Author Topic: The ventral fin from Larry W. Allison  (Read 24021 times)

Henrik F

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The ventral fin from Larry W. Allison
« on: January 03, 2013, 05:12:46 AM »
I've been out today trying the ventral fin from Sup Race Fins, Larry W. Allison. In a bit choppy conditions. First I paddled without the ventral and just a Ninja. Then with the ventral fin and the board was a lot more stable. Not tippy at all :)
Then I paddled into the more calm conditions in the marina. I like the Ninja because it allows me to take more strokes per side than the fin that comes with the board. But with the ventral fin attached... It felt like I could have gone on and on. This is a serious improvement. Probably to any board that you use in flatwater or chops, whitecaps... Brilliant!

Henrik F

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raf

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Re: The ventral fin from Larry W. Allison
« Reply #1 on: January 03, 2013, 05:36:47 AM »
Sweet!  Looks organic.  There's a reason millions of years of evolution have put fins up there on fishes.  It must work good.

bbqSUPer

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Re: The ventral fin from Larry W. Allison
« Reply #2 on: January 03, 2013, 01:32:51 PM »
How did you come up with where to place it?

Henrik F

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Re: The ventral fin from Larry W. Allison
« Reply #3 on: January 03, 2013, 02:00:49 PM »
How did you come up with where to place it?

I spoke to Larry and had to do some measuring from where I usually stand on the board.

Henrik F
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mik911

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Re: The ventral fin from Larry W. Allison
« Reply #4 on: January 03, 2013, 10:52:32 PM »
So I assume you need to have a shop put in a finbox?
Mike

Ron House Coastal Cruiser 12'6"
Hoe Nalu surf sup  10'6"
BARK 14' custom carbon SUP
Fanatic Fly Race 12'6" carbon SUP
BARK 14' prone custom paddleboard
BARK 12' prone Surftech paddleboard
Longboards: Harbour, Becker, Local Motion
Kneeboards: Cleary 5'10"
Handboard: Brownfish

Henrik F

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Re: The ventral fin from Larry W. Allison
« Reply #5 on: January 03, 2013, 11:09:16 PM »
So I assume you need to have a shop put in a finbox?

In my case, ABSOLUTELY :) But I think that people who are more familiar with reparing boards and such could do it.

Henrik F
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upwinder

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Re: The ventral fin from Larry W. Allison
« Reply #6 on: January 04, 2013, 12:04:21 AM »
Hey Henrik - nice work. Here's a couple of pics of my ventral/PCF setup* on my 2010 Naish 17'









I've taken the steering mech off and in flat water I can comfortably stand well forward of the handle, giving me about 16' of waterline**. It changes the character of the board significantly...it's a much more viable distance cruiser/trainer now with several 15-20+ km runs completed this season. The ventral stabilises things very well in side chop and when I'm standing up forward. It improves tracking enormously, yet when I take a couple of steps back to turn it the ventral lifts out of the way enough not to interfere. I originally bought the ventral to put in the yellow 14' race board behind it but I sold that board and had the forward fin box fitted in the 17 instead, glad I did.  Colour me happy  ;D

(*the ventral box is fitted 20" forward of the board's balance point, per Larry's instructions...right where it should be)

(**for some reason my 17 is a good bit flatter in the rocker line than other Naish 17s I've seen...this is a bonus for my purposes, possibly limits its potential in big open water but I don't care about that)



« Last Edit: January 04, 2013, 12:14:08 AM by upwinder »
In theory, there should be no difference between theory and practice, but in practice, there is...
Sheldon Brown

Henrik F

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Re: The ventral fin from Larry W. Allison
« Reply #7 on: January 04, 2013, 02:41:15 AM »
Hey Henrik - nice work. Here's a couple of pics of my ventral/PCF setup* on my 2010 Naish 17'









I've taken the steering mech off and in flat water I can comfortably stand well forward of the handle, giving me about 16' of waterline**. It changes the character of the board significantly...it's a much more viable distance cruiser/trainer now with several 15-20+ km runs completed this season. The ventral stabilises things very well in side chop and when I'm standing up forward. It improves tracking enormously, yet when I take a couple of steps back to turn it the ventral lifts out of the way enough not to interfere. I originally bought the ventral to put in the yellow 14' race board behind it but I sold that board and had the forward fin box fitted in the 17 instead, glad I did.  Colour me happy  ;D

(*the ventral box is fitted 20" forward of the board's balance point, per Larry's instructions...right where it should be)

(**for some reason my 17 is a good bit flatter in the rocker line than other Naish 17s I've seen...this is a bonus for my purposes, possibly limits its potential in big open water but I don't care about that)





That is a beautiful job you've done there! And I went just under 20" too when I had the fin installed. I will have to wait for a bit more decent weather conditions before putting on kms. It is seriously cold here in Sweden now. The ice has been melting for a while but it will surely be back :(

Henrik F
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upwinder

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Re: The ventral fin from Larry W. Allison
« Reply #8 on: January 04, 2013, 06:00:03 AM »

. I will have to wait for a bit more decent weather conditions before putting on kms. It is seriously cold here in Sweden now. The ice has been melting for a while but it will surely be back :(

Henrik F

Man, that looks cold. More power to you for getting out there

(If it helps warm you up some, a group of about 10 of us down here enjoyed an awesome downwinder this morning in 40C heat... No wetsuits today  ;D )
In theory, there should be no difference between theory and practice, but in practice, there is...
Sheldon Brown

Henrik F

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Re: The ventral fin from Larry W. Allison
« Reply #9 on: January 04, 2013, 06:13:30 AM »

. I will have to wait for a bit more decent weather conditions before putting on kms. It is seriously cold here in Sweden now. The ice has been melting for a while but it will surely be back :(

Henrik F

Man, that looks cold. More power to you for getting out there

(If it helps warm you up some, a group of about 10 of us down here enjoyed an awesome downwinder this morning in 40C heat... No wetsuits today  ;D )

I got really warm now. Of envy  :D

Henrik F
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surf monkey

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Re: The ventral fin from Larry W. Allison
« Reply #10 on: January 04, 2013, 10:20:04 AM »
I think the fin is a cool idea but how is it in a down winder? I understand the board is more stable but will it cause the board to start tracking when your at speed on the bumps or keep the board from releasing when trying to get the bump?

So with the forward fin in could you go with a smaller rear fin to reduce the drag? or would that make a difference?

Thanks

jd

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Re: The ventral fin from Larry W. Allison
« Reply #11 on: January 04, 2013, 11:28:41 AM »
I did one of the first ones of these with Larry.  I was one of his guinea pigs.   :P

This is from 2008.  How time flies.






westbeach

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Re: The ventral fin from Larry W. Allison
« Reply #12 on: January 04, 2013, 01:09:33 PM »
Looks like it's time to get in touch with Larry again. ;) I am considering adding this to my 14' M&M. Thanks for feedback Henrik!

Henrik F

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Re: The ventral fin from Larry W. Allison
« Reply #13 on: January 04, 2013, 01:36:58 PM »
Looks like it's time to get in touch with Larry again. ;) I am considering adding this to my 14' M&M. Thanks for feedback Henrik!

No problem!

Henrik F
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corlot

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Re: The ventral fin from Larry W. Allison
« Reply #14 on: January 04, 2013, 03:06:10 PM »



     
   
"Re: The ventral fin from Larry W. Allison
Reply #12 on: Today at 04:09:33 PM    
Looks like it's time to get in touch with Larry again.  I am considering adding this to my 14' M&M. "

14 M&M?! When did that happen?