Standup Zone Forum
The Foil Zone => Wingsurfing, Windfoiling, Wingfoiling, Wing SUP => Topic started by: burchas on June 01, 2022, 07:52:36 AM
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I hear a lot of negative feedback on forums but some very popular designs include tail rocker.
Starboard Take-Off, SIC wing boards, North Seek (by way of Indiana Wing board), PPC Soar come to mind.
Any deep thoughts on the subject?
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Almost every foil on the market is designed for a mount point that is flat to the deck surface. Tail rocker throws off those angles and adds an angle that the foil (generally) wasn't designed for. Tail rocker will make the board ride nose-up if the foil isn't shimmed or otherwise designed to accommodate the angle.
You can always adjust for the tail rocker with a baseplate shim, but I would rather start with a flat mount surface and minimize shimming wherever possible.
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Do you mean tail rocker, or a “tail kick”? Big difference. I’m opinionated about tail kicks serving no purpose whatsoever except to slow boards down. I can hear and see my tail kick board sucking water up while I’m pumping onto foil and can feel the lack of that drag on my straight tailed board which works better at near foiling speeds.
Tail rocker is different. My home shape is absolutely flat in the back half. I think it’s the fastest design for getting on foiling but it has drawbacks and my next board will have slight tail rocker in the back half. This is because I use a Tuttle box and can angle it how I like, but angling the foil slightly down will make the board ride level at speed.
The tail rocker is more for starting, pumping into or with waves on crazy sea state can be really hard. Once the board starts moving, the tail lifts so much it pushes the nose under little waves and you fall. Having some rocker would allow you to angle the board up slightly and mitigate this issue. Not sure how it would affect balancing while slogging, maybe positively?
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I now use two different boards for SUPfoil and WINGfoil. I designed them both.
My wingfoil board has absolutely no tail kick and less than a degree of rocker on the back half. It gets on plane super fast and comes up off the water smoothly. but it is completely terrible to SUPfoil on waves. The back of the board sticks in the water when catching the wave and won't allow me to bring the nose up quickly to get on foil on the drop. It really is bad and nearly un-rideable.
My SUPfoil board has a bunch of tail kick with no rocker on the back half - and gets on waves super easily - one big paddle pump as the wave picks up and off we go. It wings ok, but doesn't come up to speed nearly as easy.
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I say no to both. This is what shims are for. With shims you can have more than one foil.
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Ditto what Stella said. Tail rocker on a wing board seems like a pointless carryover, like an appendix that doesn't do anything useful and might cause problems. The SIC manta I bought has quite a bit of rocker. I had to shim the crap out of the base plate to get it to work.
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Well it depends on what you want the board to do and your level of experience. If you are a beginner and riding a relatively big board where you generate board speed to get up on foil you want a board with no tail rocker to help this process. But once up on foil you will find that the board tends to ride nose down and is uncomfortable to ride as there is not enough front foot pressure.
If you are more experienced and riding a smaller board where you pump the wing and foil to get up on foil then you will be much less concerned about the behaviour of the board transitioning off the water and far more concerned with the attitude of the board while flying. You will want some tail rocker to have the nose of the board ride a bit higher to balance your feet out to get enough front foot pressure. This is more accentuated as you begin to ride faster and faster and generate more and more lift from your foil. In that scenario you need the nose up a little to get a nice balanced foot pressure. We learnt this lesson on kitefoil boards a while back. Have a look at the rocker on a kitefoil raceboard. Its quite a banana, but feels very comfortable to ride at speed. Compare that to a SUP foil board which is generally quite flat rockered and often rides uncomfortably nose-down. I have built a series of boards from the very beginnings of the sport transitioning from 115 to 100 to 85 to 65 to 60 to 58l. I have added progressively more tail rocker as my experience level increased except for the last 2 boards where i settled on the same more pronounced rocker line. Increasing the rocker absolutely did not make any meaningful difference to takeoff once I was past that beginers stage of using board speed to get on foil. And that is irrespective of HA or low aspect wings. Have a look at what Ken Adgate is producing for the high-level winger in the Bay area and you will see where this is heading. If a board is properly designed it should not need to be shimmed. The same goes for tail wing shims. Its just an excuse for poor design.
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Kalama tail beats them all.
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You will want some tail rocker to have the nose of the board ride a bit higher to balance your feet out to get enough front foot pressure. This is more accentuated as you begin to ride faster and faster and generate more and more lift from your foil. In that scenario you need the nose up a little to get a nice balanced foot pressure.
I respectfully disagree with some of this. If your foil is properly positioned and set up you should be able to balance foot pressure with a flat tail board.
Doesn't KA design all his boards with tuttle boxes where you can adjust the angle of the mast (I haven't seen his boards in person - so I am not certain of this)? If thats true, then tail rocker doesn't matter since you can counter it with the angle adjustment (exactly the same as a shim).
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I’m not aware of any way to adjust the angle of a Tuttle mast once a board is already built. I was asking Ken the other day about his tail rocker and he said that you need some so at speed you are running level and not nose down. I’m going to try 2 degrees or so next build.
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When I was heavy into making board last year and couple years prior, I'd measure up any board I got my hands on. Most surf and sup foil boards had some tail rocker from the boards mid-point, some a lot more than others. As it was explained to me, this gives the board a more "nose up" feel, like riding a snowboard in powder. Watching a surfer on a no tail rocker and low nose rocker board, it can look like the board is angled down sometimes, which gives the wrong feel. I think this is more for surf foil, where you paddle with the nose out and board angled a little up -- so the foil fuselage is horizontal/level at this angle. But for sup foil, you paddle the board flat, so want minimal or no tail rocker to achieve same thing. Wing foil perhaps the tail rocker could help with take off, getting the angle at the top of a pump -- but that is probably more about low aspect pumping style (up and down) vs high aspect (more like a jet taking off). So I suspect that may be part of this, the trend of HA foils has made boards more likely to need flat tails, same with the no tail kick trend (ginxu notwithstanding).
Latest board I checked out is the new Armstrongs, with their Forward Geometry. Designed for ride further forward. The foil mount is close to the center of the board. The tail rocker is extreme -- like a surfboard. That's completely opposite of what most boards are now and what most of you are saying, yet one of the most popular boards in the world.
