My goal would be a pump in the wing. enough battery to pump a couple times. Imagine you just toss your wing on the beach and press a button. Idk, one can dream.
THIS. I think Armstrong was playing with the idea of crazy small mid aspects but someone said they were having issues getting the foil section they want and having something that wouldn’t be too weak to actually use. New materials will boost this sport. I think some spiders are weaving web materials that can be bulletproof and ridiculously light. Imagine when we copy it synthetically.
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I think this is like an aircraft designer in 1925, 20+ years after the Wright brothers 1st flight, saying “We have reached a peak of aircraft performance . . .” AND THEN!!!
Hydrofoils have not been optimized like airfoils over the past 122 years. More specifically hydrofoils designed to operate at 10 - 20 mph with a ‘wing’ loading of 100 - 150 lbs per Square foot (1 ft^2 = 929 cm^2). Its all new territory with no prior monetary, or militarized incentive.
It’s not just materials, its design & manufacturing improvements - Example When Axis realized in July 2025 (at the races) their highest performance mast and foils were covered with Bi-Axial carbon acting as a cosmetic vs. performance outer layer. Then they sanded the aesthetic layer off. Now focused on using Uni-Directional carbon as outer layers.
Its further optimizing foil shapes, making hybrid steel-carbon structures (more on this later) . . . .
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See the latest conversation between Erik Antonson and Kai Thompson, 3rd overall in 2025 Hawaiian race series.
Erik @ 1:08: “How much better do you think foils can get?
Kai: A lot.
Erik: A lot!!!
Kai: I don’t think we’re even halfway there.
Erik: What do you think changes?
Kai: A lot of improving. Have you seen the moth stuff? Yeah.
The technology is all there. We just haven’t introduced it into our world. Like, their mast, they are metal, but they’re tiny.
The (mast) cord’s 50 mils, like two inches. And then they’re stupidly thin, like below 8 mil, I think, which is crazy. So we’re, we’re behind.
The gear is there and the technology is there. We just haven’t brought it in correctly or brought it in yet. So we can definitely go a lot faster.
I’m excited to see how we go next year, because the gear is, like everything you’re on now is obsolete by next year, at least for the racing. Like you’re, you’re not always pushing, like AXIS is pushing. I love it so much that they’re, they want to have the best always.
They’re (AXIS) like, we’re not here for a fair advantage. We want to give you like the best opportunity possible.
From The Progression Project: 157 - Kai Thompson, Oct 8, 2025
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Carbon vs Steel: Moth Mast Evolution
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I know at least one company is pursuing this for their wing foil racing gear.
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What i hope is to see more systems which can be fast asambled like the Slingshot Onelock. Do you think the brands will move soon to that designs or isn’t important for them?
Lift efoil looks even faster. Mast clicks into the board. No tools needed.
I don’t think so.
Foilers want a lot of things: more pump, glide, carve, rigidity, less weight, etc.
I’ve never heard someone complaining about hainv to spend 20 seconds to screw things up.
Slingshot format also comes with the drawback of having a very specific connection removing the possibility to use adapters to other brands.
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There is no way we have reached the limit of what Foils can do. I just upgraded to the latest Armstrong MAs MK2. The maneuverability, control, and overall fun is an incredible change from their previous MAs. We just had 6 to 8 foot waves in Hatteras and with that foil I no longer had brown stains in my shorts. The innovation were seeing in this sport is truly epic.
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Love the idea of a wire frame structure that you could twist and fold.
Heaps better. I think the masts have been holding back the foils for a while now. Next year we’ll see a ton of new masts hitting the market from the big names. Then the new foils can be developed on the new masts. It just keeps leapfrogging itself.
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@McD could maybe comment on how viable this is for us, he is working on both moth foils and race wing foils
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100% viable - though the Moth has some unique characteristics that lead us to different solutions than might work best for either wing or downwind foils.
Can’t say much more for now, but there are some exciting developments underway… Stay tuned!
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thanks for pointing this out Beasho, the moth foils link is interesting. I thought the answer given for “why stainless steel” missed half of the reason. Yes it is stiff and strong in all directions while carbon is unidirectional. But importantly, the reason people love carbon fiber composites is the specific stiffness and specific strength - meaning for its weight, it is the most stiff and strong. But if we are designing for the highest stiffness with the smallest cross-sectional area regardless of weight, Steel can be a better option. But it will certainly be significantly heavier.
