flyingmujol said..
An extract from that interview:

So, what is your favorite equipment setup right now?One of my favorite set ups is the Duotone Super Hero 4,2 on the new Fanatic Grip 81. I use 33" Duotone harness lines and the Grip 81 with a quad fin setup. I use 14.5 rears 8 or 8.5 fronts custom fins. I set up the rears to go right under my back foot and then I put the side fins about 2 fingers apart from the rears. I will put my top turn rail side about 0.5 cm to 0.75 cm further back than the bottom turn rail side. I personally use asymmetric sides that are 8 cm and have 3 degrees toe in, that makes the board turn better, but you do sacrifice comfort and planning. I use the mast track that the disc starts right at the edge of the square, to allow the board to be a bit more free and reactive, once again though that comes with a comfort and planning compromise as the board will feel more nervous under feet. I use this setup for down the line to side on wave riding. When it's onshore I use some normal 9 cm sides, nothing crazy just a straight fast fin.

Thx for posting.

good to know exactly what he said including his onshore setup.

Thats not the interview I saw .... but in the youtube vid .... grip set up ....

" a quad set-up gonna suit that board a bit more (talking about the grip) , it was getting a bit stiff with the thruster ........and then what I did - I put the assymetric quads on the side , about 3 degrees I guess , and then the board just came ALIVE .... " hmmm

My view also , 'A' reason top sailors would possibly go to normal fronts for side onshore - is for all the trick moves ... theyre maybe slightly easier - the 'lack' of grip either way creates easier rotations and sliding back moments where assy's try and dig a little more one way or the other .... For average punters who are focused on RIDING - and not really doing takas and wavshakas - thats not a consideration .... I also think Pare might still throw a bone to the stock set-up - is because thats what his 'sponsors' boards come with

Have a look at Jaegar Stones side on riding boards - even at pozo - he was using heavily toed and canted fins - and he probably has the most expansive waverding syle of anyone in side-on ........ ( and don't remember him sailing too slow either ... when launching push forwards)

Anyways - for those interested in waveriding - try them - try some ezzy 3 deg 8's or 10's , and see if you like ... IF there is any loss in speed sailing around (I dont think so personally) .... then for me there's a gain in speed frontside - as you can commit harder and the board will accept more drive and power ....

If grooveriding and chop bothering is the goal (??!!) , then stick with stock straights and don't own extra fins and options and you'll be happy (WEF)

Around 2005 I was experimenting with the 4wfs. This system lets you change the toe-in angle on the beach without changing anything else. In one afternoon we found out that about 1.8 to 2? toe in with symmetrical fins was the fastest. With more, the turning got even better but was slowing down again. Because the speed also got better, it was obvious this must be because of the flow under the board. I figured the board was pushing the water out. But that this effect would diminish going deeper. It was not untill 2010 that I had a student in hydrodynamics who had a program to do cumputer fluid dynamics. This showed that at about 14cm depth, the flow defelction was gone and that it was about 4? directly at the bottom. So the 1.8-2? average toe in we had found seemed pretty correct, just that, ideally, it should have 4? at the base and zero at the tip: hence a pretwist. As water has 730 times!! more power than air, this does give a significant difference. We also see similar things all around us: Windmills have a twist in the blades, our sails need a different angle of attack in the foot than in the top as the wind higher up is stronger. With the CFD we could also test what influence different bottom shapes have and that the position of the fin also matters but not that much. For example between a single concave and a V bottom about 0.3?.So, if you have simple symmetrical fins, about 1.8 to 2? is good. But I have heard of quite a few people who said: "I tried toe-in but it made no difference". Did you just change the toe-in or were the fins also asymmetrical? They were asymmetrical. So once you change 2 things at the same time, you don?t know what is causing what. What happens you can see here:

I?d estimate that these yellow fins have at least 3% asymmetry. So in effect they would need 5? toe-in. Still then they do not have pretwist but that is more a matter to reduce drag than improve turning.
CFD can do so much more than what we can feel and already to feel we?d need laboratory like conditions, which is difficult. It can tell us what each fin seperately is doing in stead of the result of the whole cluster. We simulated 3 basic important situations in wave sailing: going DTL (this is the most important situation, you do not want any side ways pressure from the sail, no fin should give any lift to make it the best starting position to enter a turn (like Ola explained) and to reduce drag), going up wind (so all 3 fins with an average angle of attack) and a hard turn (with the outer fin leaving the water and a high angle of attack). What we found is that once you get the DTL situation right, this is also nearly always the best for the other 2 situations. Just in extreme situations more or less toe-in could be a little better but you would lose in other areas.And in practice this showed to work very well. We have replaced the fins on a Pyramid 96 from 11+19 to 13.5+14 and the guy was amazed. Incredible in his own words. He was turing loads better, with more speed, keeping speed better or as he said it felt like he was excellerating through the turn, had more control and was going up wind loads better. It was even visible from the beach. Also last summer I had an italian PWA rider FM training here but Iberia had lost his equipment and had said he could rent equipment for the time being. Also he was amazed. The same thing: turning was soo much easier, more speed on the wave, more control, more up wind. He even kept it when his equipment had arrived to test it 1:1 against eachother to see if it had not been his imagination. It had not. Unfortunately we can?t afford to sponsor PWA riders.Here is for example the GPS data from someone on a Witchcraft Wave V3 95 from 2010 fitted with the 2015 model pretwisted fins sailing One Eye @ Mauritius in very marginal winds (see the average speed is low as he had to float out) in january 2023 vs a session in november 2022 with the old symmetrical fins from 2010 with 2? toe-in in windier conditions. Check the difference in top speed reached when going DTL. 31.1 knots is extremely fast and even more so in such light winds.


Here is also a little clip from Scotland with 2 95L Freewave boards, one a 25cm single fin and the other a trifin board with a 20cm centre fin and 10.5 pre-twisted side fins with 4.5? toe-in. They also swapped with a similar result.

By camber do you do not mean cant - you do mean camber like surf fins have..... being the inside foil curve / trailing edge not 'in line' with the LE?


The captions for image 2 and image 3 say the complete opposite about its effect when turning.

BOUKE ....... " I?d estimate that these yellow fins have at least 3% asymmetry. So in effect they would need 5? toe-in. Still then they do not have pretwist but that is more a matter to reduce drag than improve turning."

Ive thrown 3 deg k4's in a couple of custom Quatro's that have around 1.6 degree natural box toe , so getting on for 4.6 deg total - and it was too much - board had an evil tight bottom turn , very vert etc .... but I couldn't draw out powerful enough turns off the top - board would carve too tight and quick .... so I run the custom Quatro's with 1 deg Ezzy 's k4 and they work amazing (2 deg didn't work good either - somehow the maths doesn't add up with Quatro custom boxes and 2 degrees - as should be perfect ! - maybe the 2 deg need to be slightly further fwd in the box - afterthought )

In straight boxes I find the 3 deg best ..... EXCEPT say with something with a slightly rail curvier board in front of front strap like Tabou dacurve (ie DTL model but still with a few onshore sacrifices ) - that works best with 2 deg to add more drive bottom and top turns ... btw - I feel I get very very fast bottom turn speeds with straight boxes and 3 deg k4's - and epic drivey turns off the bottom and top

Ive experimented with more equal sized thruster set-up - with big photo k4 toed fronts - didn't like too much .... back felt a bit too 'loose' - but this is without obviously pre-twist fins that must have an beneficial impact on longer fronts (say 14's etc) , and add drive over that pre-twist ...

Before k4's - I was having too butcher surf fin bases and get them into slot boxes - which was PITA ---- so k4 FRONTS has made my life alot easier with more fun and performance on the water -

Bouke-Witchcraft said..

seabreezer said..
BOUKE ....... " I?d estimate that these yellow fins have at least 3% asymmetry. So in effect they would need 5? toe-in. Still then they do not have pretwist but that is more a matter to reduce drag than improve turning."