So...how to reconcile that 180 degree difference in design opinion? The cynic in me says one logical answer is that it makes an unsubstantial difference either way. Subtle differences in the ride, good or bad, for different conditions ... but fundamentally both work. Particularly as when you're powered up the ease of take off is completely irrelevant, you pop up in 1 second on first pump. As well, for intermediates and up -- I now often spent 30-60 minutes at a time without a touch down or wipeout, so who care about bottom shape when I am in the air? A lot of this stuff is shiny fishing lures to attract fishermen rather than fish. ::) :o ;D
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Guys I know with the new Kalama tail say it's a game changer and they can get up on foil easy even in flat water where on other shapes they could not.
Tail shims are all about fine tuning a foil to a riders style and to match the conditions or wave size/power. The best guys on ML foils shim the tail when need be, the older unibody design had a shim in between the mast bolts to bend the fuse and change the angle of the tail.
Two bolt tuttle masts are easy to shim (haven't tried the 3/4 bolt tuttle masts):
https://www.youtube.com/watch?v=tP7Q9-2p-gI
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I think the dual-stage tail rocker on the Starboard Take Off is really interesting. Could be a way to get the best of both worlds.
I copied this on my new board.... which is still getting glassed.
(https://i.imgur.com/M1zjRDn.jpg)
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I’m not aware of any way to adjust the angle of a Tuttle mast once a board is already built. I was asking Ken the other day about his tail rocker and he said that you need some so at speed you are running level and not nose down. I’m going to try 2 degrees or so next build.
Actually, it's fairly easy to adjust the angle of a tuttle with shims, it's the only thing you CAN adjust unless you change the fuselage-to-mast attachment point.
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...The SIC manta I bought has quite a bit of rocker. I had to shim the crap out of the base plate to get it to work.
Bill, I'm curious as to the conversation that took place when you told that to Mark... He is an Axis rider if memory serves.
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Almost every foil on the market is designed for a mount point that is flat to the deck surface. Tail rocker throws off those angles and adds an angle that the foil (generally) wasn't designed for.
Certain design elements addressed this issue:
- Dropped concave deck parallel to mount point.
- Center bottom channel parallel to the deck
- Both of the above combination
- The step bottom mount point shown on the new Starboard Take-off and some other designs.
With that in mind, same wing board design, one with tail rocker the other without. Pros Vs. Cons
As mentioned, some popular designs like the Armstrong, F-One and Bill's SIC Manta ;) wing boards have considerable amount of tail rocker.
It's a deliberate design choice that , in theory (I assume they tested it), should work well with all their foils offering.
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Tail-rocker is a conundrum - to get up on foil your actually want a displacement design which is always more efficient with some rocker and once you are up on foil you want the slippery, skippery feel of a planing hull for touchdowns. I agree with Jondrums observations except that a flat rocker board launches quicker when winging - that I find only potentially true on shorter sub 5'0ft wing boards. On longer wingboards the same trouble Jondrum describes becomes apparent - especially if you are trying to pump board up.
Kalama's board have zero rocker from what I can see along the centerline from the middle back - he solves the conumdrum with his extreme V in the tail which gives plenty rocker along the outline.
My take is that you need some rocker, especially on SUP's and the reason people think flat rockers work on wing boards is because the power on hand allows you to overcome the initial tail drag apparent when you try and pump up - once you overcome this drag (with the help of the wing) the board releases quickly and pops up on foil - it feels efficient, but it actually isn't.
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The 2022 Axis Froth 45L (4'4" X 23") has tail rocker. The tracks are way back compared to most boards: 3" from the tail of the board. When I place a straight edge on the tracks, it has about 5mm of tail kick and 1.5cm of tail rocker measured at the mid point of the board. I do prefer the way it rides compared to a board with zero tail rocker (This is on Axis carbon 86cm mast and HPS 830). The ride angle is more comfortable (it's not nose down). Easier to recover from touchdowns. I can't say that it starts as easy as a same sized zero tail rocker board because I don't have one to compare to. But compared to a 71L zero tail rocker board that has a tail bevel, the little Froth foils up easier....not easier when it's under water obviously, but easier once on the surface.
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Another Kalama inspired tail. This is Kane. My crystal ball says the rest of the world has these in production for the 2023 season.
(https://live.staticflickr.com/65535/52124016993_5ce86189c9_z.jpg)
(https://live.staticflickr.com/65535/52124032808_5f08dba868_z.jpg)
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*****SHIM SHAM*****
Why is it that folks who shim feel like they need to inject shim sham talk into every thread?
The thread is about tail rocker which is a board shaping discussion. Please take shim talk to some other thread that I won't read. :)
Mkaay? Thanks
*****/SHIM SHAM******
One thing I think about the Kalama tail end, being tall and V Shaped on the new boards, is that they cork and then uncork easily, not sticking to the water. As you pump down you are pushing more volume deeper with less effort, then the volume corks the tail back up with less stick to the water.
I also have always felt that the longer the flat surface(even behind the foil box) the more glide in general(flat water). DW talks aboot this also.
-red
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Because tail rocker in the fin box area leaves the foil tipped at an angle. If you want your foil to be parallel to the deck then it's an issue to consider. m'kay. Were you scared by a shim as a child? Oh, and pushing more volume deeper with less effort? I'd suggest a quick review of high school physics.
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Pono, I get that, but It looks like the discussion was around the tail section rocker not the foil box location. Granted, they are close in proximity. Maybe I am missing something or interpreted the first incorrectly. I thought we were talking about flat bottom where the foil box is located and then the bit after that towards the tail. The bit after the foil box being the subject here. "Tail rocker" not foil box rocker.
-r
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Been doing flat tail rockers since my first foil shape attempt long ago....
(https://i.imgur.com/FGSa4xZ.jpg?1)
Started going no tail kick last year after DW made great sense on why we don't need them...
(https://i.imgur.com/UmhKylS.jpg?1)
Found that chines all the way back out the tail made it tippier(?) and more work than was comfortable in windy/whitecap days so added some flat to the tail...
(https://i.imgur.com/njrH4nr.jpg?1) (https://i.imgur.com/Z1FWFhT.jpg?1)
...that removed all of that. Love this board!
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Pono, and now you have me thinking more about volume. No I am not a physics expert like you sir.
So then, in my lesser brain, I imagine pushing a V shaped wedge down into the water takes less effort than pushing a flat shape (With the same volume).
no?
-r
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Been doing flat tail rockers since my first foil shape attempt long ago....
