could make all kinds of turns again without strange side effects.

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Mark _australia said..

Else if all boards have 3deg toe in then you can't undo that as nobody is making toe'd OUT fins yet.

I??ve been testing my pretwisted fins with 6 deg toe at the base (there is 4,5 deg twist in the fin) and it worked fine no problems whatsover. This was just a provisional thing with some bits squeezed in the box and after it broke I went back a bit and now use 5 deg since a long time. I will try 6 deg again but make it solid this time and make a 6 deg twist in the fin. Minituttle is good for this with the screw in the middle and the wider base so you can turn the fin inside the box. My boxes have been at 2 deg since 8 years. Which is a good average amount for symmetrical fins. As I said with an asymmetrical fin you need to add toe, other wise it gets worse. Another big wave rider from Fuerte had a trifin without toe. He wanted to make it turn better so put bigger assymmetrical fins and found the board got a lot worse instead. Up to becoming unsailable. He did not understand since he knew from surfing this is the opposite.

Al

FYI the Fanatic Quad 2014 are measured and confirmed @ 0.7 toe....so ive bought 2 degree offset...will see / might be too much?

PS
What do you put in Quad rears...flexy or stubby design?
My 89 quad fanatic choco G10 are 14.5cm....but i think k4 stubbs are 14 or 16....whilst flexy are 14,15,16
(im about 85kg)

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Witchcraft said.. When you enter a turn and the outside fin releases, the inner fin all of a sudden wants to pull the tail in where you want it to go out,

When it comes to quad toe in this is a very important statement by Witchcraft, on a quad with two fins out of the water there are now only two fins steering the board and with front fin toed in which way is it trying to turn the board in relation to the rear non toed in fin?

So they need additional toe in to turn properly?