Standup Zone Forum
The Foil Zone => Foil SUP => Topic started by: sharksupper on October 22, 2017, 09:02:38 PM
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How big of waves can foils handle? Today I had a taste of some big waves.
I've been out with a torn or impinged shoulder cuff from a windsurfing mishap for a month or so, just now barely able to paddle again with a little pain and keeping my arm bent. It was killing me waiting as I had just gotten 4 solid days of foiling in before the injury. Today was the 5th day foiling and the swell was 10@12 but just couldn't wait anymore! I was too scared for the full waves at first so just worked my way up the reforms from chest, head and finally 1.5 over clean face. The biggest face I went down I keep the foil under until the bottom, just didn't feel safe on a steep drop in to even consider trying to pop it up. At some point nearing the bottom the foil's drag was pretty strong and I didn't feel like it was going to go any faster, so perhaps foils just have a natural speed limit? Like a terminal velocity? I suppose some of that was all the mast in the water too. There were doubles out there but after the 1.5 I didn't feel like it was really safe or smart to try at all. The super cool thing was after they broke there were huge long and low swell sections which had a ton of energy to just foil endlessly, so dang fun! My board/foil took a few doubles, but there is no damage so far (2011 Naish wood sandwich Hokua with stick-on foilmount). I was actually not going to be surprised if it had delam'd or broken, the waves were big, but it's fine, solid still. Which brings up another question, what is the best way to orient the board/foil for taking a large breaking wave... for survivability of the gear?
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Boats with foils have gone nearly 100 mph, maybe more, but they all have some scheme to reduce foil area or at least angle of attack. I'd expect surfing foils to be very limited on wave size, but who knows. I would have said they couldn't be actively pumped. The numbers don't work. Or at least the simplified formulas I've been using don't. But obviously, I'm wrong. Fortunately, I'm used to that.
Big waves would probably be a great opportunity to try riding the back of the wave. Plenty of energy back there, and it's going in the same direction. You'd just have to put your mental picture of how a surfboard works aside and go for it.
The drag you're feeling is probably a turbulent drag. Drag is proportional to speed at lower speeds when the flow is smooth, but when it becomes turbulent it increases as the square of speed. That's one reason why surface-piercing foils can be difficult to shape--they need to be carefully designed and manufactured to minimize turbulence (and it's what I think is wrong with the Geezer Foil, beyond me fucking up the calculations for wing size by a factor of four!).
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I'm too lazy to Google it but I seem to remember Dave, Laird and crew were foil surfing some pretty big Hawaiian winter waves 10+ years ago. Bigger than anything us mere mortals would ever consider. Tow in and snowboard boots back then, but still a foil
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I'm too lazy to Google it but I seem to remember Dave, Laird and crew were foil surfing some pretty big Hawaiian winter waves 10+ years ago. Bigger than anything us mere mortals would ever consider. Tow in and snowboard boots back then, but still a foil
Right, they were tow in foiling in huge waves at Jaws. A big, thick foil will work well at lower speeds but can't handle the speed of a big wave where you want to use a thinner, smaller foil. I would say with the right setup there is no max wave size for foiling.
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Got it, so basically the newer, thicker, easier to use, slower speed foils aren't really designed to go super fast. Perhaps as wave size/speeds go up you have to go with a foil made to be efficient at those speeds. Makes sense. Maybe you could switch to a kite foil or something meant to go faster. That also explains why they tow in, as the minimum flying speed would be higher with a faster foil... besides the fact that it's just harder to get into bigger waves of course.
Safe to say I found the speed limit of my foil, and I'm happy to not go faster for the time being! My crashes at speed are already pretty spectacular, per my friends comments, lol! So my Lift 170 surf foil is good to somewhere between head and head and a half, but can go as low as knee to waist. Pretty good range. With regular surfing I'd be switching boards between those two wave size ranges for sure.