(https://i.imgur.com/FGSa4xZ.jpg?1)
Started going no tail kick last year after DW made great sense on why we don't need them...
(https://i.imgur.com/UmhKylS.jpg?1)
Found that chines all the way back out the tail made it tippier(?) and more work than was comfortable in windy/whitecap days so added some flat to the tail...
(https://i.imgur.com/njrH4nr.jpg?1) (https://i.imgur.com/Z1FWFhT.jpg?1)
...that removed all of that. Love this board!
Califoilia, Looks awesome. Are you able to Stand up Foil Surf it, or Wing or both?
-r
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Pono, and now you have me thinking more about volume. No I am not a physics expert like you sir.
So then, in my lesser brain, I imagine pushing a V shaped wedge down into the water takes less effort than pushing a flat shape (With the same volume).
no?
-r
Not Pono, but yeah, that was my thought(s) with the more "Kalama styled" pin tail on my latest board above.
Like you, not a "physics expert", but it seems to work. This little board (5'1x27x102) paddles well and catches waves much better than my same-sized previous board with a kick tail, and more like my 6" longer 5'7x27x103 board with a kick in it also.
Califoilia, Looks awesome. Are you able to Stand up Foil Surf it, or Wing or both?
-r
That's a sup foil board that I have tried winging with, but find that the boxes and strap are a little too far forward to make it the perfect wing board.
So I use the flat tail board w/the chines out the back for winging, since it's boxes are about 3-1/2" further back than where I want them for the surf...
(https://i.imgur.com/5WfMMg9.jpg?1)
...the screws sitting on the board is where I'd typically have the front of the baseplate in the surf, even a little further forward depending on wing choice for the day. The chines out the tail are not a problem with this board for winging, since I'm not standing around trying to balance waiting on a wave the same way I'd be doing it in the surf.
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Kane commented.
https://www.instagram.com/p/CebW8zYumkR/?igshid=YmMyMTA2M2Y=
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Pono, and now you have me thinking more about volume. No I am not a physics expert like you sir.
So then, in my lesser brain, I imagine pushing a V shaped wedge down into the water takes less effort than pushing a flat shape (With the same volume).
no?
No.
Not exactly quantum physics guys, it takes one kilogram of force to displace one liter of water (approximately) for any object floating in water. You already know this from considering the displacement of boards that can float you. Whether the force is applied by your weight, or by jumping up and down, one kilogram of force will displace one liter--it doesn't matter if it's pyramids, spheres, boxes, or a spaghetti noodle.
Here's the basic shim issue as applied to the SIC Manta--required two thick shims and the mast is still tilted back a little and the fuselage is still not quite parallel to the natural waterline. I'd add a third shim but then I'd need to use wizard hat hardware or risk cracking the tracks. I asked Mark why the board had so much tail rocker. He just shrugged and said "it's OK for surfing, but yeah, we don't do that so much anymore."
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Pono, I get that, but It looks like the discussion was around the tail section rocker not the foil box location. Granted, they are close in proximity. Maybe I am missing something or interpreted the first incorrectly. I thought we were talking about flat bottom where the foil box is located and then the bit after that towards the tail. The bit after the foil box being the subject here. "Tail rocker" not foil box rocker.
If you are focused only on the area past foil box, then you are talking about tail shape, tail kick, tail chines, etc. Rocker is the curve on the bottom of surfboard, from the nose to the centre line, then from there to the tail. Surfboards are curved like a banana. Foil boards vary, some having both nose rocker and tail rocker, some just nose rocker from the midpoint or a point forward of it, some being flat from midpoint through the foil boxes, others have substantial curve through to the tail (rocker). The new Armstrong board being the most extreme example I've seen recently for extensive tail rocker...a couple inches from I recall. The Fanatic sky boards had only a little, maybe half inch, with more for the shorter boards I think.
To measure rocker, hold a 6' ruler from the midpoint back, you may be surprised how many foilboards have some. And yes, shims are for people who don't want any tail rocker, so shimming the back bolts makes it flat/neutral from the midpoint.
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Kane commented.
https://www.instagram.com/p/CebW8zYumkR/?igshid=YmMyMTA2M2Y=
Funny how Kane's comment is so relevant to this thread: "Touch of tail rocker and it’s super forgiving!"
The Kalama inspired bottom I've used on my last board is the reason for the thread. Although the secondary rocker along the bottom outline help in shaving all the volume from the tail I feel that I could have used some tail rocker.
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I think it's worth mentioning (and to give him some credit!) that Patrice has already put this design feature into nearly all of the 2022 Gong boards, having first appeared on last year's Lethal.
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DW, what have you found are the benefits to the Kalama tail for winging? Does it help starting or is it more for preventing speed loss for touchdowns? Kalama says elongating the flat section, but why go so narrow in the tail on the flat part?
I’m making a new board for a couple reasons, one of which is that mine likes to nosedive when pumping up in chop and jumping.
My use case is small foils that force my board to fully plane to get going. I feel the board plowing and with enough wind or max pumping it then goes “pop” I’m up and planing. A couple pumps on a plane and I’m fast enough to lift off (600 an 800 cm foils). My thesis is that a flat sheet of plywood is ideal, but I must make concessions for chop and touchdowns. More nose and a little tail rocker might do it. I just don’t see how the Kalama tail and chines would help?!
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DW, what have you found are the benefits to the Kalama tail for winging?
The long story…..
It started with an opportunity to SUP his 5’2 x 28. The force to pull the blade was half any other SUP. Clearly the concept of allowing water to flow around, and off the back, with the least amount of drag worked.
Next was to try the concept winging. My thought was if less paddle force, then less wind force needed. In testing, the concept gets under motion earlier, AND more efficiently in choppy seas or confused currents. While the full wide planing bottom board, often needs a cleaner patch of water surface to get onto plane.
It is just an all around better board and easier to get on foil, even with fast foils.
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I think it's worth mentioning (and to give him some credit!) that Patrice has already put this design feature into nearly all of the 2022 Gong boards, having first appeared on last year's Lethal.
To my eye, the Gongs have more in common with Kalama’s prototypes before he went full point at the back.
This version never went to production, but we see many others went to production with something similar.
https://www.instagram.com/p/CaD7517LJ2-/?igshid=YmMyMTA2M2Y=
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probably worth reading through this thread from 2 years ago
https://www.seabreeze.com.au/forums/Stand-Up-Paddle/Foiling/early-release-experimentation?page=1
This was from before Kalama hit on the iconic triangular tail concept. On the second page there is an iteration that the original poster says is even better than the first try.