Ive thrown 3 deg k4's in a couple of custom Quatro's that have around 1.6 degree natural box toe , so getting on for 4.6 deg total - and it was too much - board had an evil tight bottom turn , very vert etc .... but I couldn't draw out powerful enough turns off the top - board would carve too tight and quick .... so I run the custom Quatro's with 1 deg Ezzy 's k4 and they work amazing (2 deg didn't work good either - somehow the maths doesn't add up with Quatro custom boxes and 2 degrees - as should be perfect ! - maybe the 2 deg need to be slightly further fwd in the box - afterthought )

In straight boxes I find the 3 deg best ..... EXCEPT say with something with a slightly rail curvier board in front of front strap like Tabou dacurve (ie DTL model but still with a few onshore sacrifices ) - that works best with 2 deg to add more drive bottom and top turns ... btw - I feel I get very very fast bottom turn speeds with straight boxes and 3 deg k4's - and epic drivey turns off the bottom and top

Ive experimented with more equal sized thruster set-up - with big photo k4 toed fronts - didn't like too much .... back felt a bit too 'loose' - but this is without obviously pre-twist fins that must have an beneficial impact on longer fronts (say 14's etc) , and add drive over that pre-twist ...

Before k4's - I was having too butcher surf fin bases and get them into slot boxes - which was PITA ---- so k4 FRONTS has made my life alot easier with more fun and performance on the water -

Good, sounds like you?ve put in a lot of testing to get these to work well enough for you. We tried the K4 Ezzys for a bit, years ago but my team rider Will Ward didn?t like them at all, he went back after 3 waves. He likes hollow powerful waves like we have on Fuerte at Cotillo and pushes hard on the fins. The fins need to give a lot of precision. He said he felt the board was all over the place but not where he wanted. Which is down to the material and shape. Add to that the lower up wind performance and speed and it was a no brainer. So that is all the experience we had with them and can?t say much else. I use them in rental SUP?s as there it is good they flex more, they are cheap and robust. I do believe they provide advantages over the provided fins.

When you change the fins on a pyramid to 3 more equal sized fins, the trim changes a bit so you will need to put the centre fin all the way back and maybe the straps a bit more forward. And indeed the Quatro customs have toe-in but the production boards dont. Dont know why.

Conversely of course we have Graham Ezzy, loves the 'Ezzy' fronts, sails them in a multitude of spots but mostly the powerful waves on Maui. Presumably a far heavier and more powerful sailor than Will, from what I've seen of Will. Much prefers the softer Ezzy fins to our stiffer A.I's and all the proto's we've made in stiffer materials.

As I'm sure you must know Bouke, one persons feedback (especially after just 3 waves on one day), means absolutely nothing. I've literally hundreds of people giving me feedback. Preferences can vary hugely.

I've had plenty of feedback on your fins over the years too as it happens.

Happy shredding (Shaka)

Bouke-Witchcraft said..

seabreezer said..
BOUKE ....... " I?d estimate that these yellow fins have at least 3% asymmetry. So in effect they would need 5? toe-in. Still then they do not have pretwist but that is more a matter to reduce drag than improve turning."

Ive thrown 3 deg k4's in a couple of custom Quatro's that have around 1.6 degree natural box toe , so getting on for 4.6 deg total - and it was too much - board had an evil tight bottom turn , very vert etc .... but I couldn't draw out powerful enough turns off the top - board would carve too tight and quick .... so I run the custom Quatro's with 1 deg Ezzy 's k4 and they work amazing (2 deg didn't work good either - somehow the maths doesn't add up with Quatro custom boxes and 2 degrees - as should be perfect ! - maybe the 2 deg need to be slightly further fwd in the box - afterthought )

In straight boxes I find the 3 deg best ..... EXCEPT say with something with a slightly rail curvier board in front of front strap like Tabou dacurve (ie DTL model but still with a few onshore sacrifices ) - that works best with 2 deg to add more drive bottom and top turns ... btw - I feel I get very very fast bottom turn speeds with straight boxes and 3 deg k4's - and epic drivey turns off the bottom and top

Ive experimented with more equal sized thruster set-up - with big photo k4 toed fronts - didn't like too much .... back felt a bit too 'loose' - but this is without obviously pre-twist fins that must have an beneficial impact on longer fronts (say 14's etc) , and add drive over that pre-twist ...

