bubbas said..






I think KTs own boards, as well as the other team tiders boards, have toe in. At least all the quatro custom boards I have seen have some toe in, a little more than 1 degree. Boxes on production boards straight. I dont know why the difference, maybe they dont thrust cobra?

Bouke-Witchcraft said..




Well first of all, in spite of what your professor says, CFD nowadays is ahead of towing tank testing, which is far from the real full size stuff out at sea and as a result, test results are not reliable. Nowadays you can set the sea state, wave heighth and length and period, even various through eachother, like you can have out at sea. The guy who did this CFD research for me in 2015 got a super high grade for his work and he now runs a naval architecture design agency in France with 25 engineers and experts under him, pretty clever guy. And I know quite a few more experts in this field, students on internships and their professors, former interns plus a few of my customers have high positions in marine research institutes. Nowadays, many things are developed even just using CFD including wind turbines and airplanes. Simply as it is more accurate.
As for practice testing, in 2005 I had a few boards with the 4wfs, which allows you to turn the fins within a minute. Within a day testing in clean light wind conditions we figured out that about 2? toe-in was not only turning better, it was also faster.
Then, there are those who have gone from one day using paralel fins to my pre-twisted fins the day after. "Amazing" is what the last one said, I can give you his phone nr if you want.

But is it that hard to understand what happens under a board? When you were a kid, didn?t you jump in puddles and the water would fly everywhere? Now if you would let a board float in a pool and you would land vertically on it? All the same thing, the water wants to escape the pressure we apply on it, just when we are planing, there is a big forward component in the movement but there still is a sidewards component as well. And anyone can imagine that if you are 1m under water the water is not pushed away anymore. When in 2007 I had a board in the test of Boards magazine, I explained their head tester Ian Leonard why a board needs toe-in, he figured out right away that fins would actually needed to be twisted as well. He promised me to keep it to himself.

Then if you are a fan boy of this or that shaper since many years, I can understand that it may be hard to realise you were wrong and for some people this may lead going into denial even if the facts are staring right at them. For sure there is a name in psychology for this phenomenon. From your forum name I figure you are a german from Hamburg? I just had a long time customer from Hamburg in today picking up his new flex tail. And we were chatting about all the fin designs I had over the years and he said the first red and black pre twisted fins in 2010 were big leap forward, these RTM fins were just fragile when hitting bottom.
This was a prototype flex tail with those fins. This one had adjustable flex through airpressure but it was too hard to keep the airchambers sealed. Some ideas are good in theory but it should also be practically doable and durable.

Bouke-Witchcraft said..




Well first of all, in spite of what your professor says, CFD nowadays is ahead of towing tank testing, which is far from the real full size stuff out at sea and as a result, test results are not reliable. Nowadays you can set the sea state, wave heighth and length and period, even various through eachother, like you can have out at sea. The guy who did this CFD research for me in 2015 got a super high grade for his work and he now runs a naval architecture design agency in France with 25 engineers and experts under him, pretty clever guy. And I know quite a few more experts in this field, students on internships and their professors, former interns plus a few of my customers have high positions in marine research institutes. Nowadays, many things are developed even just using CFD including wind turbines and airplanes. Simply as it is more accurate.
As for practice testing, in 2005 I had a few boards with the 4wfs, which allows you to turn the fins within a minute. Within a day testing in clean light wind conditions we figured out that about 2? toe-in was not only turning better, it was also faster.
Then, there are those who have gone from one day using paralel fins to my pre-twisted fins the day after. "Amazing" is what the last one said, I can give you his phone nr if you want.

But is it that hard to understand what happens under a board? When you were a kid, didn?t you jump in puddles and the water would fly everywhere? Now if you would let a board float in a pool and you would land vertically on it? All the same thing, the water wants to escape the pressure we apply on it, just when we are planing, there is a big forward component in the movement but there still is a sidewards component as well. And anyone can imagine that if you are 1m under water the water is not pushed away anymore. When in 2007 I had a board in the test of Boards magazine, I explained their head tester Ian Leonard why a board needs toe-in, he figured out right away that fins would actually needed to be twisted as well. He promised me to keep it to himself.

Then if you are a fan boy of this or that shaper since many years, I can understand that it may be hard to realise you were wrong and for some people this may lead going into denial even if the facts are staring right at them. For sure there is a name in psychology for this phenomenon. From your forum name I figure you are a german from Hamburg? I just had a long time customer from Hamburg in today picking up his new flex tail. And we were chatting about all the fin designs I had over the years and he said the first red and black pre twisted fins in 2010 were big leap forward, these RTM fins were just fragile when hitting bottom.
This was a prototype flex tail with those fins. This one had adjustable flex through airpressure but it was too hard to keep the airchambers sealed. Some ideas are good in theory but it should also be practically doable and durable.

RuaraidhK257 said..




Forgive me bouke, but the bit I struggle with here about your bigger front fins x medium back fin and your flextails etc is this: why has nobody else thought of it? You're so insistent that your way is the best, that everybody who tries it is blown away, so how come word hasn't reached KT's ears? How come braw, Levi etc and all the worlds best sailors haven't tried your concepts and been blown away by them?? I'm not saying you're wrong, because I'm no expert whereas you seem to at least do a good job of sounding like one, but it just seems to me to be the height of arrogance to sit there and say, "I'm right, everybody else is wrong and/or deluded".

RuaraidhK257 said..






Forgive me bouke, but the bit I struggle with here about your bigger front fins x medium back fin and your flextails etc is this: why has nobody else thought of it? You're so insistent that your way is the best, that everybody who tries it is blown away, so how come word hasn't reached KT's ears? How come braw, Levi etc and all the worlds best sailors haven't tried your concepts and been blown away by them?? I'm not saying you're wrong, because I'm no expert whereas you seem to at least do a good job of sounding like one, but it just seems to me to be the height of arrogance to sit there and say, "I'm right, everybody else is wrong and/or deluded".

Grantmac said..
I believe Ola at Simmer does toe in on their production boards. He also posts (or did previously) on the UK forum.

I own a Simmer Quantum with around 1 degree of toe and the board is fast for a waveboard but still very turny. I've gone to a set of asymmetrical K4 fronts with another degree of toe and speed hasn't suffered one bit plus it grips in turns even better.

Running large (12cm) 2 degree Ezzys on the front of my Quatro is a setup I've used in marginal conditions with a lot of success. Again loads of drive out of turns without taking speed hit. I'd like to try it with some smaller rears to see how surfy it could be. The rear fin boxes are quite far back and I tend to prefer fairly upright fins.