As always, we are debating about topics that depend so highly on how we want to ride and which conditions we have - so it isn't surprising that we disagree often.
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I think it's worth mentioning (and to give him some credit!) that Patrice has already put this design feature into nearly all of the 2022 Gong boards, having first appeared on last year's Lethal.
To my eye, the Gongs have more in common with Kalama’s prototypes before he went full point at the back.
This version never went to production, but we see many others went to production with something similar.
https://www.instagram.com/p/CaD7517LJ2-/?igshid=YmMyMTA2M2Y=
I'm not saying they're identical, but there is more than a little resemblance between the tail on the KD board on the previous page, and the current tail of the Mint, for example. (If I was vaguely internet literate, I'd post some pics.)
They're all variations of a theme, which is not straight tail (that's is so 2021 🤪), but a displacement, low drag style. I'm curious which other production boards have also got that?
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They're all variations of a theme, which is not straight tail (that's is so 2021 🤪), but a displacement, low drag style. I'm curious which other production boards have also got that?
It certainly look that way. Maybe because Kalama has more clout or maybe his execution is just better that put him as the poster boy for this theme.
F-One incorporates something similar in some of their rocket boards, tail rocker however, is in all of their boards. I believe they got the right idea.
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Things are changing so fast... We have all joked, "That's so 2021" about one thing or another in this crazy fringe sport. But now that I purchased a 2022 Axis Froth (and by the way I think it's awesome) about a month ago and it's already outdated I guess I have to start saying my new beautiful board is so 2022? The year is not even half over yet! Will I be considered a Luddite if I am still using my 2022 gear later this year?
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Kalama is a straight tail. A planing flat out the back tail. A planing bottom that allows water to flow around the back to improve water release.
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I'm not subscribing to a certain magic shape or design attributes. Seems like the level of execution and implementation has more impact than a specific feature.
I've been riding SlingShot Wing Raider 4'10" x 27" @90L back to back Vs 2022 Fanatic 5'4"x26@95L. The WR pumps better and releases faster than the Fanatic.
stability is on par with the Fanatic comfortably schloging and knee starting from around 8knots and.
After seeing the 2022 Fanatic shapes on paper I thought they would perform like a Dwight board since the shape looks very similar.
Riding one of Dwight's FSM 4'10"x25.5@85L in marginal conditions, the difference in performance and stability over a Fanatic of a similar size was noticeable,
it's more on par with the Wing Raider. Two slightly earlier versions of the FSM didn't have quite the same magic.
The bottom of the Wing Raider is a double concave at the nose to a single concave all the way through the back. The wetted surface is under 4' long on 18.5" at the widest point
Looking at design features of the Wing Raider like a huge Kick tail and bottom concave, after spending enough time on the forums, you'd think the board literally sucks. Not the case.
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Burchas... thanks for sharing the Wing Raider photos.
It's an interesting design. And helps confirm my theories about the physics going on here. The key is to prevent large volumes of water from bending around big corners to fill a pressure void area. Because the WR has a low angle step with low angle side corners, water can bend around easily, thus reducing drag in displacement mode.
I'm cracking the whip on my glasser as hard as I can, so I can get my board this week.
My take on how to solve this problem is different than anything else I've seen. In total of course, as I'm blending a number of ideas into one design.
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To summarize, how I understand this, is it's about speed. Can we agree on the below 2 things?
1. ~ 0-6 mph - A more round canoe style is easier to accelerate at these speeds. Rounded edges everywhere or deep chines, tail kick, canoe stern.
2. ~ 6-10mph - Hard edges in the tail area are better as the water will release cleanly at planing and near-planing speeds.
- A foil that gets going at 6mph has no benefit to #2 designs and should be simply #1.
- A foil that needs 10mph needs to get going should be #2 design, however, it will be a bit harder to get initial speed.
Foil takeoff speed varies between rider weights and foil characteristics.
My use case is that I'm not willing to give up planing ability to make things better at the low speed. I can feel things are hard to get going at low speeds on my #2 board, but if there is wind to take off, I can pump through this. However, I hate the feeling of getting within 1-2mph of foiling speeds pumping like mad and having my board "suck" at the tailkick. Maybe I'm just a fat guy with a tiny foil. :P
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To summarize, how I understand this, is it's about speed. Can we agree on the below 2 things?
1. ~ 0-6 mph - A more round canoe style is easier to accelerate at these speeds. Rounded edges everywhere or deep chines, tail kick, canoe stern.
2. ~ 6-10mph - Hard edges in the tail area are better as the water will release cleanly at planing and near-planing speeds.
- A foil that gets going at 6mph has no benefit to #2 designs and should be simply #1.
- A foil that needs 10mph needs to get going should be #2 design, however, it will be a bit harder to get initial speed.
Foil takeoff speed varies between rider weights and foil characteristics.
My use case is that I'm not willing to give up planing ability to make things better at the low speed. I can feel things are hard to get going at low speeds on my #2 board, but if there is wind to take off, I can pump through this. However, I hate the feeling of getting within 1-2mph of foiling speeds pumping like mad and having my board "suck" at the tailkick. Maybe I'm just a fat guy with a tiny foil. :P
You’re spot on. That’s why I didn’t make a Kalama clone a year ago. It wasn’t until a friend let me try his, then built one for me, that I discovered it does both in one. It’s a planing bottom, no tail kick. The pinned tail further reduces drag. The pinned back makes it work like it has rocker, without having it. It just does everything better. Easier for beginners, easier for racers. Try one.
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JohnnyTsanami- How much you weigh? What 600 and 800 cm2 foils are you using?
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Calling back to the "push volume down with less effort" (needed to clean that up lol.) The thing about pushing down is that you won't reduce the effort for the same volume, that's fixed. But your mind says that the angled wedge should require less effort at the same volume. This issue is that the wedge will always be less volume at comparable dimensions. 2 liters takes n amount of force to sink/displace. This is what Pono was calling out. Additionally if they were the same volume you might assume the wedge might save effort because of drag but that would be minimal in 4-6" pump travel. Califoilia isn't wrong with that design or his feel. I'll bet it does pump easier than a blocky tail, because there's less volume back there.