Before k4's - I was having too butcher surf fin bases and get them into slot boxes - which was PITA ---- so k4 FRONTS has made my life alot easier with more fun and performance on the water -

Good, sounds like you?ve put in a lot of testing to get these to work well enough for you. We tried the K4 Ezzys for a bit, years ago but my team rider Will Ward didn?t like them at all, he went back after 3 waves. He likes hollow powerful waves like we have on Fuerte at Cotillo and pushes hard on the fins. The fins need to give a lot of precision. He said he felt the board was all over the place but not where he wanted. Which is down to the material and shape. Add to that the lower up wind performance and speed and it was a no brainer. So that is all the experience we had with them and can?t say much else. I use them in rental SUP?s as there it is good they flex more, they are cheap and robust. I do believe they provide advantages over the provided fins.

When you change the fins on a pyramid to 3 more equal sized fins, the trim changes a bit so you will need to put the centre fin all the way back and maybe the straps a bit more forward. And indeed the Quatro customs have toe-in but the production boards dont. Dont know why.

I would say - Im probably pushing alot harder on the fins in fast side off drawn out bottom turns open fast reef breaks with 15+ sec period ..... vs a slowish dogged start-due to dodgy 5.0 side shore trades .... sandbar closeout wave like cotillo , where you have a stall - then little quick whip bottom turn (no runway whatsoever) and quick whip accelerate and then its over type set-up ... speeds / loading not really comparable ... .... ie think of loading on fins slow side shore cotillo (with current) vs say One eye ... different ball game loading wise ... so don't agree there Bouke ....

and if k4's ever felt dubious at fast speeds - they would be in the bin ! .... I think also there's limitations in super stiff fronts overpowered side off 4.0 , no forgiveness - slipping discs every top turn etc etc board still going one way when your trying to re-adjust lines ...

But for sure we agree .... TOE IS GOOD (and don't know why / what the production outfits are on setting straight fronts )

DunkO said..
I've done some pretty rigorous testing of fins myself. first shot is results of stock fins. Second is results of Witchcraft toey rakey twisty sci fi fins.
I heard Graham uses custom fins with K4 spray job.

As it happens, about 10 years back Graham did try a different brand rear fin whilst he was on Maui which he sprayed yellow. I told him that's not what we're about and he must never do it again. If he wants to try a different brand fin just use it as it is.

The funny thing is the fins our team riders are using are exactly the same as you can buy in the shop. Which is definitely not the case with some other notable fin brands.
Nasty gash that one, and not as uncommon as you might think.

Thanks Seabreezer for the props

Everybody wants a different fin with a different twist or a different stiff combined with a different foil to suit a particular toe that works best for a certain wave on a certain day.

and yet the question gets asked. Why do production boards have straight fins..

SteveThorp said..

Bouke-Witchcraft said..

seabreezer said..
BOUKE ....... " I?d estimate that these yellow fins have at least 3% asymmetry. So in effect they would need 5? toe-in. Still then they do not have pretwist but that is more a matter to reduce drag than improve turning."

Ive thrown 3 deg k4's in a couple of custom Quatro's that have around 1.6 degree natural box toe , so getting on for 4.6 deg total - and it was too much - board had an evil tight bottom turn , very vert etc .... but I couldn't draw out powerful enough turns off the top - board would carve too tight and quick .... so I run the custom Quatro's with 1 deg Ezzy 's k4 and they work amazing (2 deg didn't work good either - somehow the maths doesn't add up with Quatro custom boxes and 2 degrees - as should be perfect ! - maybe the 2 deg need to be slightly further fwd in the box - afterthought )

In straight boxes I find the 3 deg best ..... EXCEPT say with something with a slightly rail curvier board in front of front strap like Tabou dacurve (ie DTL model but still with a few onshore sacrifices ) - that works best with 2 deg to add more drive bottom and top turns ... btw - I feel I get very very fast bottom turn speeds with straight boxes and 3 deg k4's - and epic drivey turns off the bottom and top

Ive experimented with more equal sized thruster set-up - with big photo k4 toed fronts - didn't like too much .... back felt a bit too 'loose' - but this is without obviously pre-twist fins that must have an beneficial impact on longer fronts (say 14's etc) , and add drive over that pre-twist ...

