GasHazard said..

I don't understand the effect of asymmetry wrt toe-in.

If you change the profile from symmetrical to asymmetrical, the effect is like having no toe-in, the fin starts to give lift (the air plane wing effect), which is bad for turning, and increased drag. So, to get the lift zero again, you need to add toe-in, about 1 degree for every percentage of asymmetry. Then also the drag is reduced again.

Bouke-Witchcraft said..

jontyh said..

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.

I think that people should not need to experiment or at least not with toe-in. The fins that are delivered should be developed for the board to provide close to optimal performance. If you buy a new car you expect it to work well like that as well and you do not have to experiment with the tires?

Perfect example. Cars have toe/camber/ackerman angle etc all set for a neutral steering with some understeer so the average dope has the 'right' kind of crashes that are less significant.

Just toe changes can make a car handle amazingly better. So if you're into cars you fiddle with it. I doubt you'd suggest borderline track setups for all cars from the factory.....?

Everything that is at the higher end of a recreational activity is tunable. Its part of the fun for some folks, others find a board with symmetrical fins set straight a ahead (or a tiny weeny bit of toe as many do) works just fine. We see guys who are top 10 nationally beat pros sometimes, and we know the non-pro-but-very-good-guy is using an off the shelf board and fins. Its not necessary to have all waveboards with assy sides and toe.

As far I get it the new trend is that assys are mandatory for thrusters, not that much, if at all for quads? If you are riding a thruster without assys in front, you are wasting your time-right?

sprayblaze said..
As far I get it the new trend is that assys are mandatory for thrusters, not that much, if at all for quads? If you are riding a thruster without assys in front, you are wasting your time-right?

I would rather say that a thruster or trifin is better than a quad in everything when set up correctly so you can use 3 similar sized fins. But with the side/front fins then being bigger, any mistake in the set up with regard to toe-in, pre-twist or asymmetry (in that order) becomes a lot more noticable. The advantage of a Quad is that there is more area in the training fins so you can use smaller side fins which allows for bigger mistakes in the set up. I remember the first quad of Starboard which had bigger front fins without toe-in and it was a dog. Boardseeker had tested the version with a centre fin box and had found it was straight lining as a Quad and said it works best as a single fin. I also had a customer from Chile around 2011 who used to have a single fin from Angulo but when he broke that, he started testing the quads which were in fashion then and he couldn?t sail them. He liked front footed high speed bottom turns and every time the board went straight when he pushed to tighten the turn, causing him to crash. He then started to watch how the pros ride these boards and said he saw them turning on the back foot and he didn?t like that. Then in 2011 he read an article in Windsurfer International about my pre twisted fins and the explanation and thought that must be the solution. He came over and scored some good conditions and said, yes, this is how it should be: Better upwind and control than a single fin but also more speed than a quad and being able to turn well on either foot at full speed.

Gestalt said..
here is what boardseeker said.

" On the wave face, it grips like nothing we have ever sailed before, turns tightly and holds speed incredibly well, giving a very 'surfy' feel to the way it rides. It also has great control (allowing you to use a bigger board) and this is all combined with excellent upwind ability. On the down side, it doesn't tail slide easily and if pushed very hard in the bottom turn by pro-standard riders, can get a little bit temperamental. It can't be ignored that over the past month, we have let a good number of amateur riders try this board and almost all have come back with a massive smile on their face claiming the board to be something special."

below is what Boards Mag said in their review.

"Overall: The Quad really grew on the team throughout the test. The more someone used it, the more fun they had, and the more waves they tore to pieces on it. If you've got the time to put in and love shredding good cross-shore waves, this could be the board you've been waiting for. It grips harder than any other waveboard we've tested. And if you do get one, you'll be throwing so much spray that anyone watching from the beach will think you're a pro!"

imagine if this board never happened. (i own one),
what a loss for the sport in general. that first board from scotty and starboard revolutionized the sport. (for not the first time...)

boardseekermag.com/news/news-item-2034/

I think they changed the text a bit as I remember they wrote they preferred to sail the convertible as a single fin but this is the part I was referring to:

"The other factor that became an issue with our top level Clones was the bottom turn. Whilst the board grips well, turns tightly and holds speed extremely well for most riders in most instances, there are isolated occasions when pushed very hard that the board objects and decides to stop turning. This seemed to occur mostly when the riders weight ended up being a long way back on the board for whatever reason. For instance, when trying to turn extremely tightly back into the pocket of a small wave at slower speeds. When this happens, it somehow feels like the fins have become unhappy and instead of turning, the rail buries and the board goes straight on leaving the rider to fall between the sail and board in the bottom turn. It's a rare occurrence, but one that left the Quad as a slightly less convincing prospect for our advanced (PWA Standard) Clones in cross-on conditions."