Moving to Kalama best of both worlds. As usual DW explains it. Of course it's a #1 & #2 in one. The canoe shape gives you #1 low speed and the hard edges and bottom give you #2. Cool stuff.
I feel better now because people say all my boards are a big number 2. (I had to)
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JohnnyTsanami- How much you weigh? What 600 and 800 cm2 foils are you using?
170, Mike's Lab
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Since I have Armstrong boards I’d previously thought about how they and the kalama shape are different ways to achieve the same ends. Moving the tracks forward allows the tail rocker to be gentle enough to not grab the water when touching at speed like a flat tail, but still get near or at the surface when slogging, so you aren’t making an eddie. I’ve never sup’d either or used a kalama so idk how they compare in either respect. I’m sure the kalama is a faster paddler…. Although I think if I made a kalama rip off I’d fade in a release edge (maybe 0.5cm deep) towards the back end, so water really can’t get sucked around the angle when touching.
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ML- ya that's what I thought. 800 and 600 is all the buzz right now in the Mike's Lab world. Are you using that super tiny stabilizer? I think it's too small. At least for me. Makes the foil feel really unstable and porpoises. Wonder why they came up with that size? 32 cm. It's smaller than the stabilizer on my Bullet 3 kitefoil. And I wish they would make a big brother to the 800 for light wind course racing with a 100cm wingspan. That would be really great. Sorry off topic but relevant.
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Dave started building those boards for prone foiling and then started doing a lot of wild variations to test the concepts. He made a ridiculous number of prototypes, some of them very strange--like the super-ling prone barracuda-skinny board he was playing with probably around January. Then a couple of people tried them wingfoiling, and then incredibly quickly--it seemed like less than a week or so later there were all kinds of Kalama weird tail, skinny boards winging and surf foiling or doing the flatwater pop-up classes with Jeremy Riggs. They multiplied like bunnies on Maui. I've only seen a few downwind foiling here in the Gorge.
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Tail-rocker is a conundrum - to get up on foil your actually want a displacement design which is always more efficient with some rocker and once you are up on foil you want the slippery, skippery feel of a planing hull for touchdowns. I agree with Jondrums observations except that a flat rocker board launches quicker when winging - that I find only potentially true on shorter sub 5'0ft wing boards. On longer wingboards the same trouble Jondrum describes becomes apparent - especially if you are trying to pump board up.
Kalama's board have zero rocker from what I can see along the centerline from the middle back - he solves the conumdrum with his extreme V in the tail which gives plenty rocker along the outline.
My take is that you need some rocker, especially on SUP's and the reason people think flat rockers work on wing boards is because the power on hand allows you to overcome the initial tail drag apparent when you try and pump up - once you overcome this drag (with the help of the wing) the board releases quickly and pops up on foil - it feels efficient, but it actually isn't.
I think your analysis makes most sense. It's certainly consistent across the board and not necessarily following trends:
My 5'10 is pretty much straight tail - zero rocker with small cut away last 2inches. I don't like the no rocker feeling, a 5'10 board paddles slow as is, and when tail get's lifted by wave for take off, it's sticky, sticky, sticky, until all hell breaks loose and the flat rocker makes the board feel like it's on roller-bearings and you take off. The straight tail pushes the nose down so you have to counter that by sinking tail a bit adding to the stickyness. I prefer a more progressive acceleration and I feel the board needs a much steeper wave than what a narrower longer board would. The E3 solves the flat rocker issue by the triangular chimes in back
Trying 3 different variations of the Kalama concept including my own, I had few observations. Volume and maybe more important, surface area at the tail seems to dictate how effective is the concept when it comes to winging.
I can see how the concept addresses the water flow and release but for pumping the wider kalama tail didn't seem to offer advantage over straight tail for similar volume except for the super narrow Barracuda tail
That said, pintail for a wing board wouldn't be my choice (maybe for sinker) which bring me back to the rocker.
Reading through these comments was a throwback to the sup days when I compared the SIC Bayonet Vs Naish Maliko, continuous rocker vs 2 stage planing rocker or progressive acceleration vs explosive take-off.
The Maliko tail rocker is not completely flat but it is minimal. I think that incorporating this kind of tail rocker on a short wing board might prove more effective when initiating a pump over a dead flat section yet still effective
for touchdowns.
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Ha ha, looks like I'm not the only one convinced by Kalama's thought processes. This is my new SUP in progress too. No tail rocker and kalama tail for a SUP that needs boardspeed to get on foil. The tradeoff is a nosedown attitude in flight. I still think a wingboard needs some tail rocker for better flight characteristics but If the SUP proves to be what people are saying I will try a rockered kalama tail on my next wing board.
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Interesting observation Slyde, do you use footstraps? I can see how that reduced tail volume would demand that you be standing a bit forward when you're floating, and if you can't shuffle back a bit you'll be nose down. You could tune the foil position to flatten the trim, or perhaps experiment with your foil or stabilizer angles, but everything is a compromise since we don't have any active trim capability other than body weight position relative to the foil. The Kalama tail is designed first and foremost to move through the water easily. The really long versions made that goal clear--they comprised foiling agility greatly in favor of gaining speed quickly in a wave.
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Do any of the E3 sizes have tail rocker along the center line?
I agree with Slyde that, "I still think a wing board needs some tail rocker for better flight characteristics..."
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Interesting observation Slyde, do you use footstraps? I can see how that reduced tail volume would demand that you be standing a bit forward when you're floating, and if you can't shuffle back a bit you'll be nose down. You could tune the foil position to flatten the trim, or perhaps experiment with your foil or stabilizer angles, but everything is a compromise since we don't have any active trim capability other than body weight position relative to the foil. The Kalama tail is designed first and foremost to move through the water easily. The really long versions made that goal clear--they comprised foiling agility greatly in favor of gaining speed quickly in a wave.
Well actually this SUP will be for a foil drive so I won’t be using straps for that at least to begin with as there is quite a lot of weight movement required as you foil up. I may add a front strap as I get experienced. The design philosophy here is to have a SUP that will foil up with the least effort so that I can ride non breaking swells at my local beach on no wind days. The sandbar disappeared after the council modified some groynes so now there are no breaking waves that can be paddled in to, but the swells are still there begging to be ridden. Hence the foil drive. It seems the Kalama tail will be the best way of getting a board of this size up to foiling speed. Itching to get it on the water to try.
