Get a smaller stabiliser (tail)

Jedibrad said..
From experience?

www.seabreeze.com.au/forums/Stand-Up-Paddle/Foiling/Armstrong-1550-with-232-tail?page=3

I have blown foils out plenty on swells but cant say i have ever been able to rationalise it to being the rear that is blowing out. Usually a breach or a dive happens so fast that you just hit the water, but if it helps to figure out your problem I would say that there is a fair bit of confusion about how and what a stabilizer does. A foil that feels really comfortable at low and moderate speeds may very well not be balanced as it reaches higher speeds and this is typical of the bigger slower low aspect foils like the 820. A really interesting thing to try is to take your setup out on a windy day in flat water and crank it up as fast as you can. I mean push it to the bleeding edge. This simulates the speed you develop dropping in to a large swell face. You will likely find that the foil starts to lift alot and then begins to dive the faster you go and you need more back foot pressure to keep it level. This is because the average low aspect surf foil has thick profiles and the drag gets to the point that the foil gets tilted down by the drag and dives. The rear wing has a reversed profile and is designed to create downforce to lift the front wing up. It does not directly generate lift, but indirectly it does by allowing the front wing to generate lift. That is why a larger tail gives you a more lifty foil. The tail does not work by creating drag although the bigger it is the draggier it will be, and as you go faster the tail goes down, not up. So contrary to what alot of riders think, as you approach the limits of your wing, the more downforce you need the tail to create to make you balanced. Look at a racefoil , it usually has a very large tail. If you look at your setup i would say it is likely you are pushing the 820 beyond its sweet spot for speed and rather than the tail blowing out the front wing is diving. Cutting down your 500 tail has likely reduced its downforce so you have lost some balance at speed. The guys who are suggesting a smaller tail will be correct when you are at moderate speeds where the lift of the front wing will be lessened by less tail downforce but as you approach that higher speed draggy zone it will start to dive again. So you have a bunch of options to make it work better but all have tradeoffs. You can keep the 820 and go back to a larger tail, or you can ditch the 820 and get a less draggy front wing. The suggestion to go high aspect is good because it sounds like you have got to the point where you are pushing your gear beyond its design curve. HA wings (or thinner high speed wings) have less drag compared to lift so dive less at speed and are less sensitive to tail size. This then allows you more freedom to experiment with smaller tails with the added benefit of a more turny foil. But the tradeoff is that you will lose at the low end a little. Really good riders will have a bunch of wings and tails and match their setup to the likely speed of the swells on any given day or just have the skills to keep a foil in the water beyond its sweet spot. There is no one size fits all.
Of course its possible that all this bs is irrelevant and all that happened is that you ran into some turbulent water and the foil ventilated. Lots of videos of guys riding waves and suddenly smacking down for no apparent reason. Usually thats just a patch of aerated water.

Thanks for the replies, waiting on the 101 but surely as we get the next best wing we will just push that to it's limits. So a good idea on why this happens is a good thing. I have a bunch of smaller rears, I just don't what to waste good days, the pain of being on the wrong gear is terrible.
I do push the 82 to speeds I never thought it could do when I'm winging onto the swell waiting for it to feel the bottom and slow a little. I then drop the wing by my side and from now on it could blow up. So the difference between driving the board forward with your feet (going the fastest, pushing it but in control) to dropping the wing to your side and the foil provides all the thrust forward, a lot changes.
In the same vain I've seen a few clips lately where they are riding suspiciously low ....

The stabilizer doesnt have anything to do with the pitch angle of the front wing. It is only there to provide positive pitching moment (call it ppm), Yes it affects the total lift of the foil but this is due to altering the pitching moment not AoA or drag (more ppm = more weight needed to keep the nose down)