A sailing buddy spotted this fin at a local surf spot a few days ago. this thing is for real...the "turbo tunnel" fin. Used on surf boards and some SUP boards. I remember a fin in the early 90's that used much smaller tunnels (or channels) to address cavitation. This is supposed to be about generating lift and drive, though

www.peconicpuffin.com/the_peconic_puffin/2010/07/strangest-fin-seen-in-25-yearscould-it-work.html

Certainly it looks more functional than the old "football fins" though probably a weed catcher.

seems everything old is new again, again.

from deboichet

This is from a surfboard. Made from epoxy & brown paper.

That's a work of art. The timberwork is beautiful.

Glitch said...

This is from a surfboard. Made from epoxy & brown paper.

Little Jon said...

The theory is just put out something new and different even if unproven to get sales. Maybe someone from marketing can explain better?

Make it really expensive too coz perception is everything, if it costs heaps it must be good.

NotWal said...

What's the theory behind those tunnels?
I don't get it. They just look immensely draggy.

Actually a tube has more lift than a vertical flat plane ie. a fin. Dunno the science behind it but my aeronautical father told me so when I showed him a piccy of this type of fin in the '80s. I guess if you tilt it up a couple of degrees it would tend to rise when in forward motion. Again another plausible idea regurgitated from the past. Where's the Myth Busters when you need them?

But that crescent + boomerang fin thing looks fresh and funky on that apparently faux timber board, looks sweet. Would look cool too as a night club wall light.

No real mystery there. A tube clearly has a horizontal section or 2 to create wing like lift.
A vertical fin does not.
LIft does not mean low-drag though.
Not sure that it means anything useful in relation to cavitation either.

nosinkanow said...

NotWal said...

What's the theory behind those tunnels?
I don't get it. They just look immensely draggy.

Actually a tube has more lift than a vertical flat plane ie. a fin. Dunno the science behind it but my aeronautical father told me so when I showed him a piccy of this type of fin in the '80s. I guess if you tilt it up a couple of degrees it would tend to rise when in forward motion. Again another plausible idea regurgitated from the past. Where's the Myth Busters when you need them?

But that crescent + boomerang fin thing looks fresh and funky on that apparently faux timber board, looks sweet. Would look cool too as a night club wall light.

So, when people refer to "lift" in relation to windsurfing fins, if not vertical left, then what lift is being referred to ?
A definition of lift would be useful at this point.

NotWal said...

KenHo said...

No real mystery there. A tube clearly has a horizontal section or 2 to create wing like lift.
A vertical fin does not.
LIft does not mean low-drag though.
Not sure that it means anything useful in relation to cavitation either.

Unless you're a hydrofoil you don't want vertical lift. Any surface that creates lift also creates induced drag.
Assuming its NOT trying to create vertical lift what would it do?

See, there you go. Was the nice engineering man using the same definition, or maybe thinking along different lines.
I would not have thought to use "lift" to describe lateral forces, though I can see how it does work.

scarrgo said...

the idea is that a fin creates windward lift to appose the other forces on the board such as back leg pressure

to go as fast as possible is to achieve this windward lift with the least amount of drag

and just to confuse you more... a fin is a hydrofoil. But it creates mostly lateral lift. All of those things look to me like a good way to slow yourself down and do not much else...

brad1 said...
Can you define "drive" or is this another piece of marketing hype?

I can not. I quoted a surfer who has used the thing (who conceivably might be repeating marketing hype.) And as I'm in my first year of surfing I sure as hell don't know all the jargon.

In any event, my new plan (a goofy one) is to try and put one of these on a windsurfing board, and then try sailing fin first. There seems to be a reasonable consensus amongst surfers who have used the thing that at low speeds it's good for noseriding, so just for laughs I'm wondering if there is fin first amusement to be had.

Clearly I am suffering from wind deprivation.

A surfer does get "drive", or forward thrust form a fin, in the same way you can pump a skateboard. It's a totally different principle to windsurfing though.

puffin said...

brad1 said...
Can you define "drive" or is this another piece of marketing hype?

I can not. I quoted a surfer who has used the thing (who conceivably might be repeating marketing hype.) And as I'm in my first year of surfing I sure as hell don't know all the jargon.

In any event, my new plan (a goofy one) is to try and put one of these on a windsurfing board, and then try sailing fin first. There seems to be a reasonable consensus amongst surfers who have used the thing that at low speeds it's good for noseriding, so just for laughs I'm wondering if there is fin first amusement to be had.

Clearly I am suffering from wind deprivation.

Wet Willy said...

puffin said...



Clearly I am suffering from wind deprivation.

Clearly.

Dreaming about/making/buying and/or and experimenting with bizarre, unnecessary and probably useless gear is a classic symptom!

When it's windy, people grab their favourite gear and GO!

as per Hardie's definition of Wind deficiency syndrome:

An affliction known to cause mood changes,
bouts of extreme boredom,
impulsive behaviours such as buying windsurfing
equipment which won't be used,
excessive internet use, negative thinking,
weight gain, lethargy, daydreaming,
and the occasional bout of interpersonal conflict.

puffin said...

Those are my symptoms exactly. I need treatment.

Windxtasy said...


as per Hardie's definition of Wind deficiency syndrome:

An affliction known to cause mood changes,
bouts of extreme boredom,
impulsive behaviours such as buying windsurfing
equipment which won't be used,
excessive internet use, negative thinking,
weight gain, lethargy, daydreaming,
and the occasional bout of interpersonal conflict.

There's only one cure for wind deprivation syndrome!

Wet Willy said...

There's only one cure for wind deprivation syndrome!

I can think of two:

1) Beans
2) Onions

(Clearly I'm suffering as well )

slowboat said...

nebbian said...
2) Onions

Fried... well fried... these things are fun to eat before a long flight [}:)]

not if you've got the window seat