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I'm building my own foil drives. I'm at V 2.2 right now. I just blew my most recent folding prop into shrapnel--I need to start armoring up before I test these things--I had a chunk of the prop hit me square in the breastbone. It left a small cut and a big-ass bruise but didn't wind up stuck in my chest so I got that going for me. Time to get the props printed at shops that can do more exotic stuff, though my latest modification to my Ender printers pushes deep into exotic extruded plastic.
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I'm building my own foil drives. I'm at V 2.2 right now. I just blew my most recent folding prop into shrapnel--I need to start armoring up before I test these things--I had a chunk of the prop hit me square in the breastbone. It left a small cut and a big-ass bruise but didn't wind up stuck in my chest so I got that going for me. Time to get the props printed at shops that can do more exotic stuff, though my latest modification to my Ender printers pushes deep into exotic extruded plastic.
Thats above my pay grade.
Ill stick to carbon , foam and epoxy. ;)
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I'm building my own foil drives. I'm at V 2.2 right now.
Funny, I was just talking about this at the beach yesterday. We were discussing putting a hole all the way through the deck and mounting the battery pack longitudinally right above the foil. Heat sink would be exposed on the bottom of the board. That would make it nice and low profile and mitigate the heat and swing weight issues.
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Funny, I was just talking about this at the beach yesterday. We were discussing putting a hole all the way through the deck and mounting the battery pack longitudinally right above the foil. Heat sink would be exposed on the bottom of the board. That would make it nice and low profile and mitigate the heat and swing weight issues.
[sorry for full-on thread hijack]
I am on diy foil drive v2.1. (aka Faux Drive)
The foil drive is designed to be an add-on to an existing board/foil. The system works but the wires and box are cumbersome. If building a board from scratch, you could definitely do better. That's a really interesting idea about installing on the bottom....the worry is your water proofing has to be 100% of you're screwed.
For installing on board top, having the wire come through the board would be an improvement -- best in show would be efoil style with a hollow mast and the wire running under the mast plate. Another option is a through hull handle like the new armstrong boards use, with wire through that.
For the battery and electronics, you could have the box sit in a recessed area in deck, ideally flush with board deck, still use the waterproof box. Next level up from there is to build a hatch in the board like efoils. I am not sure if the heat sink inside that hatch would provide enough cooling, or you'd need to expose it, or use water cooling.
I have found my FD is fun in surf ... only had chance to try it twice. Flat water, mixed results. I am skipping the middle man and building a full efoil next, as it's the same everything just bigger. Going bigger! :-) What changed my mind was seeing my buddy ripping around way outside on a big day, picking off bombs on the shoulder. I picture leaving port to travel 5km to chase ferry and freighter wakes, no tow boat or wind assist required. Not quite the same as unassisted wave foil riding...but I am sure it will be lots of fun in its own different way.
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PS in case mods or admins are reading this...I moved my reply above to an earlier Foil Drive thread....but can't figure out how delete it. I guess the Modify button is time limited? As it doesn't show as available.
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New rocker template on top of my older template so the foils are in the same place. The addition of some tail rocker will make the board ride nose up at slow speed and flat at high speeds (hopefully).
Imagine a stall situation where the old rocker submarined the new rocker should bounce back. It’s funny that many brands are straight in the back half and others have tail rocker. Length helps and these are under 5’ so it’s critical
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I was fiddling with Tre Hendrix's Kalama E3 today trying to figure out some of the issues he's having with it (mostly just tuning the foil to be parallel to the board and shimming the tail a little). I put my 6 foot level on it and was surprised to find there's a fair bit of rocker on the bottom.
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I'm building my own foil drives. I'm at V 2.2 right now.
Funny, I was just talking about this at the beach yesterday. We were discussing putting a hole all the way through the deck and mounting the battery pack longitudinally right above the foil. Heat sink would be exposed on the bottom of the board. That would make it nice and low profile and mitigate the heat and swing weight issues.
I gave this serious consideration when I built mine. But you need a 65mm hole and then each time you disassemble the setup you have to remove the motor from the mast. Not so practical. So I have built a carbon recess with a small self draining hole. The wire will still be exteriorised for practicality. The board has enough volume it will not end up underwater
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and from the bottom...
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Looks good Slyde. That’s my Fall project. A foildrive specific board.
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Very nice Slyde. 8) Pretty much exactly what we were envisioning. Good point about the wire routing, hadn't considered that.
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Nice board. Is the hole for water drainage, wire routing or both?
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Nice board. Is the hole for water drainage, wire routing or both?
drainage. The wire cannot be disconnected. It would be perfect if it had a waterproof plug for the battery box. But i think there might be an issue with the amount of current needed for a waterproof plug, but dont quote me on that.
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Nice board. Is the hole for water drainage, wire routing or both?
drainage. The wire cannot be disconnected. It would be perfect if it had a waterproof plug for the battery box. But i think there might be an issue with the amount of current needed for a waterproof plug, but dont quote me on that.
I have half-heartedly looked into removable connections and people in DIY community have discussed options. There are various 3-pin connectors that seem like they'd work, either connecting the motor and esc along the wire somewhere convenient, or installing a waterproof boat-deck mount in the box. However, these options wouldn't work well for you, as you'd have to make the through hull hole quite big to accommodate the plug. Or maybe getting crazy with it: the hole through the board has a has a deck mount on board bottom that the motor wire plugs into, then on board top another deck mount that the box wire connects to. That's two connections to manage but nicely sleek compared to a wire over the tail.
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PonoBill, I hate to trouble you, but since this is the "tail rocker" thread, and since you already have your straight edge out, could you please let us know how much the E3 has and which model you are looking at? I don't know if this is the most useful way, but I like to put the straight edge flush with the tracks down the center-line and then measure how much tail kick (in this case, to the pointy release edge,) and how much at the board's midpoint (at the center-line).
Thanks!
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PonoBill, I hate to trouble you, but since this is the "tail rocker" thread, and since you already have your straight edge out, could you please let us know how much the E3 has and which model you are looking at? I don't know if this is the most useful way, but I like to put the straight edge flush with the tracks down the center-line and then measure how much tail kick (in this case, to the pointy release edge,) and how much at the board's midpoint (at the center-line).
Thanks!
Images of earlier production Kalama E3 boards showed the rocker Bill mentioned,
as seen in the picture below. Can you confirm Bill?