That is that straight lining effect. it happens mostly at the moment when you bank over harder so the outer fins leave the water and it becomes worse at higher speeds when the fins give more lift. It sounds like this test was done in the UK with mostly cross on conditions so most of the time speeds were low to moderate. Also a local rider here had such a board and had that problem, we modified the fins by giving toe-in (with the MT bases you can easily modify the toe-in by grinding off the opposite corners, wax the inside of the box and the screw, turn the fin inside the box and fill the opposite corners with resin) that made it faster but it became too turny as the straps were far back compared to the fins. Also a sign it needs to be turned very much on the back foot. But this does cause a board to stall sooner in lighter conditions. He kept on struggling so we then lateron added some more plugs more forward which restored the balance and it sailed quite well but then the heel areas started cracking.

Marc Par? giving some insights about Fanatic Grips and, of course, talking about fins:

Gestalt said..
seems to go alright in this video.

and this one too. i think this may be v2

It's interesting now to revisit that Peter Hart video from 13 years ago - and to re-evaluate the myths that built up about that first production Quad from Starboard. It's not really about toe in.

People were still feeling their way abound the idea of multi fin boards, and in that video, Peter Hart was simply seeing how learners and intermediate sailors adapted to the new Starboard Quad.
He starts off by telling them to move the front footstraps forward, and to go easy on the backfoot when starting out. So those comments are really about learning to sail a wave board with more weight on the front foot, than they are a comment about quads.

We understand this so much better now.
1) A single fin board takes a lot of backfoot pressure, and you ride the board on its tail at speed with the torque lift from a relatively long fin. We take that idea one step further with our slalom gear where the board is meant to 'fly' on the tail lift from a very long fin.
2) A quad or twin fin board has shorter fins which give less leverage or torque lift at the tail. And what lift there is only comes when the board is moving forwards. So if you have pairs of fins lined up with each other (in a quad or a twin fin) then the fin area feels much less until you start planing. And that is why Hart is warning his clinic students to go easy on the back foot. At that stage, those learners were expecting to load up the board at the tail, like you do with slalom and free ride gear.
3) But with multi fin boards, it's then those shorter fins that help the board turn faster in the gybes, because the torque lift is not controlling the board tail in the gybes, and the front footed sailor can carve/turn on the rail more.
4) That early production Starboard Quad was then criticised for 'straight lining' on the wave sometimes. And some people wrongly said this was because there was no toe in for the front fins.
5) What had actually happened was there was too much fin AREA in the back of the board, and the over-size fins had been fitted to help those learners first using that board.
6) Despite being set up as a Quad, the board produced too much drive (sideways lift) from all four fins when you pushed hard against them in a cranked bottom turn. And the lack of toe in was not the problem - too much fin area was. If you total the amount of fin area used in that board it was way more than the equivalent single fin. (See screen grab picture).
7) So we now know that, for sure, toe in can help a board turn better, but it's still not essential as some would claim. If you want to blast in a straight line then toe in can hold back your top speed or limit your jumping speed on the way out. If you want to turn better on the wave face then, yes try a bit of toe in. But first you should also try a smaller set of fins, and learn to sail the board more off the front foot. This is then just a stance issue: Move your front footstraps forwards, and shift the mast foot back to get the rig - and you - more upright.
8) On topic: There are no rules about toe in. The fins and fin boxes fitted to a board simply have to work with the hull shape and with what the sailor wants to do. The box settings are also a compromise between straight line speed and for turning. One to two degrees of toe in for the thruster boxes is a typical compromise in production wave boards - but some boards continue to have no toe in at all, and they work just fine. If the board tail has a lot of Vee then you might like a bit of toe in and some kant, but many designs have neither and work better that way.

"If you want to blast in a straight line then toe in can hold back your top speed or limit your jumping speed on the way out."

Did you miss the posts about the natural flow direction under the back of the board? If that's correct (and it makes perfect sense) it implies that parallel thrusters can't be working optimally in a straight line.

Haha, I don't think I said I was for or against toed in boxes. What I said was that the fin set up needs to work with the board and that the optimum fin cluster will vary from board to board because of hull shape variations and sailor preferences.

If toe in were to make one board design faster then of course it's a good idea, because if the main aim of toe in is to help the board turn, finding it also helps straight line speed would be a win win situation. For that board.

What we don't want is the blanket claim or rule that ALL wave boards should have toed in boxes, when that's clearly not the case.
If you want to experiment with your fins, to tune them for your local sailing spot, then go ahead. Nowadays, with offset fins readily available from K4, you can increase toe in without needing to change your thruster boxes.
But what we actually find is that some production boards have no or little toe in, and those same boards are winning wave competitions at pro/PWA level.


The Marc Pare tech talk video is interesting - and, as it happens, I know him and Lucas who is interviewing him. They talk about a production board they both sail, the Fanatic Grip, and Marc says he sets his fins up differently compared to his team mate, Victor Fernandez. Fernandez doesn't add toe in or use asymmetric fins, whereas Marc does, and that's simply a tuning choice.

Marc says he prefers asymmetric fins with toe in but doesn't actually say how much toe in - and remember that asymmetric fins need about 2 degrees of toe in just to run at neutral.
Marc then says that set up has the downside of making the ride 'edgy', but he thinks it gives him more 'squirt' in the turns.
He also sets his front fins closer to his back pair when he wants to turn in a tighter arc.

