The other thing to consider is that the rider will generally move forward on the board when the foil is moved forward.
To fly straight the force of gravity acting on the whole system needs to be equal to the lift generated by the foil, and the effective summed location of the COGs of the rider + board + foil must be directly above the effective centre of lift. By effective I mean taking into account the moment generated by the stab so your picture can be representative assuming different stabilizer shimming.
Continuing the idea that you shouldn’t foil drive onto waves but rather chip into waves, because the trim will be better
This video is a perfect example of why motoring on foil onto waves is a complete disaster. Also a good example of why efoiling looks so terrible on wave when done this way.
Note how he has to pump while on foil even though the wave has plenty of energy. This is because so far forward. And the turns are terrible and keep bogging.
He is standing at least 30cm forward of where he should be standing, and it shows. This is exactly the issue
Riding a foil without a stab is possibly a good way to feel out the trim of a foil, as the idea behind this thread is that you should be standing in such a way that the stab is not used at all, in which case you’d not miss it much if you removed it
So in the plane analogy the back foot is your elevator and all pitch control happens via back foot pressure. If you were to stand on the front foot and balance you would glide fully trimmed. So instead of pushing down with your front foot during a pump think about lifting the back foot. This doesn’t seem to be what Kane does as his back heel never even comes up (in that video anyway).
I disagree with that one personally. I’m working pretty hard to get weight equal on both feet when gliding and when pumping. For downwinding it is almost a requirement or you’ll burn out one leg fast
Yeah I don’t think it would work either unless you had a back foot strap to pull up like a plane’s elevator can do. So the question still remains where it might be best to have your your feet. Obviously your front foot needs to be forward of the main wing and your back foot behind it.
Watch how the feet shift in this clip. The paddle up is further forward to get the board moving, but as soon as the foil is properly lifting the feet are moving back to get the optimal trim. Notice at the end how the slow down to a stall leads to the angle of attack going very high right before the stall, that is what a well trimmed foil does when it stalls, it “rears up”. If you are stalling and touch nose down first or flat when you stall, you’re too far forward.
if one can’t imagine one’s own foil turning like that it’s because 1- one is standing too far forward, 2-leading to bogging turns because one loses lift as soon as one puts it on the rail, 3- leading to one’s itch to buy a “better foil” which one will also stand too far forward on
I jumped off my foil while pumping at efficient speed, and the board kept gliding perfectly, for about 10m before it slowed down, nosed up and stalled.
Do you think roughly that that is the equivalent to your balance trim advice? Where the board is neither nose heavy or tail heavy, and maximises glide?
I’ve never seen a better example of how important it is to stand with your front foot tucked under your knee not in front of it. Sorry to linked poster I think this was just fatigue later in the race, but it’s a great example of how you can see the back knee is just getting torched and the front knee is overextending like crazy.
I could use some more input on this really helpful topic…been foiling regularly in the gorge this summer and making a lot of progress, except on this front.
My stance continues to be forward, if judging both by position relative to center of lift of the foil, and the firmness/feel when pushing to pump…but it feels very balanced to me, neither leg gets burned out before the other, and my turns are controlled.
When I do move all the way back to where the advice here says I should be (and where my better self believes I should be) a number of things happen…firm platform for pumping, I ride higher on the mast and get better glide on swell…AND I breach a lot more riding swell and jibing.
My better self would advise…“OK, just make the adjustment by moving back where you should be and take the time to learn to adjust your weight so you don’t breach”, but my actual self keeps inching forward to avoid breaching…
A stab shim that flattens out the stab a bit should allow you to move back relative to the mast since you won’t need to be so far out in front of it to keep the nose down. As a light weight rider this is one of the things that really unlocked foiling in control for me.
Oh nice! Same weight here, and have also recently switched to Hydrocraft. One of my concerns when thinking about the purchase was lack of shim ability in the system. I have had Uni and Armstrong and in both I found great benefits from shimming the stab flatter. In my discussions with the HC guys they assured me that I probably wouldn’t need to do the same with their kit. I’ve been on the 775/140 since the first batch came in about a month ago and have been really pleased and haven’t felt the same need to shim. That said, Matt did tell me that they were working on a special tail that would have shim ability for tuning testing so you might inquire about it if you are curious.
I assume you are also on the 140 Pivot tail. You might try to demo the 120 and see if that takes some of the nose lift out and helps settle things down during the speed surges for you.
Have the Helix 775 and 900…just the 160 tail right now but planning to add the 140 (and really loving the foils…my issues predate are clearly independent of the switch to Hydrocraft…and I’ll add that the Helix does seem to have an uncanny ability to ride high and sit steady just below the surface compared to the Uni Progressions…but I still find ways to breach, esp. when conditions pick up)
Oh yeah I bet the smaller stab will help a lot. My 775/140 kit feels really well balanced for me at the same weight as you.
The Pivots are also shorter fuse length than the Drift so that should also help reduce the lifting leverage that is pushing your nose on the over speed situations.
Bring your board down to the shop, so we can take a look at where you have the foil mounted and where you’re usually standing. I’ve got some ideas that might help!
When I’m tow foiling or prone foiling with a small foil, my stance looks similar to the foiler in the black leggings, maybe a bit wider. I have a hard time shuffling my front foot back to narrow my stance because it feels like I will breach. I’m slowly coming to the realization that I have to move my back foot forward to be just in front of the mast BEFORE I move my front foot back. This way, it’s easier to get weight over my front foot to prevent a breach.
When I dock start with a big foil, my stance looks more like the foiler in the shorts. When I launch from the dock, my back foot normally lands right in front of the mast. Probably due to the slower speeds from flat water pumping, it feels much easer to adjust my front foot to a shoulder width stance if I land slightly wide.
