Forums > Stand Up Paddle   Board Talk & Reviews

JP Fin theory Video

Reply
Created by Piros > 9 months ago, 23 Oct 2012
Piros
QLD, 6996 posts
23 Oct 2012 8:31PM
Thumbs Up

This gives a good insight to Sup fins and explains the JP straight fin theory.



Jeroensurf
915 posts
23 Oct 2012 7:25PM
Thumbs Up

Very nice vid!
Only comment:
Also with windsurfing the straight boxxes are a point of lots of discussions so that isnt really argument.
I tested dozzens of boards but never felt the difference between boards with or without toe, but like you pointed out an upgrade on fins makes a huge difference.

Piros
QLD, 6996 posts
3 Nov 2012 6:11PM
Thumbs Up

This vid has now been downloaded in 81 countries including some dude in Pakistan .I'm in the process of putting part 2 together after all the great feedback.

This is the short version from the Sony Action Cam...


Marvin
WA, 725 posts
11 Dec 2012 7:17AM
Thumbs Up

I would be interested to see the same video shot on a board with toe in - as a 'control' to this video.

Such a video should show some bubble turbulence when the toe in board is being paddled in a straight line, given that toe in creates significant drag.

On the same topic, I found this an interesting read on fin theory, that shows some 'science' on the topic, in terms of drawings showing why toe in creates drag:

patents.google.com/patent/US20080311806

It suggests to me that with the modern 'inside foil technology' (IFT) for the side bites - as comes with the FCS M5 etc - that less toe in might not be a bad thing. I note these IFT style fins are somewhat similar in plan form to the 'invention' in the attached, having the trailing edge of the fin at an apparent positive angle of attack as compared to the leading edge. The attached says that this type of design is best placed parallel to the centre line of the board.

Supmaori
746 posts
17 Oct 2013 5:00PM
Thumbs Up

Great video..I've jus purchased the fanatic all wave 8'6..what fins would riders suggest to give me the best performance and should I go with 9's in the front and a 7 in the back as mentioned on the video?
Cheers any advice or help appreciated.

weiry
QLD, 5396 posts
17 Oct 2013 10:38PM
Thumbs Up

great video

hey Piros.. little tip for part two vid
use a better beer can

KiwiSupGreg
38 posts
18 Oct 2013 3:14AM
Thumbs Up

SupMaori, you had the new board out yet? Interested on your thoughts.

Supmaori
746 posts
18 Oct 2013 8:34AM
Thumbs Up

Hey Greg..yip iv had it out twice in small clean slow surf and once a a choppy onshore day . Id like to get into some pumpy waves but still waiting for that nice sell to hurry up. What i can say is similar to comments on my other post about the allwave that othe riders have left...super stable..even on the ugly day i was out ..and on the small days it was easy to catch waves and turns well...but as i said will have to wait for the pumpy day to get a better idea of performance. The rails are more boxy than im used to ..thin and tapered towards the tail which i like...but more thick up to the nose.
I liked it so far but im going to change the fins to something like i the video above. Other posts have said that this will really make a big difference to overall performance.
Im 6ft and 90kgs and my other board is a SA 9ft 130L 32' wide..so i want the allwave for more surfability..will keep ya posted.
cheers

ghost4man
408 posts
18 Oct 2013 9:13AM
Thumbs Up

Am trying to work out what the videos are actually trying to show. Without the benefit of a control as was previously suggested or some sort of comparison point then the videos themselves are somewhat empty although they are very good in quality and clearly do point to what is going on under the board which is something that we would never see.

Ciao

Kami
1566 posts
18 Oct 2013 4:38PM
Thumbs Up

As a H2 addicted to speeding down the line the long wall on my shortboard , I did try the FCS H2 Large ones on my 7'6"/28.5" custom made and I will not do again, the extra cant and tilt make it too loose and low instead of magnified the speed and loose my SUPboard as it did on my shortboard.
The reason is in the extra toe and cant of this H2 FCS fin which is the only FCS fin to get those adjustements cant and toe , (TC Aqualine got cant only )
So PIROS is right , the extra area around fins does'nt need extra lift providing by cant and toe, so get fins square ( or beer) to planshape of any wide board.
Personally I like to go more narrow tail on my 28" width pulled back type of 7' SUP board as much as I can afford staying stand up paddling with balance in most surfable conditions , this make me think to still put some cant and toe on my next board.
I just find to use wide base fin as the TC White line which have no tip and no IFT as well because these wide base fins making shorter the distance between the pressure's back foot and the rail/planning area/fins.

Mahanumah
VIC, 336 posts
19 Oct 2013 9:21AM
Thumbs Up

Hey Piros

Great vid. Really shows some good information.

I have one question though... As a beginner (i.e. I can ride waves but not very skilled with the turns... Yet), how much difference would I notice with glass fins over the plastics?

Currently riding a Hokua 9'10"

Thanks mate

Slab
1101 posts
19 Oct 2013 6:46AM
Thumbs Up

Select to expand quote
Mahanumah said..

Hey Piros

Great vid. Really shows some good information.

