I have tried twin fins, but only on boards that were originally designed as tri fin boards, and I tried converting them to twinzers, which I was happy with and I felt that the modification could be considered successful.
See posted picture.
As a twinzer the drive, bottom turn speed and top turn speed are better than a tri fin. suppose there could be some improvement should I decide to go to the trouble of re-locating the fins and experimenting, but I probably won't, because of the labor intensive factor.
So anyhow, the small leading fins on the twinzer clusters are removable and with that I have is a genuine twin fin... And it is very loose and lacking drive, to the extent where it's not functional, as could probably be predicted.
Here's what I'm wondering : What design and fin placement differences does it require to make a twin fin that is actually functional?
I have seen but never tried a twinnie longboard and it looked like the fins were about 6" tall and they were toed in a bit and they were about 2" in from the rail and maybe 9"-10" from the tail - But that was just eyeballing it.
Also what I see are twinnie fish that have keel fins with little or no toe-in.
The fin system on my own board is 5-3/8" fins placed 9-1/2" from the tail canted 5 deg and toed in 5/16" - That is a 13-1/2" tail on that board - It's a 7'8"
Does anyone have any experience with designing a successful twinnie longboard?
Thanks for any info - looking forward to replies!