The way of the future...

General Discussion
21

Ive finished the foils and struts and Ive had a few surfs on them.

The whole kit is obviously heavier than a board alone but it floats just the same because I picked a thicker board to compensate. With all the extra area it does pick up quicker and shoots off down the line, at speed it does little airs or ollies if you lean back but if you ride conservatively it lifts up and smoothly does what it does. Even though its on a bodyboard it turns and feels like a longboard. It doesnt like to slow down/ stall for a tube but it likes to run ahead when the wave walls up further down the line. Its like a salivating young dog on a lead.

Using shorter struts has made it really stable, it does skip on the water surface at speed but it lifts back up straight away. The ‘pitch’ of the board is not as troublesome as it looks to be for Laird, he got lots of height from the long vertical strut but the foil setup he chose was designed for instability and vertical tricks behind a tow boat. The shorter struts put you in better control of board pitch.

I havent tried it on anything overhead or really hollow, honestly, its a bit fucking scary at full speed. A french guy had one wave and slid off and said “fuck its fast !” A few young guys saw me take a few waves at Burleigh and they just stared. Im keen to make a better foil, this one has a total foil area of ~ 320 square inches but I think if I can combine the same area into one foil then I will get full control for much sharper turns,( I can feel that there is a bit of fighting for control between the 2 foils when the wave gets steep.) Maybe put some wingtips and use flat ply/carbon layered foils. The current foils are only slightly foiled and they work fine.

No action pics yet but if I can get a mate to ride it I will certainly post the pics.



22

Hey Brett -

Brilliant! I love it.

Here’s an idea I’ve been brainstorming but haven’t quite worked out the details…

In a similar fashion of using a fore and aft foil but instead of ‘fixed’, why not set the forward foil on a pivot with a couple struts or cables through the board that could be controlled with thumb loops or levers on the deckside? Maybe include a spring loaded return the foil to a neutral position? Maybe a thick/blunt forward edge for a wider angle of attack range?

Picture something the trailing wing flaps on an airplane… the angle of attack on the forward foil could be increased to lift and once the hull is out of the water, maybe feather or flatten them out for more speed?

I agree with Pete (Itz) on the forward and rear angle of attack specs. It makes perfect sense that as the forward foil lifts, the rear will follow. With an original negative angle of attack at paddling speed, it would become more neutral in climbing mode. That is all worth considering in the overall design for sure.

Keep it up!

23

John, thanks for your reply. I too believed that the 2 different angles would be the ‘way to go’ so I did try (many times) the setup where the front foil was at a more +ve angle than the rear one and it made paddling a lot harder, even at 3 or 4 degrees it was something that you could instantly feel was slowing the paddling. The increase in foil angle also caught the rip or flow of water along the beach when waiting for a wave and it dragged me further and faster out to sea or along the beach.

I then put both foils at 0 degrees just as a ‘control’ experiment and that worked best, it had the minimum paddling drag, didnt get caught in the rip and didnt make any appreciable difference to the ride. I would say that having both foils at the same 0 angle made the board faster because they werent fighting to set their individual balance. There is never any issue with geting enough lift or pearling. I dunno why , it just doesnt happen.

I know having both foils at 0 degrees shouldnt work out in theory but if you try it you will see that it works in practice.

It also makes riding the board an intuitive experience because the foils are at the same angle as the board so I know exactly how the foils are facing the water by the angle of the board.

I remember Terry Hendricks writing that the water on a wave ‘comes up the face at an angle of 17 degrees’( or similar), so it hits the foils from the underside ensuring lift. In fact the foils start to stall when the board is horizontal ( on a sloping face) so it has to be kept tilted slightly nose down to accelerate. Pointing the nose further down ( negative angle to the water surface)doesnt slow it and at its worst it lowers to touch the surface and lift back up again without any fuss.

I went through a lot of anguish drawing, searching and planning out complex flow possibilities and studying glider wing angles but in the end a foiled board with short struts doesnt have a lot of vertical room to move like an aircraft and it is now the easiest design factor to replicate.

24

Hi Brett -

I have absolutely zero experience with hydrofoils so I definitely take your word on it on the neutral angle of attack. I agree that what ‘seems’ right in theory doesn’t necessarily compare with actual practice.

25

John, Im now attracted to finding a versatile single foil outline instead of using 2 rectangular ones. With a wide straight leading edge the board reacts in a ‘digital’ way, it instantly responds to input. I think if the foil shape had swept back wings it would have smoother response.

Theres also working out what sort of standup vehicle/ board the foils could be attached to.

And how to attach them.

The kids who saw me riding it yesterday came over and asked where I got it and how it worked. They were more stoked than I was.

I think it could be made as a standup board, not with boots or straps but as an alternative way of riding, just needs some time and a few prototypes.

