Let’s talk rail design as I think board wise that is something parawing has unlocked, and I wanted to try better understand the design.
I never really noticed the issue until I started downwinding with the parawing and riding much smaller foils and going for more carvy sessions. My prone board is a Appletree skipper which admittedly I’m mostly going slow, or trying to go slow, and the rail touches don’t matter that much. But with parawing it seems to have hit my downwind board which has harder rails (pretty standard looking things)
KT has come up with a good rail design seemingly from all the reviews.
I was watching this clip of Kane ripping and realised there isn’t even much good footage of rail grabbing at high speed. Has anyone got any good clips?
The feeling is so distinct though, it’s like riding over a train track at an acute angle and you just get ripped onto a different line until you release the rail.
The newer KT Arc they have slightly more definition, but still look quite soft. Is that part of it? It has a distinct tumblehome line, so it’s not completely rolled.
Any insights? the popular theory from way back when is that hard leads to clean release, and rolled soft round rails “suck” to the water. But seemingly that is a bullshit theory?
Eg compare with the Baraccuda school of though with a flat planing bottom, my board has this sort of rail setup. It makes sense for paddle up, but I wonder about those hard edges?
I think the rail stuff is less important than a lot of people think. I think Dims #1, stiffness 2nd, outline 3rd, rails 4th, Bottom contours are irrelevant, deck complexity(anything but flat) is negative important - can only subtract from a board.
I’ve got 2 downwind boards. One is plywood, literally flat bottom, flat deck, 6” tall flat rail. The cross section is a rectangle. It’s FINE. The only throng wrong is the front of the board doesn’t slip at all and tracks too much getting on foil on the wing(probably would be similar on PW too) it’s fine, does the job, the rails are the lowest gripe on my list with that board
My other is the inflatable with just round bubble rail all Over and it’s great. Love it. It could probably be a hair crisper in the tail for more release but honestly it’s fine. If I could get rid of the bump on the bottom where the tracks are and make it just a hair stiffer I would just ride that.
So in conclusion front needs a softer rail for slip tail needs more bite for Release. Blend em if you want(like surfboards figured out 60 years ago) or not(KT with the step) or just twist that panel For more angle in the front less on the tail(kalama)
For my prone board I have some Side cuts in my shape but I don’t think they do anything. I’ve played with harder and softer release on the tail and I don’t think it makes a lick of difference.
I agree with your ordering, but I think it’s context depending as to how much it can matter (see our last confusion on fixed foot position lol)
Also agree that there is way too much spilt ink on all complexity on the bottom and shit, but when rails bite, it matters, it does matter. (clear 4th of important things as we agree)
My point is I think what is overdone is the hard rails on downwind style boards for release, which arguably isn’t needed for parawing (as much), and it comes at the direct expense of getting train tracked (or railed? idk)
Same with surfboards: dims, outline, rail, the rest is all bullshit
I think the biggest factors in board design are construction process limitations(you gotta Glass it) and aesthetics(it has to “look good” to a surfer’s eye for it to sell). Also it’s a thing to change to sell the new hotness over the old busted(marketing). I think we can break from the aesthetics thing but only If there’s a Clear performance advantage (thanks kalama) but I don’t think we can break from it for cost savings alone(this ugly Board is cheaper To Make and doesn’t perform Any worse - not Gonna sell)
I’m sure it matters for someone in competition in those DW races where that 2% gets you up on a smaller foil which nets you 5 secs/mile but for me it’s just useless complexity adding $$$ to the process.
I think @JudoChop can offer some insight here given his involvement with the Project Drag board with Ken Adgate being at the helm. Ken honed this shape and rail lines with the attitude that if your rail isn’t touching the water, you aren’t turning hard enough. Years of high speed wing tacks on Mikes lab foils aided in this approach, surely, and now with DW surf a thing thanks to the parawing, that approach is really paying off. I’ve yet to see one in the flesh, but I’m pretty sure there are a lot of subtle rail shapes/angles that are allowing the turn to be completely unaffected by the rail touch down. Depending on where the rail touches, it is likely at a different part of the arc.
Yes I think so. I’ve historically been sub-relevance for the rails where some grip wasn’t that bad on the straight edge boards. Now going faster it comes into play
I love this topic. Yeah… I do think rail touchdown performance is critical; and unlocks a whole bunch of ways to ride a foil, let’s you push a lot harder, and can save you a lot of times when you (when I) get clumsy.
you are right… the old saying of water sticking to curves and releasing from angles is certainly still true, and applicable.
