Author Topic: Kai Lenny BOP Fin Design  (Read 9608 times)

paddlenorcal

  • Rincon Status
  • ***
  • Posts: 194
    • View Profile
    • Email
Kai Lenny BOP Fin Design
« on: October 09, 2013, 06:19:26 PM »
Anyone know anything about this design? http://www.mauifin.com/sup/  Looks pretty crazy compared to the standard rake and shape fins it seems most racers are using...

paddlenorcal

  • Rincon Status
  • ***
  • Posts: 194
    • View Profile
    • Email
Re: Kai Lenny BOP Fin Design
« Reply #1 on: October 09, 2013, 06:20:42 PM »
They call it the "Sprint 5" I'm assuming...i cant seem to find any other source of info on its design and benefits.

supgobes

  • Rincon Status
  • ***
  • Posts: 127
    • View Profile
Re: Kai Lenny BOP Fin Design
« Reply #2 on: October 09, 2013, 06:55:43 PM »
I've been looking for info on that fin for a couple of weeks.  Thanks for finding the site.

I was asking Kai about that fin at Huntington Beach.  I asked if his board was less stable with that fin and he replied that it was more stable and that he sees all fins going in that direction.

paddlenorcal

  • Rincon Status
  • ***
  • Posts: 194
    • View Profile
    • Email
Re: Kai Lenny BOP Fin Design
« Reply #3 on: October 10, 2013, 06:11:36 AM »
Gobes, It sure seems that based on Kais buoy turns that the fin works. Then again, he could probably strap a beer can to the bottom of the board and make it work!  With the radical shape and his success, I'm surprised I haven't seen more talk about the shape. I'm considering trying to shape my own out of a larger fin I don't use anymore.  We'll see how it goes, I'm far from a  fin shaper! 

supgobes

  • Rincon Status
  • ***
  • Posts: 127
    • View Profile
Re: Kai Lenny BOP Fin Design
« Reply #4 on: October 20, 2013, 08:57:17 PM »

adamrod

  • Rincon Status
  • ***
  • Posts: 122
    • View Profile
    • Email
Re: Kai Lenny BOP Fin Design
« Reply #5 on: October 20, 2013, 11:18:25 PM »
Basically all I got from that video was that "we use a smaller fin because it has less drag". I would agree with that, don't really understand why racers use such big fins.

That said, I don't buy the crazy design. higher aspect shapes (long and skinny) have less drag than lower aspect (short and fat) (think about wings on a glider).  He claims the wider base helps it track, but I really can't imagine a few extra CM in width on the fin makes a difference in tracking on a 12 ft race board.

Fins matter on a surfboard as there is a lot of loading and speed, and it's a planing hull, so fin area is a greater percentage of whats in contact with the water, but at the relatively slow speed of a race board, I can't imagine it making a bigger difference than hull shape.

Muskoka SUP

  • Peahi Status
  • *****
  • Posts: 863
    • View Profile
Re: Kai Lenny BOP Fin Design
« Reply #6 on: October 21, 2013, 02:23:55 AM »
Basically all I got from that video was that "we use a smaller fin because it has less drag". I would agree with that, don't really understand why racers use such big fins.

That said, I don't buy the crazy design. higher aspect shapes (long and skinny) have less drag than lower aspect (short and fat) (think about wings on a glider).  He claims the wider base helps it track, but I really can't imagine a few extra CM in width on the fin makes a difference in tracking on a 12 ft race board.

Fins matter on a surfboard as there is a lot of loading and speed, and it's a planing hull, so fin area is a greater percentage of whats in contact with the water, but at the relatively slow speed of a race board, I can't imagine it making a bigger difference than hull shape.

Winning races like this years BOP and the final at Turtle Bay was all about planing a race board.  Kai not only caught the waves in, he managed the best and styliest buoy turn at the BOP ever seen...
Whether or not any of that was attributable to the new fin is arguable.  The rest is just good marketing at the right time.

It ain't over until the fat board sinks....