26

IS THIS TRUE???

27

The pic came from Riptide magazine in Australia, no 152, August 2006.

Heres a few other pix from the article.

Its true.

28

I stand corrected. Guess your the guy running with the ball. Just wondering why you have two planes, off set at different depths, instead of just one?

If you were to do this one a stand up board do you think it would go in the tail or more in the middle?

29

I should thank you for starting this thread because I wouldnt have re-visited the hydrofoils I did back in 05/06. Thanks.

The foils are at 2 depths because I thought that if the front one breaks the surface and loses lift, then the rear one , which is lower, will still function.

And also because I felt that the front foil would cause turbulence that would reduce the efficiency of the following foil if they were on the same level. Maybe yes, maybe no, but by seperating them it would reduce the chances of it happening.

I dont think it matters where the foil goes, the rider has to straddle the setup to control the pitch, so if you like standing further forward youd put it where you wanted your centre of gravity to be.

Laird had his back foot almost above the foil so he needed a strap on his front foot to control lift of the nose.


30

…hello,

what happend to use this with a shortboard in a normal clean hollow wave?

Im talking about the take off

is it possible to take off the wave paddling?

I think is not possible and over the falls will occur due to lack of velocity and too much “first steps harshness”

thanks

31

Hi Reverb, on my first wave with hydrofoils a few years ago I chose a perfect head high tubing left on a beautiful sunny day, perfect size wave for my skills, confident in my equipment and ready to experience something new ( for me)

And yet I was shitting myself that something horrible was about to happen.

But it didnt.

I had all the scientific knowledge that it would work but I still believed at the moment of takeoff that it wouldnt. Instead,the board just smoothly lifted up and accelerated down the line with seamless transition.

I dont know exactly why it does, but it does.

Terry Hendricks , who I think everyone here respects enormously for his knowledge of wave science has for many years ridden hydrofoiled boards and I think he would be better prepared to explain why it is so, but foils are easy to ride and the take off is smooth. Maybe its because of the extra planing area or because that the foils are seated ‘within’ the energy of the wave rather than sitting on it like a standard surfboard. Dunno…

Years ago, some bloke from New Zealand claimed that he too had made and ridden hydrofoiled surfboards back in the 80’s (?). He was asked whether the takeoff was a problem and he simply said “no”.

Only someone who has ridden a foiled board would know that its a seamless transition from paddling to riding / planing and thats why I believe that Roy Stewart was the first person to ride a standup foiled board. imho.

Apart from that historical aside, if you get the chance to see or try a foiled board, you’ll see how easy it is , and thats the amazing thing about foils, they look odd but they work.

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32

…Surffoils thanks,

the dunno but it works" …reminds me that bonzer thread…

but Im still have doubts about hollow average waves riding

is it possible to have a modern “radical” surfing?

or is a complete new ride in itself?

all that air between the rider and the wave is prone to new complications, like keep the balance (the surfer); the boards work with “strength impulses” from the legs, etc but in a “closer” relationship between board, surfer and wave and in those foils cases, seems that the “move” is other

is it right or not?

thanks again

33

Brett

You are my hero

Tom

34

Reverb, I say " I dunno" because I dont want to come up with theories that I will have to abandon/recant/defend later or make the feedback fit neatly into a 1/2 baked theory. I have no idea whats happening under there but I happily give you my feedback and hopefully someone else can figure out the whys and hows.

Heres a bit of feedback,

This is the result of doing cutbacks on shoulder high waves, they were gutless, lumpy waves but the foils lifted quickly. Maybe the struts are too long at 12 inches or maybe the area of the foils is too big at 320 square inches. Its all working but somethings not strong enough.

I think the foils are too big because even on waist high waves they lift straight away and skip on the surface and thats when it slows down.

It hard keeping the foils UNDER the surface.

The foils are 20 inches wide and when paddling Ive cut my fingers a few times on the leading edge of the front foil so Im going to move the foils back and take an inch off either side before I take a finger off.

When the foils are at 90 degrees to the water flow they are really responsive both in lift and control… e.g. When paddling onto a wave they are strong, but when I turn and point the board along the wave they lose power and I think it might be because when I turn I am changing the angle that the foils face the flow of water. Im going to try a swept wing type of foil next, ditch the 2 foil config and just go with one Delta shape like this. 18 in X 21 in.

And in this sort of position.

Ive found moving the foil back makes it balance and turn from the back and it feels safer. This foil is 154 square inches, less than 1/2 what Im currently using but bigger foil area is good for staying way out on the face but a smaller foil should let me sit back were everyone else is surfing.