Before k4's - I was having too butcher surf fin bases and get them into slot boxes - which was PITA ---- so k4 FRONTS has made my life alot easier with more fun and performance on the water -

Good, sounds like you?ve put in a lot of testing to get these to work well enough for you. We tried the K4 Ezzys for a bit, years ago but my team rider Will Ward didn?t like them at all, he went back after 3 waves. He likes hollow powerful waves like we have on Fuerte at Cotillo and pushes hard on the fins. The fins need to give a lot of precision. He said he felt the board was all over the place but not where he wanted. Which is down to the material and shape. Add to that the lower up wind performance and speed and it was a no brainer. So that is all the experience we had with them and can?t say much else. I use them in rental SUP?s as there it is good they flex more, they are cheap and robust. I do believe they provide advantages over the provided fins.

When you change the fins on a pyramid to 3 more equal sized fins, the trim changes a bit so you will need to put the centre fin all the way back and maybe the straps a bit more forward. And indeed the Quatro customs have toe-in but the production boards dont. Dont know why.

Conversely of course we have Graham Ezzy, loves the 'Ezzy' fronts, sails them in a multitude of spots but mostly the powerful waves on Maui. Presumably a far heavier and more powerful sailor than Will, from what I've seen of Will. Much prefers the softer Ezzy fins to our stiffer A.I's and all the proto's we've made in stiffer materials.

As I'm sure you must know Bouke, one persons feedback (especially after just 3 waves on one day), means absolutely nothing. I've literally hundreds of people giving me feedback. Preferences can vary hugely.

I've had plenty of feedback on your fins over the years too as it happens.

Happy shredding (Shaka)

Yes, that is why I said that he likes to push really hard on his fins and rail, he likes that he can really depend on his gear. Also Hookipa is a much different wave, with loads more forward speed (towards the beach), Will said you hardly have to bottom turn there as the wave will come towards you. Cotillo is very different, the sea bottom rises fast so the wave does not really have time to build up and once the wave goes steep it about stops dead in its tracks, there is far less forward speed, just the lip keeps going forwards which makes it so powerful. So you have to carve back hard and come from under the lip as there are no sections like in Hookipa. You can hardly make a top turn as between being steep and and the whole lip coming crashing down is very little time so unless you make a top turn when the wave is not really steep yet, most of the time you have to make an aerial to not get buried. It is much harder to keep speed and many struggle, plus your timing and precision needs to be spot on. Will is a very demanding sailor, he wants to sail like that and if he cant he is not happy. Much different than for example Yannick Anton, who, with anything new, will first try gently to get a feel where the limits are. Yannick can sail anything and make it look good. Still he also likes really dependable gear when it gets big. When it is over 6m, he will use a bigger 17cm or 18.5 centre fin and he is only like 58kg. In december we had some big conditions and he took an 86L Haka with a 18.5cm fin of what I said would be way too big for him but he ripped on it. But he also went out in double mast waves in float n ride conditions on his own on a 74L which he can still uphaul. Yannick had to stop competing in the PWA after ripping the ligaments in his knee twice and he has to be more in control because of that than fx Thomas Traversa but he still sails extremely well, especially when it is big. You can regularly see Thomas losing grip on big waves, he must have some balls.But just like you, I also get lots of direct feedback from customers, both people who have bought the gear, rental customers of whom at home often use different equipment and people who bought our fins for other brands boards. I directly talk to hundreds of customers every year.

Bouke-Witchcraft said..

Gestalt said..
Everybody wants a different fin with a different twist or a different stiff combined with a different foil to suit a particular toe that works best for a certain wave on a certain day.

and yet the question gets asked. Why do production boards have straight fins..

I have to say, we hardly ever change fins. Most of us never do once they found the right size (Which in 90% is the standard size) and the fins stay in there for years for all conditions from small to big and from light to strong.

So Steve can sell more fins.....:)Only joking, that is just a side effect, not the reason. But you can ask yourself, why would they? To find the right amount of toe-in, asymmetrical fins let alone pre twist fins and offer more sizes, which all takes an effort to develop and is more costly to produce and stock. For many people there simply is no alternative so why would they if they sell boards like this just as well anyway? Like the saying goes: Necessity is the mot her of all innovation.

Let's also not forget that boards with less toe have less drag and are faster making them work in more all round conditions for more types of sailors at more locations. not to forget symmetric fins provide more options when it comes to buying fins or using existing fins.


