These Fins are Changing the Way I Surf

Had to re-upload this video because KZbin deleted it
Over the past 10 years I've been developing these Quad fins with @mfchawaii7629 that would merge the gap between between the Thruster Fin and the Quad fin set up. The results are incredible and it has helped take my surfing to new levels.
If you want to try them out, here’s where you can find the fins:
mfchawaii.com/shop/surf/surf-...

[@sugewhitejacoby8654]

I was a lifeguard at Haleiwa Beach Park when Simon Anderson came out with that. Within weeks Saun Tomson, Buzzy, enen Mark Richards was trying out the thruster. My favorite board was a Thruster channel bottom. It was so fast

[@xyzct]

Remember the Bing Bonzer?

[@magiNING]

Hope you're recovering well, taking it easy.

[@danielhutchinson6158]

Thank you Kai. Grateful.

[@mariarohmer2374]

Very educational, thanks Kai! How am I still in awe of watching you surf? Speaks to your magic.✨

[@wilbers1970]

Not been a bitch but did this in the late 90s and you're right, it's amazing! I showed it to Bob McTavish and he said he rode his 4 fins the same. So not new but as you are the best and fastest big wave surfer, the ball is now in your court! Can't wait to see the results this year.

[@ILParr]

Simon made me a 6'2 triple glassed thruster backs in the 80's (i“m 6'5) and it went like a freaking bullet off the bottom on a late drop and could run down any one who dropped in. I had been waiting outside at Queenscliff during a QBC saturday clubbie comp and the wave of the day came through. So one of them dropped in heavily and told me f!ck off loudly so I rounded him up at the top of the wave and grabbed the nose of his board and tipped him over the falls. He went down screaming and i rode it back to the beach while his mates crapped themselves laughing. Simon was and is an absolute legend surfer and shaper and his custom boards didn't cost any more than one from the shop. Well it looks like you got the thrusters' second coming there.

[@UniqueStranger]

I swapped the back and front quad fins on a Stretch quad to get more drive. It worked having the back fins longer and the front fins shorter.

[@pamshewan9181]

Thanks for this Kai.

[@Nico_GER7]

Love it, Kai!

[@B0ARDTUBE]

Looking fwd to giving them a try! 🤙🏽

[@lavapix]

Someone at YT wished they had thought of this first. As a longtime constant quad user, I look forward to trying these one day. I do a 5 fin setup with the nubby.

[@bsmbB]

Sick can't wait to try it

[@just1voice994]

Good info from the wizard himself, thanks.

[@samuelmcmahon]

There's a lot of potential for this.

[@solomon6082]

Orcas: you’ll be hearing from my lawyer

[@homeless_snowboarder8225]

"since then it's the cluster they've used forever" is a hilarious statement 😂

[@rogerpye1865]

Very cool. I am guessing these fin sets are more nuanced than simply putting a 'normal' set of rear quads in the front and the front fins in the back, but I'm keen to reverse a set of mine to see what happens.

[@bencarr605]

Certainly will just reverse mine before drawing any conclusions. Big local swell Tuesday Wednesday so let’s see 🤙🏽

[@RaksasaMentawai]

Awesomeness 👌 Where to buy a set?

[@irvingalarcon6654]

The names of the fins CONTROLLERS MODEL 🤙🏄‍♂️🇺🇸🇵🇪

[@kentapo3379]

Kai when those new fin going be on the market?

[@thetruthseeker4454]

Ive recentlu added 2 extra fins to make 5. Added thrust and contr is great

[@js333able]

As Quads have the most variance in placement then any other fin configuration, that hugely effect how they feel underfoot. Have you found a fin placement that works best with this set up? And if so could you share that info as it is important to optimizing performance.

[@alikajohnson9250]

I want to try them

[@Campervankids]

I seen that Kelly slater was riding with this fin configuration. So that says it all

[@asieribanez361]

FCS2 allows to change front and rear fins even in the water, boxes front and rear have same deep... my fin Guru Bruce Mckee show me that if i wanted more drive, this is a nice way, he used th Formula 1 cars as an example, he asked me... where are the big tyres? Front or rear?

[@craig8638]

Will they work in any board mark? Will they work in my 6’6” Ghost? That’s basically a short board for me these days. Don’t get old.

[@hughmckendrick3018]

Isn't that what a twinzer set up is? Two larger fins back, two smaller fins front?

[@Vlapstone]

So, logically, just switch the sizes of the quads I already have? the bigger ones on the back?

[@gretchenrhodesmusic346]

wow...!

[@NCsurfer607]

What foil are the fins front and back ? That make an big difference too

[@finsdotsurf]

Right! Volume/Chord counts a lot too. Are these foils 50/50 or lifting toward/away from each other? Big differences between what you'd want at 3ft and 60ft as well. Hey try my fins out they have wings and are tuned for 2-15ft.

[@JammaLamma]

So how long until someone thought to change the fin placement in the quad setup? But seriously good job Kai although i do have to wonder how many quad shapers and lovers aren't going "why didn't I think of that?"

