Put some on my good old 8’ low volume semi-gun… about a thumbs width in front of the fixed placement FCS.
First thing I noticed was it (the board, to be refered to as it) felt looser, just at the going straight point, or turning. I felt like it was ready to turn, but once it was turning/going down the line it flet solid.
Sad reality is, I knew what was happening, and I swear I could feel the multiple votricies that had been generated letting my trailing fin flow easier through the enhanced flow… ready and waiting to turn.
Summary after one session in decent head high peaks, kind of crumbly, but peeling. Looser, turned sharper easier. Maybe even faster…
Love to hear any others experiecnes.
Taylor
Ps. Much thanks to Mark for hooking me up… We both love space food!
Ive surfed my MVGs in everything from headhigh slop to overhead perfect Laniakea and have the same observations. Looser overall…snaps off the top are faster and tighter. Cutbacks are shorter.
I hope Mark jumps in. Long story too short: just like the little fins on a tuna before the tail, they generate vortecies… I would describe them as 5/8" deep “keels” about an inch long, two in a row. They are placed about 5/8" in front of the trailing fin. And the rest, as they say, is history. One of the theories is, re. turning - by breaking up the water ahead of the fin, it won’t “stall”/become un-effective at high angles of attack (AOA). After riding with them, I think because the water just in front of the fin is already “broken up” the fin can keep working - even though it’s turning so hard as to be rendered ineffective. I think it’s supposed to work on planes and stuff.
What a coincidence. I am trying a little experiment with using MVG’s. I have a bag of them from Mark and I want to calc the surface area of one of them and add enough of them in a couple of rows to approximate the surface area of a set of twin fins. Then surf it and see what happens.
Mark, I’d be shocked if you had not already done this. Feedback?
There’s also something similar used on wing surfaces called turbulators. Their purpose is to create a small surface disturbance at the apex of the foil, allowing the laminar flow to stay closer to the surface by keeping the induced boundary layer smaller. No turbulator equals a larger boundary layer which equals less performance.
I prefer a better fin design, rather than find secondary solutions to performance problems. Turbulence is not something I want to create.
But then again, it’s just a surfboard, and having fun is really the main objective. Try everything. Use what you like.
The way I understand it is close to what you have written, but it is not on the wing surface, it is ahead of the wing alowing the wing to perform better. Never the less - if inducing vorticies allows the fin to work better and in the end produce less overall turbulence, then it seems to follow one is better off inducing some turbulence “up front” to produce less over all. The other fact is, and, no offence, but it is a scientific fact, the generation of the vorticies will enhance the performance of the best fin design. So, keep up the quest for the best fin, and let’s enclude the MVG to the casting mold… and we’ll all be better off.
The best experience I’ve had is with the white MVGs mounted just in front of the back fin of this 7’4" Terry Chung “Fatgirl” that I bought used from Alekai Kinimaka.(Picture attached) The fins are glassed on carbon fiber stiffees
You can see the little white MVG in the attached picture.
It’s hard to imagine such a little thing making any difference but the over all effect is just alot smoother response all around.
everything seems in control and each turn seems to flow into the next. Almost like the power stream is maintained through the entire arc and weighting unweighting process of going through one turn into another.
Most of the times boards will lose it somewhere between one turn and the next almost like a dead spot.
That’s why pros and really good surfers (not me) can, milk their thrusters with little itty bit carves youcan’t really see to keep up the speed between each move. Most guys can’t do this so the moves, or turns appear jerky or staged.
The MVGs somehow keep the speed going in all positions which I guess makes it feel smoother and less jerky.
Seem like the MVGs in front of a standard rear thruster fin and some Webber CRV sides up front might be an interesting test for flow… You just don’t get any down the line drive with the CRVs but they turn crazy…
I’m running this on my 8’0"x21.25" Freeline Speed Platter (full on concaved bottom). I made a little extension on the front of the fin tab and mounted the MVGs on it so they’d be in the right spot for the board. The fin is pretty upright and speed foiled at 45/55. The board may have gone faster but I can’t remember when. I gotta put some little rail fins on it to calm it down so can snap it around better. I’ll post some photos after I take it out the next time. They seem like speed applifiers that tend to make the fin a little twitchy as the board slows down.
I want to try a couple sets on my traditonal Keel fin fish.
would the mvg disrupt the stability of a single fin longboard? I’ve often thought about how a little more speed would be nice on a longboard at certain breaks down the line (sharks, for example.) I wonder if the twitchyness at low speeds would be a problem on small fast waves though.
halcyon, did you pick up that set anywhere here in town? other availability? might be fun to try them on different boards to see how it changes the feel (single fin vs thruster, etc.)