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It also depends on where you are on the wave, if you stay on the shoulder and avoid the really steep parts of the wave, you can ride some pretty big walls, like Jamie Mitchell and Konrad Bright in this video on a Kai Foil.
https://youtu.be/x4VBzsOqgIM
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The drop is giving me problems on my Takuma foil. I get too much speed when the waves are bigger. At max speed the line between pearling and launching is tiny. Reminds me of kiting the LIquid force fun foil, all sorts so control until you get close to top speed, then the slightest mistake and off you go. If I can hang on through a few seconds of too much speed after the drop, I'll can have a great ride, but the dropping in seems like the limiting factor, for me, ...so far.
It'll be very interesting to see how the good riders figure out how to push the size limit for paddle in foiling.
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lift also increases as the square of velocity, so the foil that's just supporting your 190 pounds with ideal AOA at 5 mph is giving you 270 pounds of lift at 6 mph and 340 at 7mph. You control that lift with AOA, but the more excess lift there is, the touchier the control is.
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How big of waves can foils handle? Today I had a taste of some big waves. . . . .
It was killing me waiting as I had just gotten 4 solid days of foiling in before the injury. Today was the 5th day foiling and the swell was 10@12 but just couldn't wait anymore! . . . . .
Safe to say I found the speed limit of my foil, and I'm happy to not go faster for the time being!
Put this all in context. If some kid came up and said:
"I learned to surf last week and paddled out in 10 ft @ 12 seconds and my board didn't work. I think I need a new board."
If I am reading this correctly this was your 5th session on the foil. Which means that you, like the rest of us, are a total beginner.
Give it time. It took 20 sessions for me to learn the subtle control of the front foot. Heavy front foot then only fly once down the wave. Lots of face plants to come. After 30 sessions + I have 1 session on 2X plus sized waves, up to 15 feet. I would take off and GO FLYING (Vertically). As you suggested.
However that was my first session.
Haley Fiske was out last weekend at Mavericks. Similar report. He was attempting to take off on the periphery. He could fly easily, way easier than expected on his Kai foil for his 230# of weight, then he would light up and GO FLYING (Vertically). However this was his 1st attempt.
Speed is the Issure. To put this into perspective: The Kai GoFoil will fly anywhere from 10 to 14 mph. The fastest I have gone as measured using the TRACE UP was ~ 24 mph. A typical 'Very Fast' feeling on the GoFoil is ~ 22 mph. I have caught waves at Mavericks and measured as SLOW as 22 mph. The fastest I have ever measured at Mavericks was 32 mph. The moral of the story is that going straight on huge waves may be possible. To Robert's point if you can get to the shoulder you may find Nirvana. However going down the line will increase the speed.
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How fast can the GoFoil 'Fly'?
Here is Kody Kerbox on his GoFoil Kai model behind a boat. People with more ski experience may be able to estimate the speed he is going when crossing the wake @ 0:20.
It appears much, much faster than 20 mph. He is also light, lighter than most of us. It looks like a handful but it gets the imagination going.
www.youtube.com/watch?v=gabUozHNddM
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Cody is amazing.
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These waves were pretty big.
Kai was towed into these waves we're not sure what wing he was flying on. This was south of Mavericks on a big day:
https://www.youtube.com/watch?v=a4tk-Xnuxj0
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Heavy front foot then only fly once down the wave.
Tried this today and it worked great. I had to put what I think was all my weight in front of the spot I usually have my front foot, then gradually slide back until I was slow enough to give a little hop and fly away.
Thanks for the tip.
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Tried this today and it worked great. I had to put what I think was all my weight in front of the spot I usually have my front foot, then gradually slide back until I was slow enough to give a little hop and fly away.
Thanks for the tip.
Yup! You can catch the entire wave HEAVY FRONT FOOT.
It's awkward but will allow you to ride the wave similar to nose riding a long board. The only sad thing is you feel like you missed the wave's punch.
Regardless you can make the drop and then potentially fly later. With the foil its less about the drop and more about the glide.