TooMuchEpoxy - I’m not sure I’d really rank importance in general, since all of those make a difference. but you’re missing a big one : balance. If we are ranking, Id put that at least second place… maybe even most important. rail performance pretty high on my list too.
Personally it was something that actively really frustrated me in how many boards performed in rail touches, so I tried to fix the problem.
But everyone rides differently. Probably not a big deal if you like to always stay high on foil, or mostly do yaw turns vs roll turns.
And I guess… fine is fine, if you are fine with “fine”
The bevels are more like a spiral vee with a slight nested double concave. So not really parallel to either. You get a different rocker at centreline vs rail
From Jimmy Lewis vid i thought spiral vee is when the bevel changes angle through the board lenght.Those bevels look pretty constant angle but the paint scheme is probably hiding a more complex shape.I see they converge at the tail.
@JudoChop that’s very interesting. Can you by any chance share some good footage of testing, touch downs etc? Does anyone have interesting footage of this? I feel like I’ve seen good footage of breaches, ventilations, tail breaches, etc etc but note much on this
Ok here is one, it illustrates the point where he got wrong footed when the rail grabbed. (though that was surely makable sorry not sorry influencing cuts both ways here people)
Anyway this video is the exact conditions I was struggling in where similar scenario super chopped up ocean and going fast on open ocean swell I’d grab a rail and get train tracked and that was it.
I put bevels on mine and soften the nose rails to mid of board.
Boxy edges are great for release and they maximize static stability for the width.
But i have noticed that sharp rails and/or lots of vertical sidewall behave weirdly when the sea state gets livelier.The edges and sidewall thend to dig in and release suddenly even when floating.Plus the effect on rail touch downs.
looks a bit like the bottom of the Smik board, very boxy edges but where Smik kept shaping the tail with a hatchet, Starboard goes on to more rounded transitions to deck and tail. Trying to “smooth out” some curves that are pretty much unsmoothable, lol. And making it bright color so your eyes are all over it. And probably slapping a hefty price tag.
I got used to the look of the Smik. It’s got a fat ass, but as an overweight guy, who am I to expect slim flowy lines? Always a tradeoff somewhere, but that seems to work. Definitely great stability and release, but can’t comment on the rail touchdowns, I’m probably not banking hard enough.
It is all about finding your balance of this and that.Big bevels mean you need a thicker board for the same width and lenght to maintain volume.
On my next one i might play with narrower (i was too cautious at 21.5in) and tail rocker.That helps with turns and glide to boot.
I like the back foot pressure of a straight tail but it does block the pitch on take off quite a bit.This was very good as i started riding smaller ,higher aspect foils.They stall easy.But current foils are very well balanced and i am getting better at feeling the pre stall mushiness.
Midlenghts are a lot glidier and that board pumping motion as you accelerate looks more efficient than the solid lift a straight tail gives.
Specially for low power takeoffs like a parawing in light wind or a paddle up.
Would love to try one of those Adgate boards, hype aside they are designed by a guy who rides like a devil instead of CFD, Engineers and marketing department.Must be good
The subtleties of surfboard bottom contours “bullshit”? Not by a longshot. Take two identical shape, size, volume, surfboards and you’ll find subtle bottom contour differences not even visible to the naked eye make or break how a particular board rides - even for the average Joe. Therefore, the consideration of rail shape during high speed water touchdowns is absolutely valid. Obviously solving for a different set of issues when your board is mostly flying through the air, but the cross-section of the rail, whether C-shaped, or with a sharp break like a chine or somewhere inbetween, there’s a particular design that will maximize bouncing off the water with the least grab.
With surfboards, a more rounded rail profile has more grip and a sharp edge provides more release.
The bottom design matters. It’s definitely not only the rail shape that makes or breaks the touchdowns. We have come a long way from the times when people who claimed the design of the foil board does not matter at all (just needs to release from the water) because it’s in the air all the time, to a point where they themselves are starting to appreciate the more nuanced designs.
Here at 02:14 there are a couple of slightly higher speed touchdowns. It’s nice when the bottom of the board interacts with the water in such a way that you nearly don’t even notice it.
sorry not sorry influencing cuts both ways here people)
