I put this together over the weekend , it gives a good insight to Sup fins and explains the JP straight fin theory.
Some really cool under water fin shots from my new Sony action cam mounted in the rear box, Bit of a longer video than I normally post but there was heaps that needed to go in , plus it has a pretty cool ending.
Thanks Rob. That was great learning. Didn't realise that so much air was under the board. I had many a cavitation back in the early sailboard days. Constantly trying different fins back then. I have changed my rear fin but will now get some good side biters. cheers
Thanks Piros
, and glad I went for futures boxes sides and centre thruster setup on my DTM custom, leaving nothing open for the air bubbles, guess the five fin crew will have to get the duct tape out
Piros, one question.
With the 0 degree cant and toe, have you tried center fins in the sides?
Like you say it goes against everything I habe ever learnt but I'd love to try it to see how it feels.
Hey Piros,
The Sony is so much better than the NO GO, I have had little or no fogging at all so far.
I agree CMC,
I have a friend thats looking for an 8'6 does anyone have an 8'6 JP demo in Melbourne would love to see how they go?
Phill
, and glad I went for futures boxes sides and centre thruster setup on my DTM custom, leaving nothing open for the air bubbles, guess the five fin crew will have to get the duct tape out
nice video - any fin-set up is a compromise - full straight fins will be fast at the expense of hold, responsiveness, tightness of turns etc....
I'm not saying it doesn't work on this board, sounds like it does, but the fact that it works for Keahi who weighs 60kg?!? doesn't mean it will work the same for a guy who weighs 80kg.....(provided board will float a 80kg guy)
If you want to tune your board we should all have these: www.4wfs.com - he's based in Oz now.
I've done heaps of testing with 4wfs on kiteboards and some SUP's. Any change you make, affects board in positive and negative ways.
Futures and FCS will tell you all you need to do is change the fin, what I learned was that each board and fin also required a different toe, fore/aft placement and sometimes splay/cant as well - but heeding Piros call and getting a quiver of fins is a good start.
Fact is, there are no absolutes, every board is different and every rider will prefer a different set-up.
Very informative Rob ,great vid. we have been tryinging the MR's {twins} with foiled insides and and a slater back fin , heaps of drive and not as much drag , love to try the no toe ,no cant, good discovery.
so yes it does still work for the larger units. I'll check out those fins always willing to try something new.
Well Spoken Piros very knowledgeable I haven't been on my SUP since May on Namotu. Woodys making me another 8'5" and I'm 95kg I think I'll be giving futures a go.
You're sony camera gives out a clear picture stoked. I've sent all my GoPro gear back for the full refund.
Well done Piros,must agree fin combos can make an amazing change in board performance.I'm sure the theory of straight rear fins would create some animated read pissed debate,with alot of surfers.Your explanation examples sure gets you thinking.Many thanks for the time an effort put into your vid.
i saw marty's custom 8' jp and it had cant, not sure about toe. mind you it has very pulled in tail.
i'm a bit sceptical about the turning part myself. most of the talk has been about how fast they go only. happy to be wrong about that thou
i can work with the no cant part. sometimes at high speed it is hard to keep the tail and rail in the water.
i reckon cant with no toe wouldn't lift. the two angles of the side fins create the lift
i would give a fin setup with toe only ago for some turning power.
good subject.
funny i posted that song's vid on the lb forum after a bit of cheek last week
cheers
One of the best article on the toe of side fins I have read is the one made by Bouke, the shaper of Witchcraft, but I cannot find it anymore.
Basically, he used the 4way fin system to change the toe on the water on sailboards, and examined the wake at speed.
He found out the the water was not getting out the rear in a straight line, but more or less on the side (more with V, less with a rear concave), less at speed, more at low speed, etc...
So some toe was actually necessary to have the fins aligned with the water flow to minimize drag, contrary to popular opinion. A fin with no tow will induce drag and turbulence. Also water was less displaced by the hull at the tip of the fin, so the toe should be less at the tip than at the base.
Here was I could still find but not detailed enoughhttp://www.windsurfermag.com/magazine/twisted-windsurfing-fin-witchcraft-flow-optimised-multifin-thruster/?params=Mjd8MzY3fDA=
The lift is the misunderstood part of fins......
It is not vertical lift, it is outwards towards the rail lift. Imagine an air plane wing, it lifts upwards. Now turn it on its side like downwards on the plane.
High pressure one side, low pressure the other. It's what holds the tail of the board into the wave while your body and outwards pressure is pushing the other direction.
The fin toe in is generally positioned where it is as a zero degree lift line, ie when travelling straight the fin is in a neutral position and does not pull outwards and stick.
That is why many inside foiled fins which create more lift are corrected on the tabs to be sitting on a more accurate zero lift line per the design of the fin. This adds toe in to the fin. ie more towards the nose.
Cant is a function of creating a fin that remains at less than vertical for longer, it may also create some upward lift in conjunction with the outward life created by the fin but we are not on Tow boards or kiting or sailing at 80km/h for that to be point. It also allows release off the top.
As I say, this design sure has me interested. I really want to try it, I'd love to see how it feels and be proven wrong. I'd love to see if you need to use smaller fins to compensate for the stiffness added by no toe or cant.
Only a blind man walks around without seeing I always say. This could be how it's meant to be....
Really nice vid and the boards look awesome.
What about the angle of the boxxes of the widebodys?
Excellent vid Rob. and loved your bug at the end. As I always say, ' you can't have enough fins' I have been experimenting a lot with fins of late and I am loving the results.
ps from earlier post. i've checked out the jp range- bloody good looking sup shapes
Interesting topic. I was always lead to believe and of the belief that fin shape & position complements the plan shape of the board with whatever the wave type.
It'd be good to see this a subject in a Magazine with input from shapers, as commonly occurs in short board magazines.
Just love the fact the vid has stimulated debate. This is all part of the evolution of SUP's and as history has shown, the established rules are not always right. For my part, I still think the board shape has a huge influence on what fin setup works best. Also, what works for me, may not work for the next person, as there are so many variables involved. Without labouring the point, a few that come straight to mind: board dimesions(Length, width, volume, profile, rail shape), rider skill, surfing style, weight of surfer, body type/build, shape of wave etc, etc..... Plus, can we have our cake and eat it too. By that I mean pure down the line speed usually comes at the expense of turnability, not sure the setup in the vid has all the bases covered in this regard?
Yoooohoooo this video has had over 2500 plays and over 1500 downloads in 17 countries in the last 60 hours. The power of Seabreeze....Rock on Laurie
great vid