One of the highest modulus carbon fiber is Toray M60J. It is ridiculously expensive and nearly impossible to get and has a tensile modulus of 588GPa. When mixed 60/40 with epoxy, the resultant stiffness properties are 360GPa in tension. But most importantly, if we need a layup for both bending stiffness and torsional stiffness, we’ll need three layers of unidirectional carbon 0deg, +45deg, and -45deg. We don’t need much 45deg ply compared to 0deg, but it still reduces the overall effective bending stiffness quite a bit. And we will need to mix in some layers of lower stiffness carbon because the ultra high modulus carbon fibers are so brittle - they need some less brittle layers for durability. Stainless Steel has modulus of 200GPa, and by the time we get all the carbon layers we need in a mast, the Stainless can be stiffer (and/or thinner cross section). It will absolutely be significantly heavier though.
Carbon/Epoxy is about 1.7g/cm3 while Stainless Steel is 7.8-8g/cm3 - more than 4x heavier.
Anyway, I bet we’ll see stainless steel masts for very niche racing applications because it can be slightly lower drag, but I doubt we’ll want that mass for most applications.
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On using computers for foil design, XFOIL is a free open-source software that analyzes two dimensional airfoil section. Think of slicing a foil like you slice salami and XFOIL will tell you what the airfoil “slice” or section is doing where ever you analyze it, like near the wingtip or near the fusealge or many places in between. Here is a screenshot of an XFOIL analysis of an airfoil section, the pressure distribution is shown at the upper section for both the upper surface and lower surface from the leading edge to the trailing edge and the airfoil cross section is shown in the lower section. (I did not do this, is just from the web).
CFD which stands for computational fluid dynamics is three dimensional software which used to be very expensive and complicated to have and run and now is much easier and cheaper (even free). OpenFOAM is a free, open-source software toolbox primarily used for computational fluid dynamics (CFD), typically CFD would look at snapshot of the front wing, mast fuselage and tail at the same time and give results on efficiency (glide) and stability (turnability and feel). Doing multiple runs of OpenFOAM one could compile a “movie” with many connected frames to simulate straight line pumping or turning on a wave and get more detailed and nuanced feedback though even interpreting the results of simulations like these are very involved. Below is a screenshot of an OpenFOAM analysis I did for a flying car project where it shows the surface velocity and streamline velocity of the three dimensional flow, this 3D type of analysis along with incremental experimental/prototype testing will yield lots of improvements in the future as alot of the fuselage geometry and how the wings and tails and masts interact with the fuselages are sub optimized (in my opinion).
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I would love to see an example of a foil “movie” (as you say) through some pumping, gliding and turning motions. even of two different foils at opposite extremes for comparison. that would be great for better understanding.
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I wanted to tack on to this thread to ask some questions about how much better foils have become (as someone relatively new to the foil journey).
In the latest podcast with Jeremy Jones, Eric says “V1 to V2 was like 100% better. V2 to V3 was probably 25, 30% better. And now we’re probably down into that 5%, 3%, 2% range.”
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I’m curious what people thoughts are about which foils define these different iterations/generations v1,v2, v3?
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It seems like most of the improvements in this time have been with the front wing design. Anyone care to quantify the improvement to masts/tails in this same period?
For context, I’m using an original unifoil carbon mast and race tail. My mantra has been, don’t sweat the gear just put the hours in, but I’m starting to wonder if these components are due an upgrade.
V1 is a gofoil kai or Naish thrust and v2 is somewhere between a Unifoil hyper and a kujira 1095 I reckon.
tails have improved lot but Unifoil race tail was always a lot better than some of the other horrific v1 tails. In fact if we’re doing v1, v2, v3 etc for tails it’s more a v2.
masts is more tricky. The early Unifoil mast is 12.8mm thick and tapered to a chord of 100mm BUT they’re probably 25% bendier than today’s slim masts. However, if you’re 25% lighter than the other guy (on a newer mast) then you’ll be feeling similar. People who’ve only used thick masts get really excited when they use a 12-13mm with narrow chord. You’ll be getting that efficiency already. In a straight line great… when u turn hard less so
Demo some different gear. Swap in the water with someone else out there. If you don’t feel a difference that’s great. If you do feel a difference, but don’t think it warrants spending more money, that’s even better. Foil brands are basically all good now. They all leapfrog each other with each new release. But one brand will fit the way you ride better than another brand will.
Rough estimates that make sense from my experience.
V1 2018.
V2 2019-2020
V2.5 HA foils take over 2020-23
V3 Mast warfare 2023-current.
If your setup is from 2023 or newer, you probably don’t need to spend money. But new gear is fun, so, spend money.
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