[@Shane-dq9tm]

Go Kai! Where can the average surfer get ‘em?

[@dkilla01]

I want em!!!!

[@AdmiralSugar]

so can I take the surf fins for the surf board and put them under a windsurf board?

[@AN-yr7nm]

You can always try :) probably for wind or kitesurf you might need bigger fins :)

[@NathanHarrison7]

Kai would know.

[@afloatfish]

Back fin profile looks like a brewer style template.. kinda like Ryan Lovelace twinzer back fin template and way bigger canards.. this setup is sixk

[@deedominus1002]

Where to buy this???

[@thejonathanrath]

How are they in 90 foot plus tho

[@yahwea]

🤙

[@chrisbrandon511]

Skeg da skeg omg it's a skeg

[@finsdotsurf]

Kai, show us the 3rd dimension of your fins! Surfers are still mostly blind to foil patterns and thickness/chord ratios. Check out what I'm up to.

[@AlexandreBianchi.]

more windsurf pleeeeeeeease

[@WhiteNacho]

Gimmicks

[@benyhuckaby7478]

Fins look sick but we both know you want a second go at that shaka

[@sailingsibongile]

More research is required on this... Because the explanation defies the laws of physics. You cannot create energy from nothing... So you cannot create thrust on a surfboard, you can only reduce drag. Also, you can... 😉... Create more lateral holding with a straighter fin set-up by moving the main holding fins aside. I suspect that you'll find that's where the strait line speed is coming from. ...a lowering of the drag. And the additional control is coming from the additional surface area, but the angles are more optimized for higher speed. This is kinda fluid dynamics 101. I suspect, however, that 'physics' is not why this is being promoted. It's the sales from all the "I want a set" and the "I can't wait to try them" people.

[@timp024]

Venturi. What is the Venturi effect in simple terms? Venturi effect - Energy Education The Venturi effect describes how the velocity of a fluid increases as the cross section of the container it flows in decreases (like when flowing through a funnel). The energy in this increased speed comes by reducing the static pressure of the fluid. Without fluid dynamics modeling, you have to be a non traditional genius to naturally understand, and Brilliant to be able to explain it. I work in Watersports, and in my opinion more complicated then Avation, with the ability to do things the same but different.

[@finsdotsurf]

REDBULL, KAI, where is the knowledge?! Best teams and tech on Earth and you're telling us the breakthrough is bigger fins in back? What airfoil patterns are worth a look in these fins, what chord/thickness ratios. You say it compresses between the fins 'like a jet', so they're generating lift aimed forward and toward the center? I've got 2nd and 3rd gen designs to learn how to create, but am working on more important stuff first that could help our surfing neighbors all over Earth. Buy some of my fins.

[@malloot9224]

This whole idea, man, it's just not vibing with the science of water. Here's the thing: the thought that a fin can actually kick in some extra thrust seems way off the mark. When you're out there, catching a wave, it's all about riding that descent - that's your real speed boost, right? Anything else you stick in the water is just gonna drag you down, slow your roll. So, the trick is to keep things as sleek as possible, just enough to steer and keep your groove. Now, when it comes to this four-fin setup, it's a cool thought. It might just be the sweet spot - enough control without killing your speed. But saying it's creating thrust? Nah, that doesn't really hold water. It's more about slicing through, staying agile, and keeping upright on those waves. Those fins? They're there to help you carve and control, not to push you forward like some kind of motor.

[@AK-ms5zk]

Like a twinzer? 🤷🏾‍♂️

[@afloatfish]

More of a twinzer in a weird way

[@jessewilkinson7613]

YOuTube should treat you more better

[@johndoe-bu7vt]

these fins look good and no doubt Kai is pushing the limits, but amount of dogma in surfing is ridiculous. like removing center fin and replacing it with two fins and claiming to reduce drag is utter bollox. and all those wild theories about the flow.... gosh.

[@dennygrant8148]

kai great waterman, physicist he is not. "Fins making funneling water like a jet" sorry buddy does not work that way. Do I think these might be great fins, yes, do they work probably. It just when pro surfers and shapers start talking physics its pretty bad. People who understand this stuff spend 10 years after high school, and do test after test to under stand what's happening. I think Kia has a GED, not a PHD from MIT

[@simoali975]

bla bla bla bla bla bla

[@byronbass1370]

Fins have not been the same for the past 40 years. Just do some research. Try read

[@mtoto17]

you do the research dork 😀

[@smurphas6119]

i mean he said ‘largely the same’ a very subjective statement that was clearly just intended to be combined with ‘that’s all about to change’ to create a hyperbole. also, it’s kai lenny. don’t embarrass yourself trying to tell one of the best big wave surfers in the world about surfing.

[@Marionetax]

@@smurphas6119as simple as that. 👏🏻

[@0warami_7oo]

Simon Anderson thruster

[@nichobee]

Try surfing like Kai Lenny