Hydrofoil: a vessel design that lifts the hull above the water as speed increases, thereby lessening friction and increasing speed.
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Hydrofoil: a vessel design that lifts the hull above the water as speed increases, thereby lessening friction and increasing speed.
Encylopedia Brittanica:
Main Entry: hy·dro·foil
Pronunciation: 'hI-dr&-"foil
Function: noun
1 : a body similar to an airfoil but designed for action in or on water
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Your olo with coffee can is to “Hydrofoil Surfcraft” as is to “Airfoil Aircraft,” SPAM.
I have never built an OLO with a tunnel fin.
However, you might try reading this post, which you appear to have missed in favour of a cheap shot at the vort-X fin:
"One of our previous successful hydrofoil designs from the mid 90’s were two inline singlefins with flat bulb tipped foils attached to each fin. . . foils 12 inches across and two inches fore and aft, half an inch thick. The front inline single was 25% up the board from the tail, the back one right on the tail. . . . the front single just tall enough to mount the wing 3 inches or so from the bottom… . the back fin ten inches deep with the wing 5 inches from the bottom. … . the front wing a degree or so higher in AOA than the back one. … . and by the way,
they flew !!!
cheers,
Roy
PS would you like a drawing of the setup?
PPS The setup mentioned above was attached to lightweight chambered balsa longboards in the 9 to ten foot range, and also to balsa shortboards. . . so shut the F up about ‘respecting’ this thread because I was ‘flying’ boards with hydrofoils back in the nineties. … so I know what I’m on about. . … I hand built many hydrofoil setups with marine ply, kevlar, and graphite/epoxy. . . . . all hand foiled and finished while working under canvas. . . . they worked and we used to call them ‘crucifix fins’
!!!
Come on girls, this is an interesting thread…
I’ve always imagined a twin hull would assist in providing more lift in conjunction with foils, or at least a stepped hull…
Anyone tried these methods???
We’ve had a request to keep this thread going…
Ready…
Set…
thanks !
Hey yeah, thank you. Mea culpa for the degeneration back there–deleted inflammatory materials–apologies all around, and Roy specifically.
G bless Swaylocks, and our hon. mods
J
take a look at these:
international moths, they don’t even float unless they are moving, they seem to have the foil design down pretty well.
Amazing? How do these guys keep their balance??? I found a nice hydrofoil windsurfing clip:
http://www.youtube.com/watch?v=1oyWMusaDTI
can’t wait to stick one to my paipo-board 
Thanks to the infinately wise MODS .
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Amazing? How do these guys keep their balance??? I found a nice hydrofoil windsurfing clip:
http://www.youtube.com/watch?v=1oyWMusaDTI
can’t wait to stick one to my paipo-board
Hi Brett!
Thanks!
i had a look at Terry’s amazing kelp-cutter before and tried to read all the stuuf he wrote about it but lost it pretty soon ( i’m not that good at math’i’m afraid). But very inspiring for sure. Maybe i shoulkd stop thinking about it just make one and see how it goes 
In Dale’s post at the beginning there are a few pictures of the plywood hydrofoil paipo, and it looks like there no upward angle or a aeroplane like foil on the wing. Anybody knows more about this?
I also have looked at hydrofoils on boards, scarey! I do know how the hydrofoil moths work. Both the centreboard and rudder have foils and both have trim tabs. The centreboard trim tab is controlled by a carbon fibre wand sticking into the water at the bow. As the boat lifts there is less wand in the water and less drag on it. A cunning series of linkages go down to the foil tab which is thus adjusted to reduce excessive lift and the whole lot just taking off.
The rudder has a similar tab but it is controlled by the helmsman. There is a twistgrip on the tiller (like a motorcycle accelerator) and as the bow lifts the rudder foil is adjusted to keep the back lifting at the same rate. Takes some getting used to but the good guys can tack and jibe without comming down off the foils… I am in the process of putting a retractable foil on an old long board and hope to try one front and back…yuuck!
Has anyone seen or heard of a paddle in standup hydrofoil as of yet? It seems that the drag of the foils in displacement mode would be tough to overcome and catch a wave, even if you had some symmetric foil with flaps that you only deflected at speed.
The following is a link to a prior thread, search on ‘Product - Pole’, no quotes, but include the hyphen.
Please note: As indicated in last diagram in thread referenced above, handlebar streamers and bell are extra.
Kevin
Thats pretty great, I think you would need the streamers, it would be faster
As mentioned previously on this thread I have done exactly that (standup paddle in hydrofoil board) back in the 90’s, and if I read Spuuuts posts correctly he is doing it too.
Regarding drag in paddling mode, just keep the lift angle small and the foil section thick so that the foil can handle the angle of attack during paddling ( well that’s how I did it anyway, and paddle speed was fine). . … even a small angle of lift will get you up there.
I dont really agree with his “72 square inch” total foil size.
Regards, Brett.
Hi Spuuut,
If your setups aren’t secret then it would be cool to see some pictures.
Not sure what you mean by ‘rubbery’ maths, I can’t recall posting any maths on the subject at all.
The 72 square inches of foil area is low for sure, the boards did lift though (high aspect ratio wings), they would spend some time contacting the water at lower speeds and then lift out completely when going fast enough. . . . because the foils were close to the bottom and at a low lift angle the transition between foiling and semi foiling was smooth (kind of a transitional hydrofoil?) . … . I imagine that the transition would be more marked i.e slower when not completely lifted out of the water with a greater lift angle on the foil.
We had the front foil parallel to the bottom ( a slave foil) and the aft foil at nearly the same AOA as the front foil (which because of the bottom rocker meant that the aft foil had a positive angle of lift at the tail. . .
It felt amazing not contacting the water, the feeling of the foils was like riding a school of big fish, I could really feel all those underwater forces at work beneath my feet, have you noticed that?
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Here a pic of the first one I made. Brett.
Just figured to put this pic originally posted by Mr Mellor on the Hoop Dreams thread in its rightful place.