This may be of interest to one kneelo out there in big land.
In the small waves here recently I've been finding this assymetrical setup works.
Its for the surfer who surfs with one knee forward and has one leg weaker than the other. In my case the left.
Idea is to move the fulcrum point forward to get it under the proper part of my leg. I also want to make it looser to alleviate the relative weakness in my left leg.
The front fin under my weak side (MRTFX circa 2006) is larger than the right, but has less rake and is set further forward. The lesser rake keeps the fulcrum point further forward for most of the turn. The well tuned flex in the MR helps counteract the size.
The small fin behind it acts as a stabilser and helps stop theboard sliding while adding little to the actual drive. Consquently, compared to a normal quad, when going left, you need to lock in the rail even more in front of the fin during the bottom turn - as in a traditional twinnie.
Interestingly this fin is borrowed from my circa 1983 (?) Dale ponsford shaped (no 148), Peter Ware "original 4 fin."
The dominance of the front fin in turns keeps it loose but drivey off the top.
It also helps with rentries on right handers (where they are the outside fin) because you pivot off the front fin with no interference.
Pic 1: showing general setup
The fins under my right hand leg are a more traditional quad fin cluster.
The tabs on the front fin are set so that the fin sits further back in the plugs (this fin is molded home made job).
It has more rake which keeps the pivot point further back during the latter part of the turn.
This setup with the slightly larger back fin (and tighter cluster) gives more drive than the other set of fins.
Unfortunately the back fin is still too small to give quad boost though as you can't really push on it in the last third of the turn.
Bear in mind it's for very small waves and you don't want something too drivey at the expense of looseness.
Compromise is a way of life.
pic 2: side view of the fins to give an idea of the relative sizes. Bear in mind that th fin box fins sit further into the board than the fcs fins. The last fin on the right, hand molded, when combined with the other molded fin, gives quad boost about 70 percent of the time on this side of the board.
another few pics:
pic 3: the difference in rake:
pic 4: the difference in aft/nose displacemnt of the fins
all in all you could call this a stabilized tri fin
let me know if this is of interest
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next in line is a quad with a central fin box.
time to try three smaller fins on side (two quads and the centre)
and a larger fin on the other - as in a traditional tri
no growth.