Theres a similar feel to riding a standard bodyboard but more smooth and stable. I think the vertical struts might act like a high aspect vertical fin, like the Wavegrinder or a Spitfire fin ?

Each wave I took had more people looking so it must look really different but controlling it is much the same as standard surfing except I can glide over chop and foamy shutdowns.

Its must look freaky to see a fat old man flying totally clear of the water ! Not even my flippers are in the water. From a distance you might not even see the struts.

Reverb, as to whether its classed as “modern radical” or “a complete new ride”, thats not for me to label. Is Lairds foil surfing radical or new ?

Tom, you have very low standards, but I’ll take your compliment all the same. Thank you.

35

…Hello Surffoils,

very good info that you re sharing

thanks

I see that you ride a bodyboard so you re riding prone style

but Im still skeptic in riding those foils stand up in a shortboard in average size fast hollow beachbreaks trying to perform a modern surfing

for me L Hamilton foil surfing is not too much radical in moves

is very radical in itself; the fact that ride those little foils in those big waves are pretty radical

so is like tow in, etc

is another type of wave riding

but not (yet) the new way of surfing

36

Technically I know these foils at 320 sq in can lift my fat arse of 90 kgs at low speeds so it should be possible to put smaller ones onto boards for lighter, younger, fitter, faster surfers to ride. Riding closer to the curl and bigger waves seems to bring a lot more energy and lift to the setup so it might be possible to eventually use a foil about the size of a dinner plate or less for experienced surfers on average waves.

What levels of performance are then likely, I cant guess.

Maybe it might need some alteration of a kind of strap,boot, moulded foot-well for standup surfing but its no more difficult to ride than any other board.

It is a head-trip to paddle into a wave and then see the water drop away underneath you !

When this thread dies Id expect any interest to die as well, so I dont think it’ll go anywhere commercially but for the moment its a bit of fun to play around and see if I can come up with something to hang on my wall or stuff into the garage with all the other mouldy boards, solidified resin and damaged fins.

Im still hoping to get a few pics just to show it in action.

37

For example:

a bidirectional kite board is the fastest “hull” on water (wind, of course…) and at the same time they are “foils”…

38

After the last set of vertical struts buckled I made thicker ones but the same length.

I drastically reduced the area of the foils because lift was no problem and Ive made it with a curved leading edge to accomodate a variety of ‘theoretical’ water entry angles.

The greatest problem has been keeping the foil submerged,so I have plan to do a curved foil that covers a range of depths rather than a flat foil at a fixed depth. But I will test this ply foil first and see what happens.

39

So Ive been riding this setup for the past week and its a lot beter than the first one. About 7/10 overall.

[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/May09022sml.jpg[/IMG]

An accepted hydrodynamic theory is that a submerged foil will lose power at about the same depth as the chord and in this case its a blessing because the last foils I used had a small chord and they trimmed close to the surface and often popped the surface very quickly and lost power.    But with the bigger chord it sits deep and doesnt want to travel up and break the surface. It loses some power when it breaks the surface but thats when I intentionally pop little airs off the backwash. The longer chord is a lot more stable in pitch control.

[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/May09019sml.jpg[/IMG]

 It has a lower total area of 185, down from 230 of the double foils before but the smaller foil still planes easily,not as quickly as the larger foils but it works well on anything with  a 2~3 foot face or over. The smaller area does limit how far it will drive out on the face but it is more manouverable and stable.

 The last foils had a straight leading edge but quickly lost power when I turned the board along the wave. The new foil has a rounded leading edge which I guessed might keep a wider range of edge facing the flow and it did seem to keep the power steady, it now turns with a familiar 'surfcraft' style. Bottom turns, cutbacks , little reos off the lip all feel predictable.  [IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/May09021sml.jpg[/IMG]

I caught a tube today and theres a massive power surge from the rising water within the wave when I got closer to the tube, it rides a sloping wave easily but I think the basic shape of a flat plate submerged with the wave isnt the right shape to deal with the huge increases in power that form as the wave changes shape. The ply foil is taking a beating from the force of the turns too.

 I dont know where to change the design next in order to go forward.......

 

 but i would guess more vertical surface to give more drive ( but I can already keep up with a longboard at the moment).

 I think also a curved foil of some description... but I havent a clue what shape. Maybe keep increasing the chord and roll the sides down like wings ...?? Like a cuttlefish or an upsidedown Space shuttle ?

I'll go back to polycarbonate foils again or some other kind of plastic.

 I'll keep the curved leading edge too, it works really well so I'll stay with that theory and put it into the next shape somehow.

 Any suggestions would be most welcome.

. ...... 

40

Hey surffoils,

I have to say you’re blowing my mind, and I like it! You’re leading the way to…somewhere! And I’m not being sarcastic!

Josh

www.joshdowlingshape.com