FCS fin manufacturing - Chinese factory video

[Marc]

You could spend your whole life messing with fins. And if you do, post the results.
The twingle setup allows for a smaller set of fins. How much is up to experimentation. The twingle setup is heavy with traditional boxes/fins, so smaller fin size is good.
You can build fins and postulate up to a point. The best test will be in the water.

[Railwaysurfer]

Ooh that’s got the wheels turning!!! You could get a base machined out of light weight aluminium and use a machine screw to fix different fin templates over the base. You could do the same with solid fibreglass I guess?!
What would stop you glassing a solid base onto a board and having a “cover” fin slip over the base? You’d have the advantage of glassed on security with the interchangeable aspect of boxes?

[stoneburner]

The old Morey-Doyle closed-cell foam boards had an embedded FG tab that rose out of the board. The fin slipped over the tab and was held in place with 2, 2-piece screws.

[jspr]

Hey Stoneburner , thanks for helping out!
Took some time to read through.
I’m not sure if I understand the below regarding the distance between the fins:

“this shows indeed that fins close to each other should have roughly the same size as the single fin. While a twin fin on the rails can reduce the fin size to almost half the size.”
Below the quote from the OG post…

@hans

this shows indeed that fins close to each other should have roughly the same size as the single fin. While a twin fin on the rails can reduce the fin size to almost half the size.

However, the further the fins apart, the less the positive effect of the inside fin (~ upper wing) on the stall angle of the outside fin.

The statement that you can use more upright fins also makes sense. Sweep in single fins soften the stall by twisting and therefore reducing the AOA at the tip. And since the Thraikill fin setup softens the stall angle by the fin interaction, less sweep is needed. The more upright shape may result in a looser feeling.

This fin setup makes perfect sense to me. However I’d go for double foiled fins since the inside fin (~ top wing) is responsible for more than half the lift generated.

[Railwaysurfer]

Oh interesting, just goes to show that just about everything has been trialed by someone, somewhere at some point!!! I wonder why it never took off, seems like a good system? Manufacturing ease maybe a reason the current system took precedent?
I need to read the Twingle thread, still going on the Thick vs Thin!!!
I’ve trialed the Duo set up and really like it, just a case of bringing them in a bit closer!

[stoneburner]

@jspr

I’m not sure if I understand the below regarding the distance between the fins:

Wish I could answer. But I’m not an engineer in fluid mechanics.
However, Hans is an engineer.
And I have respect for Hans’ knowledge and insights.

[jspr]

I feel the same. I asked him , to understand his answer more homework on my side is required;)
My problem is that Im not sure if I understand the vocabulary in the first place.

[stoneburner]

I’m a retired scientist. While I have some decent understanding of the most basic concepts, for me, fluid mechanics gets very abstract fast.
Here is some more of Hans’ input about the Thrailkill Twingle.

Thrailkill's Twingle Flow Visualizations

I’m late to the party, but please allow me to give my input. Below I’ll talk about top and bottom fin as if those are biplane wings, it just simplifies the explanation and corresponds to how the image is laid out. [[{“fid”:“116958”,“view_mode”:“default”,“fields”:{“format”:“default”,“alignment”:“”,“field_file_image_alt_text[und][0][value]”:false,“field_file_image_title_text[und][0][value]”:false},“type”:“media”,“field_deltas”:{“2”:{“format”:“default”,“alignment”:“”,“field_file_image_alt_text[un…

[Nigelnz]

I was wondering after the fact of developing a fin that really works and is like a night and day change how would you begin to get it out there or into one of the lineups for these fin companies. who would know of a contact for this, its a twin fin design. Ive been running it on my hollow wood surfboard 7/0 performance shape. Its so good I would like to have an actual fin maker look at making some. or at least try it. Ive tested it against all sorts, power twins, keels, it has something over them all

[lawless]

Nigelnz, I’ve heard NVS fins will do custom small-batch runs.

It’d be worth reaching out them, if they can’t/won’t do it they can likely connect you with the right company who can.

NVS Surf Fins, Leashes & More

[stoneburner]

You might want an NDA agreement and non-disclosure contract before showing your design to a manufacturer.
The business world can be ruthless/shameless.

[Nigelnz]

Hi again. Thanks guys, i agree. I really want to show you guys a pic but it will be gone in a second. its a real game changer, honestly on every board it somehow makes drawn out turns and sharp turns in the pocket feel buttery smooth and controllable, it definetly something no one has come up with before and unique, and works. I just wont surf another fin now, and these are twins of all things

[stoneburner]

I should have said “Non-Disclosure-Agreement” and “No-Compete Contract.”
Good luck with your fin development NigelNZ.

[jspr]

Would be cool if you keep us posted on the developments.
I was thinking of NVS too, if your fin can be cut from a standard panel. They offer a lot specialty and shaper cooperation fins.
If your fin is somehow different in the 3 dimension and would require a very thick panel to cut it out you should probably look for somebody who is also moulding fins. Hanalei fins/Robin Mair would be a company that comes to my mind …

[arlosilva]

Semi related to this topic.

Is it a bad idea to make a silicon mould for fins and then make the fin on the mould?

Will pe resin eat trough the silicon?
Will it work with epoxy?

Cheers and good waves.

[Nigelnz]

Will keep you informed. NVS have responded positively. I think I will dial in my programs and files and get together half a dozen clean sets in alloy as the fin developed in alloy after iterations may be dependant on alloy in terms of its flex and design. or i have come up with a twin fin design that works in both. Will get clean ones and try getting some made with arrangements by NVS next year perhaps. for now I only use them since they are so much better so there will be alot of time for durability and anything else that may happen in the mean time. Will keep you all posted. One day you might actually see them, sorry about that in the mean time!!