With nothing other than a "first random" thought flying through my head ....
Wouldn't it make it hard to gybe? Wouldn't the horizontal plane want to keep the board flat?

I'd mount them pretty much flat, maybe only a very flat angle (1-2 degrees) if you must.. then you can add/alter the angle of attack by leaning on the back and lifting the nose. That way you don't suffer too much nasty drag, and also don't end up having to ride nose down once you actually get planing.

Sounds like a fun experiment! If you're clever you might manage to make it so you can tweak the angle of attack to see what works best..

I have a few ideas like this myself, but just in case they actually turn out to work, I'd better not share too much!

I am no expert but i know a little about moth hyrofoils (sailing boat) i don't think it will provide additional lift unless the profile of the wing is cambered one way ,www.fastacraft.com/moulded_foils.html

Nebbie,
I won't claim that I know what is going to happen, I also tend to think that anyone else who believes they can predict the outcome of your experiment with any degree of accuracy is just guessing.

There are just too many variables involved, the biggest variable is your own ability to attach two cut down fins in perfect symmetry and identical angle, with enough strength to withstand the potential forces involved. (...but it sounds like just the crazy experiment I would love to try myself.)

However, I am pretty sure that owain is on the money about needing an asymmetrical foil to generate lift, that is going to be the biggest let down in your plan. I expect that all you are going to ultimately achieve is increased drag and reduce your chances of ever planning again.

It's worth noting that these days a prerequisite piece of equipment on practically every outboard motor are hydrofoil planes. They are fitted on every outboard from 15 to 250hp, claiming to allow earlier planning, lower planing speed, increase fuel economy and increased stability.

I wish you every success with your experiment but suspect that "hydrofin" technology involves a little more engineering and manufacturing than is available in your garage.

Good luck, and remember to post photos.

ive sailed a foiling moth and they are had work to keep up and to balance but the other thing they have that u wont is adjustable lift (flaps) so they can control height i thing it would be almost imposible to do that on a board so it will take alot of time to get it right

but atm i am using a rudder foil on my 14ft skiff to stop it nose diving on the spiny runs and works a treat , i would like to make it fully foiling but im scared at the idea of being 1m up both out on the trapeze with the kite up then cartwheeling it

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Originally posted by 555

I'd mount them pretty much flat, maybe only a very flat angle (1-2 degrees) if you must.. then you can add/alter the angle of attack by leaning on the back and lifting the nose. That way you don't suffer too much nasty drag, and also don't end up having to ride nose down once you actually get planing.

I have a few ideas like this myself, but just in case they actually turn out to work, I'd better not share too much!

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Nebs & 555 - also been thinkin' this one thru, but in terms of a speed foil fin, as the wetted area & fin &/or cavitation appear to be limiting factors for +40 knts zone

Can't tell you too much though
Perhaps some of the speed demons may have some ideas (bet they don't share the good ones...just the theory)

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Originally posted by hobie14t

Hey Nebb, sounds like you need a Hydroblade!
www.seabreeze.com.au/gallery/gallery.asp?imageid=2171

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Hey Hobie,

Do you have trouble with it catching chop and suddenly slowing you down?

The thing is, the winged keel is the sort of fin that I only want to use in winds that I normally couldn't plane in. Say 10-12 knots. I'm hoping that it might give just enough lift to pop over the bow wave.

The other alternative for early planing sounds too much like excercise

www.seabreeze.com.au/gallery/gallery.asp?imageid=3872

KITE BOY!?! Back from the sin bin

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Originally posted by nebbian

quote:

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Originally posted by hobie14t

Hey Nebb, sounds like you need a Hydroblade!
www.seabreeze.com.au/gallery/gallery.asp?imageid=2171

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Hey Hobie,

Do you have trouble with it catching chop and suddenly slowing you down?

The thing is, the winged keel is the sort of fin that I only want to use in winds that I normally couldn't plane in. Say 10-12 knots. I'm hoping that it might give just enough lift to pop over the bow wave.

The other alternative for early planing sounds too much like excercise

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Hey Nebbian,

Yep, your spot on, it does catch in chop and slow the board down, rather rapidly if you know what I mean [}:)] One such time was when I was in the high 20knt range. not fun.

Greeny, you know I'd never give you a thumbs down

In your experience, has any form of winged keel contributed to early planing? I'm sure the experiment has been tried...

Well.. seeing as it sounds like everything has already been done, we may as well all stay home all day, turn off our brains, drink beer and watch infomercials on TV.

By the way - the world is flat, man will never fly, and all medicine is [}:)] witchcraft..

Imagine the uproar if someone started redesigning boards specifically to use hydrofoils!

I guess I'll head back to my workshop and undo the modifications I'm doing to the bottom of my AHD, seems like there's no point anyway.

Bollocks to all you negative people. Get in there and have a go Nebs - you might find some inspiration in the midst of the dust and glue fumes and come up with that one idea that nobody else has had, and make yourself your first million.

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experiment. ok guys going by the numbers of thumbs down i got from that post( at least 7)
who is going to be man enough to explain why you object to what i wrote. seemed innocent enough seeing how i have actually used all those fins over the decades......hmmmmm

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I'll have a go greeny.. When I was much younger I experimented with riding a bike. It was crap. I fell off a lot, skinned elbows, knees and it generally didn't work at all well.

In my case, the bigger kids in the neighbourhood seemed to be able to do it, so I knew it must be possible. I persisted and now I can ride a bike quite well.

Imagine back to the first person to invent the bicycle. They didn't know if it was actually possible, and the prototype bike looked (and handled) nothing like what we know today. How many variations of bike have been designed between that first one, and what we're riding today? What are the chances that that first person was the laughing stock of his peers as he careened around the place barely in control with his coat tails flapping behind him?

I reckon we should encourage Nebbian to be that out of control lunatic with his coat tails flapping. If it does work, well, we might all be riding around on neb-fins in a couple of years wondering why we didn't think of it ourselves.

And if it doesn't work like he hopes, it could still make for some entertainment for the local villagers.

Villagers like being entertained!

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Originally posted by greenleader
all done to the max in the 80's and 90's. like really really done!!!

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Thomas Edison made the first public demonstration of his incandescent light bulb on December 31, 1879.

IT WAS ON HIS 109TH ATTEMPT/EXPERIMENT THAT HE SUCCEEDED

Go for it Nebs, & don't let the new job interfere

lads, not being one to ever put down human endeavour or experimentation, but being a guy who types with one finger and doesn't elaborate too much cause one finger gets tired.

i highly encourage playin around with all forms of windsurfin stuff as i have done for quite a few enjoyable years! i didn't think that dickin around with a couple of weed fins would achieve much but now remember that i used to always do that sort of stuff,(most memorable fin we made was called the mermaid raper shaped like a dick)wish i had a photo(no i'm not gay)

go nebs and other equipment scientists, i have been blind to remembering those days.