Lucas also asks Marc about fin position, footstrap position, and mast foot position - three of the settings that combine to set up your sailing 'stance'. But it would be odd if Lucas were to copy those same settings for his own board, because Marc is quite a bit taller than him, and with a different leg length and stride width. Sailor weight differences also determine what sort of fin area you have under your feet.

As a last comment from me: I always find it odd that we have heated debates over 1 or 2 degree differences in the angles we set fins at.

When the toe in debate first started, people wrongly referenced surfboards, where toe in angle can be and needs to be much more extreme. Surfboards only need to turn on a wave, and don't plane on the way out. Their energy source is not the wind, but the slope of the wave and the weight and actions of the surfer. On a surfboard, you might push on the fins to generate extra speed on the wave, but we windsurfers are more likely to use our rig power for that.

I see that, ten years on, and now the evidence is in, we windsurfers aren't actually using much toe in at all. All those people who went in the garage and realigned the boxes in their boards must be feeling a bit foolish now.
Those still making great claims for high angles of toe in are only talking about what they think works with their own board shape, or maybe for their unique local conditions.

And K4 fins have also got this laid out quite simply nowadays.
The K4 site helps you work out what, if any, toe in your fin boxes already have. They then recommend to use fins that allow just 1 or 1.5 degrees of toe in.

For asymmetric fins, you need 1 or 2 degrees to allow those fins to work as neutral, and they suggest you add the further 1 or 1.5 degrees to get the optimal water deflection.
So, even for asymmetrical fins, the maximum toe in recommended is 3.5 degrees. With 'normal' or symmetrical fins, the recommendation is 1 or 1.5 degrees.

I'm wondering just how many sailors will notice those small 1 degree differences? And that's why I think all this is a bit of a whitewater storm in a tea cup.
Tuning is fun and can be productive but you will, in my opinion, notice a much bigger difference if you change fin sizes and fin positions.

To Gestalt: This is what happened. Marc Pare went to the Fanatic shaper and said: " I want my Simmer board back."

Basher said..
As a last comment from me: I always find it odd that we have heated debates over 1 or 2 degree differences in the angles we set fins at.

Because the force of water is about 730 times higher than that of air. Or in other words, stick a fin out of the car window with 350km/h speed and turn it 1 degree. How much do they spend on the R&D of the aerodynamics in F1? That you cant see whats happening under your board doesnt mean there arent things happening. These are just stills from a video. The slow motion footage is far more interesting......

All on the shoulder of a wave not to have air in the water.
Bottom turn with fin ventilation:


Top turn, check the twist and flow away from the board:

Going up wind:

Pare " I want my simmer board back "

Also - sort the fkn rails out .... ??? .... hmmm , he mentions having certain problems / rails ...

I fanatic quad passed thru my hands a few years ago ,,,, sailed like crap ... I sanded the rails softer (mid plan shape to upfront) ... suddenly was a different board ... sometimes the concessions to onshore / test scores cost alot ....

GESTALT ..... " for me this thread is a fascinating example of how cognitive bias can affect perceptions.
at 14.12 mark says, toed asymmetric fins sacrifice "comfort and speed".
people will quote the video when it supports their view and then discount the bits that don;t fit into their ideas. even his comments about no toe get discredited as brand speak because it doesn't fit."

depends on what your looking for ..... cognitive bias .... ? still haven't worked out if Assy fronts are VAX or anti VAX ( thinking anti vax) ... there's a wealth of science on one side , then errr , a wealth of corporate money talk ....

cognitive bias is also based on on own wealth of experience - Ive been using toe and CANT since 2012 - I don't need Marc Pare to tell me they ' sacrifice speed and comfort , - 10 years tweaking / testing / comparing experience tells me not ..... !!!!

Depends how good you are also , you may look to a piece of text , and ignore 'comfort' , 'speed' , IF , you can actually generate speed , don't want armchair comfort , but want some DECISIVENESS ! and some MAGIC ..... depends .... do you want to take the 1/800 side effects corporate talk , or the 1/2500 hospitalisation ....? hmmmmmmmmmmmmmmmm , the choice (or NOT ) is yours

seabreezer said..
so far

TOE proponents

Witchcraft (before everyone !)

Nah, the very first board I made around 1985 was simply from a guide line in a magazine which had looked at Robby Naish boards and they said to toe-in the fins. Only back then I dont think it was called toe-in, I think it simply said to have a difference in distance between the front and back of 6mm or so. Its the board in the middle here:

I remember it also said it had 1cm of V in the tail but no mention it had any in the middle so we gave it 1cm from the middle back. This worked like a huge tailkick. It was a dog to get planing but was turning on a dime. Then I put a tape edge around the tail and simply poored 1cm of polyester resin to take out the V. Then it was planing very well but turning was a lot worse. So then I started planing off the resin bit by bit till I had a good balance.

What I also notice is that various fins have a slalom like thin profile, But in slalom speeds are higher and the angle of attack varies much less. In wave sailing fins need to be able to work at pretty extreme AoAs. I went through the data of many available foils and chose one that can handle a very wide range of AoA without stalling. Then you can also use smaller fins which reduce drag and improve turning and control.