If the sailor then wants more toe to bias the board to turning on a particular day or to slow the board down to better match the wave speed they can get some k4 asst fins to suit

seems like a win win not to have boards that require one specific fin from one specific manufacturer.

Bouke-Witchcraft said..

Gestalt said..

Bouke-Witchcraft said..





I

I Gestalt said..
Everybody wants a different fin with a different twist or a different stiff combined with a different foil to suit a particular toe that works best for a certain wave on a certain day.

and yet the question gets asked. Why do production boards have straight fins..

I have to say, we hardly ever change fins. Most of us never do once they found the right size (Which in 90% is the standard size) and the fins stay in there for years for all conditions from small to big and from light to strong.

So Steve can sell more fins.....:)Only joking, that is just a side effect, not the reason. But you can ask yourself, why would they? To find the right amount of toe-in, asymmetrical fins let alone pre twist fins and offer more sizes, which all takes an effort to develop and is more costly to produce and stock. For many people there simply is no alternative so why would they if they sell boards like this just as well anyway? Like the saying goes: Necessity is the mot her of all innovation.

Let's also not forget that boards with less toe have less drag and are faster making them work in more all round conditions for more types of sailors at more locations. not to forget symmetric fins provide more options when it comes to buying fins or using existing fins.


If the sailor then wants more toe to bias the board to turning on a particular day or to slow the board down to better match the wave speed they can get some k4 asst fins to suit

seems like a win win not to have boards that require one specific fin from one specific manufacturer.

I tend to think the other way around, the shaper/manufacturer should provide the fins that work well in most if not all conditions. End users should not have to figure this out for themselves. But untill that happens, it is good that at least you have the option of some improvement with alternative fins. There really are hardly any conditions that would need more or less toe-in. As shown, the pre twisted fins work very well at over 30 knots of speed at One Eye Mauritius but also work well in mushy on shore condition. Plus good quality G10 fins last a looong time if you do not hit them full speed on rocks or so. And the advantage of multi fins is that you can cover a wide range of conditions and wind strengths.

Agree and I think that's the point of why boards are provided with no toe. Ie. manufacturers trying to provide an option that works well in most if not all conditions where end users don't have to figure anything out.

seabreezer said..

Bouke-Witchcraft said..

seabreezer said..
BOUKE ....... " I?d estimate that these yellow fins have at least 3% asymmetry. So in effect they would need 5? toe-in. Still then they do not have pretwist but that is more a matter to reduce drag than improve turning."

Ive thrown 3 deg k4's in a couple of custom Quatro's that have around 1.6 degree natural box toe , so getting on for 4.6 deg total - and it was too much - board had an evil tight bottom turn , very vert etc .... but I couldn't draw out powerful enough turns off the top - board would carve too tight and quick .... so I run the custom Quatro's with 1 deg Ezzy 's k4 and they work amazing (2 deg didn't work good either - somehow the maths doesn't add up with Quatro custom boxes and 2 degrees - as should be perfect ! - maybe the 2 deg need to be slightly further fwd in the box - afterthought )

In straight boxes I find the 3 deg best ..... EXCEPT say with something with a slightly rail curvier board in front of front strap like Tabou dacurve (ie DTL model but still with a few onshore sacrifices ) - that works best with 2 deg to add more drive bottom and top turns ... btw - I feel I get very very fast bottom turn speeds with straight boxes and 3 deg k4's - and epic drivey turns off the bottom and top

Ive experimented with more equal sized thruster set-up - with big photo k4 toed fronts - didn't like too much .... back felt a bit too 'loose' - but this is without obviously pre-twist fins that must have an beneficial impact on longer fronts (say 14's etc) , and add drive over that pre-twist ...

Before k4's - I was having too butcher surf fin bases and get them into slot boxes - which was PITA ---- so k4 FRONTS has made my life alot easier with more fun and performance on the water -

Good, sounds like you?ve put in a lot of testing to get these to work well enough for you. We tried the K4 Ezzys for a bit, years ago but my team rider Will Ward didn?t like them at all, he went back after 3 waves. He likes hollow powerful waves like we have on Fuerte at Cotillo and pushes hard on the fins. The fins need to give a lot of precision. He said he felt the board was all over the place but not where he wanted. Which is down to the material and shape. Add to that the lower up wind performance and speed and it was a no brainer. So that is all the experience we had with them and can?t say much else. I use them in rental SUP?s as there it is good they flex more, they are cheap and robust. I do believe they provide advantages over the provided fins.