Area 10

  • Cortez Bank Status
  • *****
  • Posts: 4057
    • View Profile
Re: Kai Lenny BOP Fin Design
« Reply #7 on: October 21, 2013, 04:59:14 AM »
He claims the wider base helps it track, but I really can't imagine a few extra CM in width on the fin makes a difference in tracking on a 12 ft race board.
I have to disagree. Even a fairly small difference in the width of the fin at the base makes quite a difference to tracking. The problem is that it also makes the board harder to turn, and creates drag in some situations when you don't want drag.

I can see the logic of this - wide base for tacking and a minimal take on the rest of the fin as you can get away with, to increase maneuverability and decrease drag. But the video hardly inspires great confidence (did he really say that he based the fin on a Ninja throwing star???) in how thought-through and well researched the physics of the design is. But I guess the main object of the exercise for manufacturers is to think of something that is distinct from what else is out there, and then get one of their star riders to promote it, preferably with some pseudo-scientific mumbo-jumbo to impress the easily impressed, and watch the cash roll in...

But at least it is a new and bold design, and I think that if you can do without your fin providing much in the way of stability at all, then this would be interesting to try.

Unfortunately however, the three activities I do most are: surf SUP, downwinding, and flat water paddling in heavily weed-ridden areas. For downwinding you generally need a fairly small base area (or an extreme solution like the Aercor) and often some depth to the fin. For surfing you are best with, unsurprisingly, a fin that looks like a regular surf fin. And for paddling very weedy areas you need a very gentle slope at the front base so no weed will catch. But this fin design meets none of those criteria, so is not much use to me.

But maybe if you have the balance of a cat and mainly do BOP-style or pure flatwater racing in clean water, this might be interesting to try.

Muskoka SUP

  • Peahi Status
  • *****
  • Posts: 863
    • View Profile
Re: Kai Lenny BOP Fin Design
« Reply #8 on: October 21, 2013, 07:44:41 AM »
He claims the wider base helps it track, but I really can't imagine a few extra CM in width on the fin makes a difference in tracking on a 12 ft race board.

Unfortunately however, the three activities I do most are: surf SUP, downwinding, and flat water paddling in heavily weed-ridden areas. For downwinding you generally need a fairly small base area (or an extreme solution like the Aercor) and often some depth to the fin. For surfing you are best with, unsurprisingly, a fin that looks like a regular surf fin. And for paddling very weedy areas you need a very gentle slope at the front base so no weed will catch. But this fin design meets none of those criteria, so is not much use to me.


Area 10 - The Aercore does not pick up many weeds.....and it's a pretty fast solution for a more downwind specific board, even when paddling it in flat water.  Just don't expect a lot of stability from it at displacement speeds.
It really is a cool solution for some boards downwinding  idiosyncrasies. (like the first two iterations of the Naish Glide.)

Of course if you have one - or more  ;D , then you already know this.   

You're right about the contribution of the base of the fin.  I'm surprised that Larry A hasn't jumped into this conversation.   The Ninja tells all.

It ain't over until the fat board sinks....

Larry Allison

  • Peahi Status
  • *****
  • Posts: 933
    • View Profile
    • https://www.facebook.com/larry.w.allison
    • Email
Re: Kai Lenny BOP Fin Design
« Reply #9 on: October 21, 2013, 08:02:05 AM »
He claims the wider base helps it track, but I really can't imagine a few extra CM in width on the fin makes a difference in tracking on a 12 ft race board.

Unfortunately however, the three activities I do most are: surf SUP, downwinding, and flat water paddling in heavily weed-ridden areas. For downwinding you generally need a fairly small base area (or an extreme solution like the Aercor) and often some depth to the fin. For surfing you are best with, unsurprisingly, a fin that looks like a regular surf fin. And for paddling very weedy areas you need a very gentle slope at the front base so no weed will catch. But this fin design meets none of those criteria, so is not much use to me.


