Hi, I was hoping that you guys with your extensive amount of board knowledge could give me an opinion on this thought that I had about quads and pivot. Its well known that quads tend to pivot less than thrusters, and that it seems to be an accepted drawback of quads. I’m not all that bothered by it, but I have been on a bit of a mission tinkering with fins to try to squeeze more pivot out of the board. A good shaper told me that quads will always have different attributes to a thruster, and I agree with him totally. I still have a curiosity to see if I can still have the benefits of a quad, but get a degree of pivot close to a thruster.
The board I’m using is a 6’0" x 19 1/2" x 2 9/16" MORE roundtail quad with a McKee fin set-up. Its a very refined performance quad. I usually use M3/G1000 which gives the board great maneuverability and a good amount of drive. What I’ve found is that increasing the size of the front fins to M5 or SF4 tends to make the board resist front foot turns more, and specifically check-type turns. When dropping the size of the rear fins, this doesn’t seem to change that effect, it just gives it this unusual feeling where it pivots very well off back foot turns, but is stiff off front foot and check-turns.
In the quest of how to find a pivot
closer to a thruster, I’ve found something interesting that made me think. The K-Fin fins that I’ve recently tried using came from my
thruster of very similar design to my quad, and the more I tinker with
the rear fins the closer its starting to feel like the thruster in the
area of pivot).
I thought - If it were a thruster the fin area
in the tail/rear-fin would have been somewhere around 9000-9500mm.
Changing this into a McKee quad set-up, if I put in G1000 fins the
total fin area in the tail is now 16’300mm. Quite a frikkin jump if you
ask me? Maybe the source of the resistance to pivot?
Then,
changing the rear fins to SF4 rear fins I now have a total fin area in
the tail of 14’500, a bit less but still huge compared to 9500mm.
Therefore, maybe I can afford to drop the depth and rake in the rear
fins even more so, as I’ve still got much more area to play with. The
SF4’s depth is 96mm (tiny considering the GX is 100mm), and the sweep
is only 30.7 (very little rake compared to 33.2 in the GX).
In
addition to this, the front fins can afford to be more upright and with
less rake because the big jump in fin area in the tail can accommodate
the increased pivot easily.
The resulting effect in my last surf
was great, it still had the speed and glide of the quad, but felt like
I could pivot a lot more through turns. I’ve still got more surfing to do with this combination, but at the moment its pretty encouraging.
Maybe we’re going to
need to see some new quad dedicated fins? Not just thruster fins in
different size ratios front to back, but different styles of fin
altogether?
What do you guys think?