I have one question though... As a beginner (i.e. I can ride waves but not very skilled with the turns... Yet), how much difference would I notice with glass fins over the plastics?

Currently riding a Hokua 9'10"

Thanks mate


As a total beginner I doubt you will notice a huge amount as you have little to compare with.....but after a bit of time, once you start changing fins you will notice. Fins can really change a way a board surfs. Depending on what you want to feel you can alter the speed, drive, turning ability and grip. When I prone surfed I loved changing single fins on my longboards...made a huge difference and can bring a board alive. On a SUP...well...the biggest change I have noticed is changing from a thruster to a quad set up.......fast and loose.....far more fun on smaller waves.

Mahanumah
VIC, 336 posts
19 Oct 2013 10:03AM
Thumbs Up

Thanks Slab

Don't want to spend heaps on fins only to not feel anything different.

Having said that the Hokua allows me to change to a quad. Have heard lots of guys doing this with a nubster in the centre. Is this worth it at my level?

I already have a quad set (plastics unfortunately) that I can use but don't have the nubster.

Ultimately looking for something to assist with the turns and help me get past the closeouts

MickMc
VIC, 452 posts
19 Oct 2013 1:52PM
Thumbs Up

Very interesting video thanks Piros. As you suggested I put a camera in place of the back fin but it seems to slow down the board heaps. Am now experimenting with putting cameras in all fin boxes. I have found that if you put the Sony slimcam in as your main back fin and the a couple of old kodak disposables in as the sidebites I get the slowest result. Next up I am going to mount my mobile phone on a tripod and shove it in the back centre finbox as a classic old mal style single fin. Yeeew!

log man
VIC, 8289 posts
19 Oct 2013 3:04PM
Thumbs Up

AAAhhhhhhh fins..............!!!!...?????.....Nice vid piros but a nylon fin isn't necessarily a "bad" fin. I mean why is bending from the base a bad thing? There is so much voodoo in the fin area, it hard to know what to think. There seems to be lots and lots of guys like Mr. Close marketing fins......that have no more scientific basis to them other than Mr. Close recommends them.........well great....but.

Kami
1566 posts
19 Oct 2013 4:19PM
Thumbs Up


Like said Pyros ,Fins position is so important and square to planning area which means No toe and No cant is a good solution .
On this 8'8" board I had an 8" cutaway as a back fin and GL on the side. The trouble is I fitted a 10 percent toe on side fin with a bit of cant, normally I'm used to put 5% on shortboard. So this 10% was an idiot experimentation
To prove please watch the spray wake from the outside fin GL under my 8'8" board : so much sprays oblic to my track breaking my speed! spays sent by the excessive toe wich proves what parallel and square is much better on these wide board like SUP are

Slab
1101 posts
19 Oct 2013 5:04PM
Thumbs Up

Select to expand quote
Mahanumah said..

Thanks Slab

Don't want to spend heaps on fins only to not feel anything different.

Having said that the Hokua allows me to change to a quad. Have heard lots of guys doing this with a nubster in the centre. Is this worth it at my level?

I already have a quad set (plastics unfortunately) that I can use but don't have the nubster.

Ultimately looking for something to assist with the turns and help me get past the closeouts


If you are starting out I would stick with your cheaper fins for now...just spend time getting used to the board and how it surfs. When you've had a few months on it and getting comfortable then splash out. Never used a nubster myself.....I reckon if you are surfing quality waves then good fins are more noticeable. However. if you are riding junk mostly like me it is more about the fin set up (twinny, quads, thruster) which makes a difference. Generaly,, quads are good for smaller stuff where a bit of speed and looseness helps but thrusters shine on the bigger stuff...saying that....some ride quads on really big stuff. So many variables to be honest and the board shape makes a massive difference of course.

IN short...don't get too hung up on buying new fins at the start...keep your cash until you have got to grips with the board...then go for it and by then you might have a better idea of how you want to set up the board. Having two sets of plastic fins gives you a couple of options to play with.

colas
5065 posts
19 Oct 2013 11:52PM
Thumbs Up

On the subject of "Fins 101":
- cheap plastic fins that bend a lot should be changed for something more rigid, such as cheap rigid plastic fins :-)
- use a thruster configuration, better while learning. More control in turns, especially in the transition between turns
- fins cut are quite dangerous. sand the trailing edge & tip so that it is blunt, or better use fins with rubber edges like the proteck. Note that the cheap flexible plastic fins are often quite sharp and dangerous.

On the subject of toe-in: beware of oversimplification:
- a board in the trim line moves somewhat in diagonal relative to water, not in a straight line
- water does not come straight out of the tail. Depending on the rider weight pushing on the tail and the hull (concaves, V) & tail shape the water flow goes out also a bit towards the sides. A toe in angle of zero does not mean that the fin will be parallel to the water flow, and the tie in angle depends a lot of the board shape and the speed of the wave.

Slab
1101 posts
20 Oct 2013 12:33AM
Thumbs Up

Select to expand quote
colas said..

Note that the cheap flexible plastic fins are often quite sharp and dangerous.



Very true!



Subscribe
Reply

Forums > Stand Up Paddle   Board Talk & Reviews


"JP Fin theory Video" started by Piros