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Kai is still pushing it.
Here are some shots from Maui fresh off his Mavericks sessions at the beginning of the week.
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Shame they are only good for small waves.
There's really no rule book, that's the thing I'm seeing daily with you guys foiling. Every time something is stated as absolute fact, someone blows it away. It's cool to watch this grow.
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As Beasho said speed is the issue and increasingly smaller foils are capable of higher speeds, once you’ve got the speed ,control is the issue and for larger waves it could involve a setup with an overal length of several feet. Even a short mast foil set at nose and tail of the board.
Everythings possible with an open mind.
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Guys don’t use surf foils in fast waves. I was told Kai uses kite wing. Heck, even here in Florida, guys use kite wings in waves of any power.
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That’s the thing about the highly foiled and cambered foil, they give excellent lift in low lift situations but as the power of the wave increases it’s not important to look for speed but for control.
Better control at speed comes from Less area, a flatter foil, increase the chord for pitch stability by combining front and rear foil into one design.
Laird has half the equation because he used the tow in boating foil that’s a foiled but flat aluminium design. You notice that despite his speed he carefully watched his AOA.
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This pic of Kai is a really good example of what happens at speed , look how high the foil is and the way he is pushing his knees forward to keep the foil down , it's incedibly hard to shift the front foot. The faster you go you keep creating lift , that's the problem. The other issue is wind any offshore breeze jacks the board adding to the problem so the board has to be small to reduce this effect. We were maxing out on the Gofoil & Naish at 20 mph on larger waves but now holding 30 mph. We simply got better at riding them. Flatter low aspect foils have their advantage but when you crack the surface they slam hard , the bigger curved wings can be held near the surface gurgling and suppress the touchdown pressure, keeping you on your feet.
It's way too early to put a maximum speed on foils yet as riders ability just keeps progressing and so do the foils and boards. IMHO 50 mph is just around the corner.....
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This pic of Kai is a really good example of what happens at speed , look how high the foil is and the way he is pushing his knees forward to keep the foil down , it's incedibly hard to shift the front foot. The faster you go you keep creating lift , that's the problem. The other issue is wind any offshore breeze jacks the board adding to the problem so the board has to be small to reduce this effect. We were maxing out on the Gofoil & Naish at 20 mph on larger waves but now holding 30 mph. We simply got better at riding them. Flatter low aspect foils have their advantage but when you crack the surface they slam hard , the bigger curved wings can be held near the surface gurgling and suppress the touchdown pressure, keeping you on your feet.
It's way too early to put a maximum speed on foils yet as riders ability just keeps progressing and so do the foils and boards. IMHO 50 mph is just around the corner.....
Looks like Kai is on his go-to 3'8".
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This pic of Kai is a really good example of what happens at speed , look how high the foil is and the way he is pushing his knees forward to keep the foil down , it's incedibly hard to shift the front foot. The faster you go you keep creating lift , that's the problem. The other issue is wind any offshore breeze jacks the board adding to the problem so the board has to be small to reduce this effect. We were maxing out on the Gofoil & Naish at 20 mph on larger waves but now holding 30 mph. We simply got better at riding them. Flatter low aspect foils have their advantage but when you crack the surface they slam hard , the bigger curved wings can be held near the surface gurgling and suppress the touchdown pressure, keeping you on your feet.
It's way too early to put a maximum speed on foils yet as riders ability just keeps progressing and so do the foils and boards. IMHO 50 mph is just around the corner.....
Good point. Rush Randle and Laird were using sit-down hydrofoil set-ups from Sky Ski on a wakeboard with snow board bindings and getting towed in. We push the mid-30 mph's on these set ups (sit down) when cutting across the wake etc. Guys have gone 50+ behind a sea plane- point is, the wings are thin and ready to go!
Interestingly enough, currently working with Dave Daum in making a set-up to river foil surf at 3-5 mph's. The key here is to keep charging on both ends of the spectrum!!