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Ha ha, looks like I'm not the only one convinced by Kalama's thought processes. This is my new SUP in progress too. No tail rocker and kalama tail for a SUP that needs boardspeed to get on foil. The tradeoff is a nosedown attitude in flight. I still think a wingboard needs some tail rocker for better flight characteristics but If the SUP proves to be what people are saying I will try a rockered kalama tail on my next wing board.
I do not understand this.
Why would zero rocker at the foilbox give a nose down attitude in flight?.
Most modern foils are designed to fly level on flat boxes, and if this is not the case you can always shim the mast plate.
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Ha ha, looks like I'm not the only one convinced by Kalama's thought processes. This is my new SUP in progress too. No tail rocker and kalama tail for a SUP that needs boardspeed to get on foil. The tradeoff is a nosedown attitude in flight. I still think a wingboard needs some tail rocker for better flight characteristics but If the SUP proves to be what people are saying I will try a rockered kalama tail on my next wing board.
I do not understand this.
Why would zero rocker at the foilbox give a nose down attitude in flight?.
Most modern foils are designed to fly level on flat boxes, and if this is not the case you can always shim the mast plate.
On a short board (under 6') with minimal nose rocker, adding some tail rocker it will make it feel "nose up" when it rides.
Alternatively, no tail rocker, the flat red line on the kalama board above, will not give this "nose up" feel -- and in some situations that can feel "nose down", like dropping into a steep wave it feels like your board is beyond neutral and actually pointing into the wave -- versus the nose up feeling of a surfboard or a snowboard in powder.
The added blue lines illustrate how the tail rocker makes the board in front angle up, the nose rides is an inch or two higher than it be if no tail rocker.
And yes, you can achieve the same thing with mast shims, either adding more rocker effect or removing it entirely. (unless you have a tuttle mount)
Early sup conversions we found the boards had way too much tail rocker, which caused the foil to be pointing downward when paddling, really bad for paddling power and glide getting into waves.
The tail rocker thing is more pronounced on prone surf foils and shorter wing boards -- eg the sky 5' had a lot of tail rocker. So does the new FG Armstrong boards.
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The board is a prototype of the E3 (I probably should have mentioned that). I have the level handy, but not the board.
I think the radical changes Dave pioneered are driven by the changes in foil design and how people are using them. Moving to higher aspect foil or small foils means board speed becomes important. A high aspect, thin foil section wing that's under 1000sq cm is going to need some speed to get my fat ass off the water. Both flat bottoms, tails that flow, and minimum rocker or kick are all ways to get that speed.
Early on I thought the only thing a board needed to do was float me long enough to get off the water. After that I wanted it to mostly disappear. That works when you're riding a big, thick foil that can lift 200 pounds at 3 mph. I calculated that the 999 Axis wing generates 80 pounds of lift at 3 mph. Of course, my calculations are always open to question, I've been known to lose a zero or forget to carry the one, but I think that's close.
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Nice board. Is the hole for water drainage, wire routing or both?
drainage. The wire cannot be disconnected. It would be perfect if it had a waterproof plug for the battery box. But i think there might be an issue with the amount of current needed for a waterproof plug, but dont quote me on that.
I have half-heartedly looked into removable connections and people in DIY community have discussed options. There are various 3-pin connectors that seem like they'd work, either connecting the motor and esc along the wire somewhere convenient, or installing a waterproof boat-deck mount in the box. However, these options wouldn't work well for you, as you'd have to make the through hull hole quite big to accommodate the plug. Or maybe getting crazy with it: the hole through the board has a has a deck mount on board bottom that the motor wire plugs into, then on board top another deck mount that the box wire connects to. That's two connections to manage but nicely sleek compared to a wire over the tail.
I'm using bullet connectors that are about the same diameter as the wire. After I solder the wire in place I cover the connector and the wire end with copious dielectric grease and shrinkwrap a cover onto it. I'll probably need to refresh the grease on the connectors themselves fairly often, but no big deal. The slim connectors mean I can remove the motor when I choose to--which won't be often, both of the boards I'm modifying will be dedicated to this use--a SIC Manta that I never really warmed to, and a hollow board Mark Raaphorst gave me that he rejected for quality reasons (one the internal braces pulled loose during molding).
There are 3-pin waterproof connectors that can handle 50+ amps, but they are bulky and stupid expensive (I was considering one for $273, but decided that was nuts). The bullet connectors I'm using are rated for 100 amps. The big problem with individual connectors is that it's easy to get the wires swapped, which often means the motor runs backward. Line tags or color-coded shrink wrap resolves this issue.
The board with the Faux Drive also has a 3D printed pass-through gland that clamps the wires to the hull. The gland is also filled with grease. The board with the huge motor and gearbox has the wired going through the mast and passes into the board through a short bit of carbon tube that I glassed into the board. My first thought was to make a compression fitting to seal the wares in place, but I wound up just pumping the tube full of caulking compound.
Both projects have been ignored for the past few weeks because I've been either wingfoiling or working on motorcycle projects and/or fixing my 3D printers. The ones I shipped from Maui had a rough trip, disassembled in flat-rate boxes. I have everything necessary to finish these foil projects and get them on the water. I just need to get off my ass and finish them.
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Hi Ponobill.. thanks for the update.
I've ordered a Foil Drive because I don't have the time to build my own. There's a significant learning curve I would need.
However I'm going to build a new wingboard soon designed to use the foil-drive assist.
What I would like to do is cut the stock cable on the foildrive, and put in a quick-connect like you mentioned. So it's easy to build a through-hull fitting for the cable in my next board.
Can you post some pics of your connectors?
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I use the 8mm though the more common 6.5 mm is more than enough for a foildrive. You can get them from most online hobby shops, castle creations makes some sizes.
(https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fsc01.alicdn.com%2Fkf%2FHTB1Pfm7lrZnBKNjSZFK763GOVXa8%2F200476303%2FHTB1Pfm7lrZnBKNjSZFK763GOVXa8.png&f=1&nofb=1)
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Looks like fanatic is listening... Two stage rocker on the new 2023 Wing Board with much more pronounced tail rocker.
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Apparently no tail rocker with this one:
https://www.youtube.com/watch?v=c_IUfqdwaws
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Apparently no tail rocker with this one:
Seems like a two stage with healthy tail rocker. Similar to their Wing Raider.
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So when they say "flat tail" it really means something other than flat? "What we have here is a failure to communicate."
