A few questions. I usually run a single foiled keel toes in 1/4” 4 deg. cant on my Lis style fishes.
If i were to swop that keel for a double 50/50 foil fin, what are some of the differences I might notice?
I’ve read where some say that it might not be a good idea to toe in a double foil keel, why is that?
What does adding a double foil to a fin do?
Anyone?
I was experimenting with some 65/35 and 80/20 rail fins with a FCS TCredline planshape in my shortboard. The 65/35s were smooth but not crisp. definitely a delayed response and lack of projection.
The 80/20 is much better, but the original fcs TCredline is the best rail fin I’ve yet tried in this board.
I am not sure of the toe in, as Ipointed them to a spot 22.5 inches in front of my nose, but the cant angle is 6 degrees, and this is on a 6’11" speed egg/hybrid with 5 proboxes, not a Lis style fish.
I’ve tried some wavegrinder dual foil fins as rail fins4.8 snfd 5.7 inch depths, and this totally turned me against rail fins on my board that have dual foils. The 4.8 WG dual foil fin in the center box is good though. Though I would prefer a smaller version there.
The asymmetrically foiled fins feel OK in waves with more power when I am not pushing very hard against them, but in the smaller stuff when actively trying to pump and get speed they feel slow and dull.
How my impressions translates to a Lis style twin fin fish is unknown to me, i dont ride that type of board, and my board as a quad is not really to my liking, so far, in the waves I have ridden as such in.
The inside face of a double foil fin is foiled, thus increasing the toe angle of the fin from the thickest part to the trailing edge. This is why you can use less toe on double foil fins.
The board is smoother with less lift with double foil. Also go more vertical before spin out. Recommend trying double foil if board feels squirrelly off bottom.
recommend 1/16" toe over 4 1/2" length, 5 deg cant double foil
…first and best noticeable effect is discard those keel dated things and use a canard quad set up; so do you enhance the board splitting that keel area in 2 fins per side that equal the area of the keel but let you turn the right way not track.
Ok, for those bigger is better double foiled to smooth out all that area.
canard quad more release between fins, can go faster, more vertical
Keel is special feeling in right waves
double foiled fins need more toe to get the same lift, not less.
it’s simple hydrodynamics.
single foiled fins (flat on inside) have no other advantage than being easier and faster to produce, period.
asymmetric foiling, sometimes called “inside foil” is the hydrodynamically sane version of single foiled fins.
symmetric foiling reduces the board’s tendency to spin out as the outside fin will contribute more to the lift generation, however, this effect is very limited when railing heavily. This is more outspoken in windsurfing.
When used as twin keel I’d go for 70/30 asymmetric foils.
I always go 1/8th toe in on the single foils and 4 degrees cant because I get consistent results. Most are personal boards. No toe or cant on double foils. 1/4 cant seems like a lot on a long fin base keel, but admit I’ve never tried it. With all the small surf this winter I’v been using a 70/30 foil from Halcyon and enjoying that. Mike
That’s a very nice looking board Mike. I could get back into Twins with a Shape and a fin setup like that. The last one I had was a 5’8" with a full width tail no “but crack”. Double foiled fins no cant. They may have been toed in a bit. Can’t remember. The board was very similar to the “Mini Simmons” stuff you see around these days. That was back in 1970 Pacific Beach. Shaped by Ron Cunningham. He was good but didn’t stick with it. Had it shaped so I could get It in The back seat of a VW Bug when hitchhiking if need be.
Reverb is most likely right about Canards. Have heard others comment on their effectiveness.
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I agree.
Thanks McDing. I remember those twinies. My buddy and I would hitch rides to OB and back after school. He and his older brother had twinies like that from Sunset Surfboards in Encinitas I think. They both surfed really well on them in spite of what I’ve read here about how shitty they were. Big wide square or soft diamond tail. Twins way back. No toe no can’t as far as I can remember. Mike