When you change the fins on a pyramid to 3 more equal sized fins, the trim changes a bit so you will need to put the centre fin all the way back and maybe the straps a bit more forward. And indeed the Quatro customs have toe-in but the production boards dont. Dont know why.

I would say - Im probably pushing alot harder on the fins in fast side off drawn out bottom turns open fast reef breaks with 15+ sec period ..... vs a slowish dogged start-due to dodgy 5.0 side shore trades .... sandbar closeout wave like cotillo , where you have a stall - then little quick whip bottom turn (no runway whatsoever) and quick whip accelerate and then its over type set-up ... speeds / loading not really comparable ... .... ie think of loading on fins slow side shore cotillo (with current) vs say One eye ... different ball game loading wise ... so don't agree there Bouke ....

and if k4's ever felt dubious at fast speeds - they would be in the bin ! .... I think also there's limitations in super stiff fronts overpowered side off 4.0 , no forgiveness - slipping discs every top turn etc etc board still going one way when your trying to re-adjust lines ...

But for sure we agree .... TOE IS GOOD (and don't know why / what the production outfits are on setting straight fronts )

Yes, the lift a foil generates increases exponentially with the speed. So if you go 20% faster, fin lift (and board lift) increases by 44%. Or if you go 50% faster all forces (per cm2) are 2.25 times higher and if you go twice as fast, (which is well possible in ground swell conditions, see the speeds at One Eye) forces are 4 times higher. So indeed when you go fast it is much easier to push harder. The other way around it also works like that, with 20% less speed, the force of the water on the board and the fins is 36% lower. This physical law is the cause that at some point we need bigger or smaller gear.What could be an interesting experiment is to take your K4 fins with too much toe-in, make them warm with a hot air gun and bend the tip inward so they have pretwist and less toe in at the tip. I am sure at the base there is not too much toe-in but likely at the tip it gets too much. As the tip still have an asymmetrical foil, I do not think you need to go to zero but somewhere around 2 degree. To do this well, ideally would be to clamp the base in a vice and 2 wooden battens clamping the tip.

SamDillon said..
You know what this thread confirms to me, windsurfers are a bunch of nerds. Get out there, sail more and blame your gear less. Check out the stuff top guys were doing over 20 years ago and it's so beyond where most will ever be.

On the flip side K4 flex fins are the sh!t and I'm between 90 and 94kgs. They drive off the bottom and hold off the top rather than just spinning out like all the stiffer ones I've tried. Everyone go buy K4!

Just a small problem there: You need conditions and you need talent.......I bet that 99% of people sail the maximum amount they can and sail at the top of their skills. No one would be typing on here when at the same time she could be out sailing. And even if you do have a surplus of both conditions and talent, good equipment still helps and information like this can help get that.

sprayblaze said..

Bouke-Witchcraft said..

SamDillon said..
You know what this thread confirms to me, windsurfers are a bunch of nerds. Get out there, sail more and blame your gear less. Check out the stuff top guys were doing over 20 years ago and it's so beyond where most will ever be.

On the flip side K4 flex fins are the sh!t and I'm between 90 and 94kgs. They drive off the bottom and hold off the top rather than just spinning out like all the stiffer ones I've tried. Everyone go buy K4!

Just a small problem there: You need conditions and you need talent.......I bet that 99% of people sail the maximum amount they can and sail at the top of their skills. No one would be typing on here when at the same time she could be out sailing. And even if you do have a surplus of both conditions and talent, good equipment still helps and information like this can help get that.

Yeah, K4 all the way!!!!!

Most of us like to experiment to get a certain feeling on waves, and the price of k4s allow for that. for the price of 1 set of G10 side fins, you can get 4 plus sets of k4s, more if second hand. Obviously I would like to try other fins, for example i got some second hand Maui Ultras, didn't like them, but they were cheap. If i was buying them new at full price I'd have been really pissed.