So anyone know if the Wing Craft V2 has tail rocker as well?
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So when they say "flat tail" it really means something other than flat? "What we have here is a failure to communicate."
So anyone know if the Wing Craft V2 has tail rocker as well?
Craft V2 is the same and so is the Wing Raider. The Wing Raider though has a single concave running from
mid board to the tail so it's not flat in that regard.
As for the two stage rocker, the back part is completely flat with plane once the you rock the board back.
So you are correct, "What we have here is a failure to communicate." ;)
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Gunnar touched a bit on this recently. skip ahead to 34:49 if the timestamp embedding did not work
https://youtu.be/Xx0XEPOuJkw?t=2089
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Gunnar touched a bit on this recently. skip ahead to 34:49 if the timestamp embedding did not work
https://youtu.be/Xx0XEPOuJkw?t=2089
Yeah, he already has that in his current designs but he told me he might go further with that feature.
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To me "flat tail" doesn't mean there is no rocker. It means there is no V or concave or other contours commonly seen on tails. This is carried over from surfboard shaping where rocker is separate from the width-wise contours. Simmons boards have rocker and flat tails. Let's not confuse those.
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I use a SS Shred Sled (5' 9") for really light wind winging with the 8 metre F-One wing. The board has a very long mast track and even with the foil mast at the front of the track the board requires very little front foot pressure (nowhere near even between the feet -- no issues with my 5' 4" 2021 Sky Wing, which does have some tail rocker). I checked the tail rocker and from what I'm seeing the Shred Sled has zero; however, it doesn't ride nose down -- just back foot heavy. Do I shim the stab or shim the mast plate and how best to do either? Thanks for any suggestions.
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consider shimming the mast plate.
Generally if everything flys well and balanced well for your feet but you have trouble during the take off phase - that points to mast plate shimming.
To put it another way - the board wants to ride through the water "slogging" at a certain angle, and transition to planing at a certain angle, and the foil wants to fly at a certain angle. In a perfect setup, those angles are all the same. It would be impossible to do it just with the board rocker because the different brands have different mast plate to front foil wing angles.
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Discussion of tail rocker in this video:
https://www.youtube.com/watch?v=dWq8uE6KLpU&t=403s
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consider shimming the mast plate.
Generally if everything flys well and balanced well for your feet but you have trouble during the take off phase - that points to mast plate shimming.
To put it another way - the board wants to ride through the water "slogging" at a certain angle, and transition to planing at a certain angle, and the foil wants to fly at a certain angle. In a perfect setup, those angles are all the same. It would be impossible to do it just with the board rocker because the different brands have different mast plate-to-front foil wing angles.
Exactly. As far as I'm concerned changing mast position is a way to get from floating in the water to flying on the foil without moving your feet. The same with mast shimming, if you have a substantial tail rocker the foil will act like an elevator on an airplane and tend to push the board down when you're trying to take off. With a rockered board and no shim, you have to push the tail down to have the wing fly in a neutral AOA. Once you're up and flying a neutral wing position is nose up on the board. All this is a lot more obvious when your board is big like mine will probably always be. My smallest wing board is 5'11" X 32. I like float.
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however, it doesn't ride nose down -- just back foot heavy.
In my experience if one is riding back foot heavy the board does indeed ride nose down, the heavy back foot is what is being done to correct or compensate for the nose droop. My solution would be move the mast forward or feet back. Other strategies usually introduce drag (more lift) to try to correct the imbalance.
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I built myself a wing board with more rocker. About like what is shown on the new Sky board, and the boards from KA, ridden by Johnnie Heineken and that crew.
I tested it thoroughly in super light winds to confirm efficiency FIRST, before moving on to high wind testing.
Very impressed.
My feeling in super light wind when schlooging (tail sinking more than the nose) is that foil is actually at a better AOA for lowest drag. With a no rocker board, you need to be schlooging deck more level, to have the foil at the better AOA for lowest drag. So bigger, higher volume boards will be better with less rocker. Flatter schloogers.
In slightly more wind, both get up and go easy, so less important.
In higher wind ripping, the extra rocker places the nose higher, making hauling ass less scary. Might even allow me to ride faster.
Water kissing feels less draggy with more rocker. Like there is less distance longitudinally on the bottom kissing the surface.
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Here's a wind foil video about recommended amounts of rake for the mast. Maybe I'm wrong but it seems to me that by increasing "rake" the added "rake" is having a similar effect on foiling as if you added "rocker" to the board without actually adding rocker (and avoiding any downsides, if there are any).
https://www.youtube.com/watch?v=_0GPCC1TMY8&t=307s
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Here's a wind foil video about recommended amounts of rake for the mast. Maybe I'm wrong but it seems to me that by increasing "rake" the added "rake" is having a similar effect on foiling as if you added "rocker" to the board without actually adding rocker (and avoiding any downsides, if there are any).
https://www.youtube.com/watch?v=_0GPCC1TMY8&t=307s
As you mentioned this is a wind foil video, not wing, and the two sports have substantial differences. Most importantly, the sail is pushing down on the nose, and the boards are generally fairly long. Raking the foil will help a lot with balancing the sail pressure, and riding nose up is beneficial with long boards so that you don't pearl the nose if you touch down.
If the tail of your board sinks more than the nose then some rake makes sense there too. Without it, the foil is angled up, which is as draggy as the foil angled down but without the downward pressure on the nose that an excessive down angle causes.
I winged yesterday using a 3D-printed mast shim to counter the amount of tail rocker on my 5'11" flying Dutchman board. Normally I use two fairly thin Wizard Hat shims but I printed these to be roughly the same thickness as the doubled-up shim. Apparently, I forgot to carry the two or something because they came out too thick. No big deal, I thought, and then struggled mightily with the board. It was trimming nose down a little, so whenever I touched down the board turned into a submarine. removing the shim left the nose a bit high in my normal foot and mast position, but it beat the shit out of doing a face plant when I touched down.
I was using my D-Lab 4.5, which would have been a bit too much wing for the gusts anyway, but with the Alulla strut and leading edge the wing hardly flexes in gusts. A little taco-ing in gusts is a nice thing. I wound up pulling some muscles in my right arm. Still a little tender today. I beat feet to HiTech and bought a F-one Strike V2 in 4.0. I'd been hoping that the D-lab could fill the gap between my 3.5 F-one and the 5.0. Wrong.