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?
Rules we dont need no stinking Rules , get yourself a longboard with side bites , remove the center fin replace the side bites with a pair of large twin fins or , I used to use FCS curved fins works great .
How does a twin fin longboard ride? I had a quad longboard for a brief time, and liked the way it rode, but didn’t get to ride it enough to pinpoint what was different. Looking to try a quad longboard again soon.
I always picture the ideal candidate for a twinny as short, with a wide tail. Like the old school fishes used to be, or a mini simmons.
My friends riding their longboards as twins use the side boxes with large twins and no center fins. You could probably add a set of plugs for the rear FCS plugs you already have, but then you’d have to cut off those large fins if they are glassed on. The twins I’m riding now are mostly short boards (under 6’), but I like my fins a bit further up. I use very little toe and cant and prefer big keel fins. The wide base seems to add more drive.
The board below is 7-10 and I’ve been having fun riding it as a pig twin in small waves (shoulder high or less). No toe no cant and the fins are almost 2 inches in from the rail. I’m using standard 7" single fins.
Other wise the stuff that Simon Jones is doing with twins might be worth researching.
How does a longboard with twin fins ride , well to be obvious it rides like a longboard with twin fins , it changes the whole feel of the board , gone is the stability of the large center fin , depending on the fins you use it can be very loose , thats why imo the curved fins work so well , I am surprised more folks dont try it as its so easy to do , if its too loose and you cant get the curved fins just add a very small trailer fin to the center box . its like getting a new board that looks like the old board .
Never having tried one that felt right makes me curious how and why some guys are able to make a twinny work.
It seems to make sense how the wide tailed fish can be workable because they seem like 2 pintail SFs placed side by side and the tail that’s deepest in the water generates some drive that way. But then when shapers pull the tail in and add curve to the rail line and the corners of the tail get closer together and the fins toed in it seems like it would change the dynamics significantly.
Is there any such thing as a twin fin that generates drive or is it all just about pivoting on the tail and getting drive by sinking the rail?
I only surf twin shortboards because it’s go well with my front foot style in south France beachbreaks. i move to twin from quad by adding plugs in middle of my McKee’s inspired quad placement with 0 toe and cant for rears. I do quad lb like this so if i have to make a twin one i would do the same, ended with 1/16 toe 2 cant.
I´m a front footed surfer. And with the last couple boards I found my love for pintail twin fin boards.
Actually I didn´t think it would work out for me but I was curious.
I made a 6ft2 and a 6ft4 that worked good/normal (good, but not magic boards).
My last pintail twin is this 6ft10 x 20.5.
I rode it only twice, but a lot of things instantly “clicked” with this board and my surfing. Feels like this is a magic board for me.
I ride my boards from the middle (I don´t step on the tail so much) and this one has really good hold and impressive projection and speed out of bottom turns.
The longer board seems to fit my surfing style. It was intended as a kind of stepup to the 6.4 pintail twin (similar shape and 4channel bottom as well). But I think it will be kind of a daily driver for me. The first two sessions were more like everyday waves and it worked so good. I rode it with a self foiled fin set that is similar to the fcs power twin.
So what´s the rule for making twin fins work ? I absolutely don´t know. But I would like to.
I find it interesting, that you are bringing up those Twins in combination with those bigger boards (fun gun style).
Because that´s exactly whats going round in my mind recently.
I have built some “fun guns” in the 7ft -8ft ballpark and I really enjoy those boards. Kept it simple with the fin setup on those boards (2+1 or quads) till now.
But considering how much fun I have on my new 6.10 stepup twin, I really wondered if a 7.4-7.8 fungun with twins would work for me.
I only had a few bigger takeoffs on the 6.10 till now. But it always felt composed, predictable and overall very good.
In a way that I really want to try to upscale this board into the size of my funguns.
I´m hesitating though. I mean, Torren Martyn makes it look so easy and smooth when he surfs that 7ft9 Simon Jones “Massive”. But usually that´s not the case for an average joe like me and I shouldn´t be tricked by those videos. There is a reason why almost everybody else is riding those funguns as a single/widowmaker/quad and not as a twin.
On the other hand, everything feels great on the 6.10 for me. Why not built a twin version of my fungun and see how that compares to it´s Widowmaker/Quad sibling.
So, I´m really interested how it works out for you. Let us know how it turns out.
Don’t know if this will help at all, but Torren Martyn seems to be all twin fins all the time. Quiver review, cued up to his “longer” one(s). Shows how they work in good waves under skilled pilot
I anticipated something like this, so I put channels on my prototype, before I ever bothered to ask. But if I’d seen this video I would have extended the channels out the tail.
I lammed the bottom already so it’s too late to change it.
Channels have a directional stabilizing effect and that was what was lacking on my v bottom board when I tried it as a twin.
I think the wider the tail , the better a twinfin will work…" the principal of twin-fins is that one fin slows , and the other one revovles around it"…Geoff McCoy.
I don’t know if anyone has noticed, but the rails on this shape are hooked downward slightly, starting a couple feet ahead of the fin. Then there’s a wing that is placed behind the trailing edge.
This creates a channel on the outside of the fin.
I have a friend who had a Gordon&Smith twin swallowtail that was like that. It was his favorite board.
Shapers and glassers generally try to avoid designs like that because it really adds a lot to the production time.
It’s good to see that there are guys in the surfing world who have developed the skill to create complex bottoms and keep alive some of the designs that guys used to produce for the public, years ago.
Owning/surfing a board with a complex bottom is a statement
Today I’ll do things like that for a friend or for myself… For a friend if he’ll acknowledge that a complex bottom isn’t easy, and I’m doing something that most other shapers wouldn’t do.
Just to complicate an even more complicated topic, imo there are teo different answers to yr question abt widths/twins: (1) in general wide tails/boards are more likely to end up being ridden as twin or quad if a wide array of combos and layouts are tested, (2) a narrower tail such as on older short boards (I’m thinking of a G&S step I recently stubbed, keeping the ol skool tail) and steps is more likely to produce hold via the tail design, and thus be twin friendly as far as the board itself doing some of the work of a center fin. Seemed like this suggestion belongs in this thread…