Area 10 - The Aercore does not pick up many weeds.....and it's a pretty fast solution for a more downwind specific board, even when paddling it in flat water.  Just don't expect a lot of stability from it at displacement speeds.
It really is a cool solution for some boards downwinding  idiosyncrasies. (like the first two iterations of the Naish Glide.)

Of course if you have one - or more  ;D , then you already know this.  

You're right about the contribution of the base of the fin.  I'm surprised that Larry A hasn't jumped into this conversation.   The Ninja tells all.



Hi my friend, I have been watching this with alittle laughter. Kai is a amazing rider and can ride anything. The fin is pretty cleaver concept, a combo of a pointer fin for pivot and wide base for tracking. But a very specialized fin not for most. Cool the BUZZ created love that.

I have done something similar in concept from a different approach for a larger range of paddlers, 2 weeks before BOP and Chuck Glen came in first at BOP using this 5" tall and 9" long based Race fin.
« Last Edit: October 21, 2013, 08:09:35 AM by ProBox-Larry »
Allison Race Fins

paddlestandingup

  • Rincon Status
  • ***
  • Posts: 172
    • View Profile
    • Email
Re: Kai Lenny BOP Fin Design
« Reply #10 on: October 21, 2013, 03:39:45 PM »
I'm with you Area10.  I was mildly interested until I heard something about a throwing star.  Either way, I wouldn't go near a fin like that, Kai and I don't really have a lot in common!

sup_surf_giant

  • Teahupoo Status
  • ******
  • Posts: 1630
    • View Profile
Re: Kai Lenny BOP Fin Design
« Reply #11 on: October 21, 2013, 04:56:38 PM »
I came in 17th out of 28 in my class at BOP.

How did I accomplish this amazing feat?

Why my Danny Ching race fin of course!  ::)
Taller than most, shorter than others.

Fishman

  • Peahi Status
  • *****
  • Posts: 519
    • View Profile
    • Email
Re: Kai Lenny BOP Fin Design
« Reply #12 on: October 21, 2013, 04:57:50 PM »
Kai's 5" race fin looks a good bit similar to Exocet's SUP surf trailer fin.

I wanted to try Exocet's fin as a single fin just to see how that would surf. it really looks like it could rip and hold :-\
(cant find a picture of it right now >:()
SupSurfMachine 9'9" longboard
SupSurfMachine  8'2" funboard

SUPerSwede

  • Rincon Status
  • ***
  • Posts: 214
    • View Profile
Re: Kai Lenny BOP Fin Design
« Reply #13 on: October 31, 2013, 08:19:43 AM »
That's pretty funny. I've been using a similar concept in my Nalu 10'10 with two fins in line. Right now I'm using two cheap K4 fins, one 14cm in front of a 10cm one. It gives acceptable tracking in a straight line yet enables me to turn tightly and even pull off slow wave 360s in minute waves and shallow water. I didn't realize how competitive I must now be :-) :-) :-)

NXLVL

  • Sunset Status
  • ****
  • Posts: 473
    • View Profile
    • Email
Re: Kai Lenny BOP Fin Design
« Reply #14 on: November 04, 2013, 03:55:48 PM »
my stab @ this design...... first fin design ever. cut out from a 10.5" down to 4.5" by 7.5"
my take....my fin tracks like sh*t! stability...not an issue. drag? substantially less than if I left it 10.5" DUH!!! bouy turns....freakin awesome, turns like a "dime mower." conditions... 4.5 miles inside, slight upwind & up current, half a foot of chop. how different is Larrys fin to sprint5, not much. im sure kai is using a stroke technique, such as a C or J stroke along with his ability to make this fin look like a pair of "Jordans!" just because you bought a pair, does not mean you can DUNK! good luck on anyone who purchases the "Sprint5!" my fin sucks & im sure Larry is laughin @ me. chill.....would love for you to get back into racing just for your input.
« Last Edit: November 04, 2013, 04:00:07 PM by NXLVL »

 


SimplePortal 2.3.7 © 2008-2024, SimplePortal